JP2005332673A - Manufacturing method of display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a display panel of high quality at low cost without extending the manufacturing time. <P>SOLUTION: This is the manufacturing method of the display panel in which a sealing layer 7 formed so as to surround a discharge space S between an opposed pair of front substrate 1 and a rear substrate 4 is heated and by softening this sealing layer 7 at a prescribed temperature and sealing the substrates, the discharge space S is sealed. Before a sealing process for sealing the discharge space S by the sealing layer 7 is carried out after the temperature for heating the sealing layer 7 has reached a softening starting temperature of the sealing layer 7, a first exhausting process for exhausting the discharge space S and an introduction process of introducing a substitution gas to the discharge space S after this first exhausting process are carried out. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a display panel.

  FIG. 1 is a longitudinal sectional view showing a panel structure of an AC drive type reflection type plasma display panel (PDP) which is an example of a display panel.

  On the inner surface side of the front substrate 1 of this PDP, row electrodes X and Y each composed of transparent electrodes Xa and Ya made of ITO and bus electrodes Xb and Yb made of thick film electrodes such as silver are paired. A row electrode pair (X, Y), a dielectric layer 2 covering the row electrode pair (X, Y), and a protective layer 3 made of MgO or the like covering the dielectric layer 2 are formed.

  Further, on the inner surface side of the rear substrate 4 facing the front substrate 1, it extends in a direction intersecting with the row electrode pair (X, Y) and is in the discharge space S at a position intersecting with the row electrode pair (X, Y). A column electrode D constituting the discharge cell C, a column electrode protective layer 5 covering the column electrode D, and phosphors color-coded in red, green and blue for each discharge cell C on the column electrode protective layer 5 The layer 6 and the partition (not shown) which divides the discharge space S for each discharge cell C are formed.

  Then, in the discharge space S formed between the front substrate 1 and the back substrate 4 and having the peripheral edge sealed by the sealing layer 7, a mixed gas with neon Ne containing 5 to 10% xenon Xe is discharged. It is sealed as a gas.

  The phosphor layer 6 emits light when excited by vacuum ultraviolet rays (wavelength 147 nm) emitted from the Xe gas by discharge.

  FIG. 2 is a process explanatory diagram showing a conventional manufacturing method of the PDP having the above-described configuration, and FIG. 3 is a diagram showing a relationship between a temperature change in the baking furnace and a process elapsed time in the conventional manufacturing method. is there.

  Next, a conventional manufacturing method will be described with reference to FIGS.

  First, in the front substrate manufacturing step s1 of FIG. 2, the row electrodes X and Y are formed on the front substrate 1 by a photolithography method or the like, and then the dielectric layer 2 is formed by a screen printing method or the like. The protective layer 3 is formed by forming a film.

  On the other hand, in the back substrate manufacturing step s2, the column electrode D is formed on the back substrate 4 by a photolithography method or the like, and then the column electrode protective layer 5 by the screen printing method or the like and the partition by the sandblast method or the like are sequentially performed. After being broken, the phosphor layer 6 is formed by filling and baking the phosphor paste between the partition walls.

  Next, a glass frit for sealing is applied to the peripheral portion of the surface of the back substrate 4 manufactured as described above facing the front substrate 1 and pre-baked at a temperature of about 400 ° C. Thus, the sealing layer 7 is formed (step s3).

  Then, the back substrate 4 and the front substrate 1 on which the sealing layer is formed are opposed and overlapped so that the row electrodes X and Y of the front substrate 1 are orthogonal to the column electrodes D of the back substrate 4. (Step s4) In this state, the front substrate 1 and the back substrate 4 are put into a baking furnace (step s5).

  Thereafter, as shown in FIG. 3, when the temperature in the baking furnace is increased and the temperature reaches the sealing temperature t1 (about 450 ° C.), the sealing step in which the sealing temperature t1 is set in advance. During the sealing step period p1, the sealing layer 7 formed on the back substrate 4 is welded to the front substrate 1 by heating, so that the space between the back substrate 4 and the front substrate 1 is maintained. The periphery of the discharge space S formed is sealed (step s6).

  After the elapse of the sealing step period p1, when the temperature of the baking furnace is lowered to a predetermined temperature t2 (about 400 ° C.) lower than the sealing temperature t1, the glass frit of the sealing layer 7 is solidified in advance. This temperature t2 is maintained during the set exhaust / baking process period p2.

  Then, in the exhaust / baking process period p2, the front substrate 1 and the rear substrate 4 are heated (baked) at the temperature t2, and the exhaust from the discharge space S is performed to evacuate the discharge space S ( Step s7).

  When the evacuation / baking process period p2 elapses, the discharge gas is introduced into the discharge space S at a predetermined pressure (400 to 600 Toor) in a state where the temperature in the baking furnace is lowered to near normal temperature ( Step s8) After the introduction of the discharge gas, the exhaust pipe used for introduction of the exhaust gas and the discharge gas is sealed with a burner or the like (step s9).

  Then, a drive pulse is applied between the pair of row electrodes X and Y of the front substrate 1 to generate a discharge for a predetermined time, thereby activating the protective layer 3 formed on the front substrate 1 and stabilizing the discharge. (Aging) is performed (step s10) (see, for example, Patent Document 1).

In the conventional display panel manufacturing method as described above, in the sealing step s6 for sealing the discharge space S by the sealing layer 7, the space between the front substrate 1 and the rear substrate 4 during the sealing step period p1. Is filled with an impurity gas released from the substrate by the atmosphere and heating, and the inner surface side of each substrate is exposed to an impurity gas such as H ₂ O and CO ₂ under a high temperature condition.

  This is a very unfavorable state for the display panel in the manufacturing process, and the front substrate 1 has a problem that the degassing process for MgO forming the protective layer 3 is hindered. This causes a problem that the fluorescent material forming the phosphor layer 6 deteriorates.

  In order to avoid the occurrence of such a problem, the exhaust time from the discharge space S in the exhaust / baking process period p2 is set to be sufficiently long, and sufficient degassing from the protective layer (MgO) 3 and the deteriorated phosphor It is conceivable to adopt a technique such as recovery of the layer 6 or a technique such as vacuum sealing that seals the discharge space S in a vacuum environment.

  However, if the evacuation / baking process period p2 is set to be long in order to perform sufficient evacuation, the manufacturing time becomes very long. Also, in order to perform vacuum sealing, since the apparatus for that is large, This increases the manufacturing cost.

JP 2000-30618 A

  An object of the present invention is to solve the problems in the manufacturing process of the display panel as described above.

  In order to achieve the above object, a display panel manufacturing method according to the present invention (the invention described in claim 1) is positioned so as to surround an internal space between a pair of substrates opposed to each other with a predetermined interval. In the method of manufacturing a display panel, the sealing material is heated by heating the sealing material, and the sealing material is softened at a predetermined temperature and welded to the substrate to seal the internal space between the pair of substrates. After the heating temperature reaches the softening start temperature of the sealing material, before the sealing step of sealing the internal space between the pair of substrates with the sealing material is performed, the internal space between the pair of substrates is evacuated. The present invention is characterized in that a primary exhaust process and a process of introducing a replacement gas into the internal space after the primary exhaust process are performed.

  The present invention heats the sealing layer formed on the back substrate so as to surround the discharge space between the front substrate and the back substrate facing each other of the PDP, and softens the sealing material forming the sealing layer In the method of manufacturing a PDP in which the discharge space is sealed by welding to the front substrate, the temperature for heating the sealing layer starts softening at or near the softening start temperature of the sealing material. After reaching a temperature slightly higher than the temperature, before performing a sealing process for sealing the discharge space with a sealing layer, a primary exhaust process for exhausting the discharge space from the discharge space at a predetermined pressure, and this primary exhaust A method of manufacturing a PDP in which a replacement gas introduction step of introducing a replacement gas into the discharge space is performed as the best embodiment.

  According to the PDP manufacturing method of this embodiment, a sealing layer is formed on the rear substrate facing the front substrate at a predetermined interval so as to surround the discharge space. When the temperature in the baking furnace in which the front substrate and the back substrate facing each other are increased, the sealing layer is heated, and the sealing material forming this sealing layer is welded to the front substrate. Thus, the discharge space is sealed.

  At this time, an increase in the heating temperature in the baking furnace is started, and immediately after the heating temperature reaches the softening start temperature of the sealing material or a temperature slightly higher than the softening start temperature, The primary exhaust from the discharge space is performed through the connected exhaust pipe, and then the replacement gas is introduced into the discharge space where the primary exhaust is performed.

As the replacement gas, a gas not containing H ₂ O and CO ₂ is used. For example, an inert gas, a mixed gas of inert gas and hydrogen gas or oxygen gas, oxygen gas, nitrogen gas, fluorine gas, chlorine Various gases such as a gas, a mixed gas of nitrogen gas and hydrogen gas or oxygen gas, a mixed gas of fluorine gas and hydrogen gas or oxygen gas, and a mixed gas of chlorine gas and hydrogen gas or oxygen gas are used.

  According to the PDP manufacturing method of this embodiment, it is possible to obtain the same effect as that of manufacturing a PDP using a vacuum sealing furnace, and to solve the problems in the conventional manufacturing method.

That is, in the PDP manufacturing process, heating is performed to seal the discharge space between the front substrate and the rear substrate, and the discharge is performed after the heating temperature of the sealing layer reaches the softening start temperature of the sealing material. Since the primary exhaust and the replacement gas are introduced from the space, the discharge space is released from the substrate side by the atmosphere filled with the discharge space and heating before the sealing process for sealing the discharge space with the sealing layer is performed. By discharging the impure gas coming, for example, degassing from the MgO layer formed on the substrate is promoted, and further, the inner surface side of each substrate becomes impure gas such as H ₂ O, CO ₂ under high temperature conditions. Since the exposure is prevented, for example, the phosphor layer formed on the substrate is prevented from deteriorating, and thereby the panel performance (discharge characteristics) of the PDP can be greatly improved. .

  And according to said manufacturing method, after sealing discharge space, the said effect is set without setting the process time which exhausts from this discharge space to a long time, or using a large-scale vacuum sealing apparatus. In addition, since the conventional manufacturing apparatus can be implemented with simple changes and modifications, the manufacturing cost does not increase significantly.

  FIG. 4 is a process explanatory view showing a first example in the embodiment of the display panel manufacturing method according to the present invention, and FIG. 5 shows the temperature change in the baking furnace and the process elapsed time in the manufacturing method of the example. FIG. 6 is a schematic configuration diagram of a baking furnace used in the manufacturing method of the same example.

  The manufacturing process of FIG. 4 will be described with reference to FIG.

  First, a row electrode pair (X, Y) is formed on the front substrate 1 by a photolithography method or the like, and a dielectric layer 2 is formed by a screen printing method or the like so as to cover the row electrode pair (X, Y). Further, a protective layer (MgO layer) 3 covering the back surface of the dielectric layer 2 is formed (front substrate manufacturing step S1).

  On the other hand, a column electrode D is formed on the back substrate 4 by a photolithography method or the like, a column electrode protective layer 5 covering the column electrode D is formed by a screen printing method or the like, and a sand blast method or the like is formed on the column electrode protective layer 5. A partition wall for partitioning the discharge space S is formed, and a phosphor layer 6 is formed by filling and baking the phosphor paste between the partition walls (back substrate manufacturing step S2).

  When the front substrate manufacturing step S1 and the back substrate manufacturing step S2 are completed as described above, a sealing glass frit is then applied to the peripheral portion of the surface of the back substrate 4 facing the front substrate 1. And the sealing layer 7 is formed by baking at the temperature of about 400 degreeC (process S3).

  After that, the front substrate 1 and the rear substrate 4 are overlapped with each other so that the row electrode pair (X, Y) and the column electrode D formed on each of the front substrate 1 and the rear substrate 4 are orthogonal to each other (step S4). In this state, as shown in FIG. 6, it is put into the baking furnace H, and the exhaust pipe 10 is connected to the exhaust hole formed in the back substrate 4 and sealed (step S5).

  An exhaust pump 11, a replacement gas introduction system 12, and a discharge gas introduction system 13 are connected to the exhaust pipe 10.

  In this state, heating in the baking furnace H is started, and as shown in FIG. 5, the temperature in the baking furnace H is a temperature t2 at which the glass frit of the sealing layer 7 formed on the back substrate 4 starts to melt. When a temperature t11 (about 425 ° C) slightly exceeding (about 420 ° C) is reached, the temperature in the baking furnace H is maintained at this temperature t11 during the sealing process period P11 set in advance from that point. .

  Immediately after the start of the sealing process period P11, the exhaust pump 11 is driven to start primary exhaust from the discharge space S formed between the front substrate 1 and the back substrate 4 (step S6). ).

  At this time, the glass frit of the sealing layer 7 is in a state where the surface thereof has started to melt and seals the discharge space S, but its fluidity is low, so that the primary exhaust of step S6 is performed. Even if this occurs, the sealing layer 7 is not drawn into the discharge space S due to the negative pressure in the discharge space S.

  After the primary exhaust, the replacement gas is introduced into the discharge space S from the replacement gas introduction system 12 through the exhaust pipe 10 (step S7).

As the replacement gas introduced in this step S7, a gas not containing H ₂ O and CO ₂ is used. For example, an inert gas, a mixed gas of inert gas and hydrogen gas or oxygen gas, oxygen gas, nitrogen Various gases such as gas, fluorine gas, chlorine gas, mixed gas of nitrogen gas and hydrogen gas or oxygen gas, mixed gas of fluorine gas and hydrogen gas or oxygen gas, mixed gas of chlorine gas and hydrogen gas or oxygen gas Is used.

  Here, when a trace amount of hydrogen gas (about 3% or less) is mixed with the inert gas, the recovery effect of the phosphor layer 6 can be obtained, and a small amount of oxygen gas (about 20% or less) is added to the inert gas. When is mixed, an effect of improving the film quality of the protective layer (MgO layer) 3 can be obtained.

  The introduction pressure of the replacement gas in step S7 is set to, for example, about 1/100 to atmospheric pressure of the atmosphere.

  During the sealing process period P11, the surface of the glass frit of the sealing layer 7 is melted by heating, so that it is sealed to the front substrate 1 and between the back substrate 4 and the front substrate 1. The periphery of the discharge space S to be formed is sealed (step S8).

  After the sealing process period P11 has elapsed, the temperature of the baking furnace H is lowered from the temperature t11 to a temperature t12 (about 400 ° C.) that is equal to or lower than the melting temperature t2 (about 420 ° C.) of the glass frit of the sealing layer 7. When descending, this temperature t12 is maintained during the preset exhaust / baking process period P12.

  In the exhaust / baking process period P12, the front substrate 1 and the rear substrate 4 are heated (baked) at the temperature t12, and the secondary exhaust for exhausting the gas from the discharge space S is performed, so that the interior of the discharge space S is obtained. A vacuum is applied (step S9).

  Next, when the evacuation / baking process period P12 elapses, the temperature in the baking furnace H is lowered again, and the discharge gas is kept at a predetermined pressure (400) in the discharge space S in a state where the temperature is close to room temperature t3. (Step S10), and after the introduction of the discharge gas is completed, the exhaust and the exhaust pipe used for introducing the discharge gas are sealed by a burner or the like (step S11).

  Then, a drive pulse is applied between the pair of row electrodes X and Y of the front substrate 1 to generate a discharge for a predetermined time, thereby activating the protective layer 3 formed on the front substrate 1 and stabilizing the discharge. (Aging) is performed (step S12).

  With the display panel manufacturing method as described above, it is possible to obtain the same effect as that of manufacturing a display panel using a vacuum sealing furnace, and to solve the problems in the conventional manufacturing method.

That is, in the manufacturing process, after the heating is started, the temperature in the baking furnace H is maintained at a temperature t11 (about 425 ° C.) slightly exceeding the temperature t2 (about 420 ° C.) at which the glass frit of the sealing layer 7 starts to melt. In the sealing process period P11, the primary exhaust process S6 and the replacement gas introduction process S7 are performed before the sealing process S8 for sealing the discharge space S is completed, thereby filling the discharge space S with the atmosphere. And the impure gas released from the substrate side by the heating is discharged, the degassing from the protective layer (MgO layer) 3 is promoted, and the inner surface side of each substrate is H ₂ O, CO ₂ or the like under high temperature conditions. Therefore, it is possible to prevent the phosphor layer 6 from deteriorating, which can greatly improve the panel performance (discharge characteristics) of the display panel. Uninaru.

  The above manufacturing method can exert the above-mentioned effects without setting the exhaust / baking process period P12 to a long time or using a large-scale vacuum sealing apparatus. In addition, in the conventional manufacturing apparatus, Since it can be implemented with simple changes and modifications, the manufacturing cost will not increase significantly.

  Further, by adjusting the pressure of the replacement gas introduced into the discharge space S after the primary exhaust, the pressure in the discharge space S in the manufacturing process can be maintained at a desired pressure. It is possible to arbitrarily adjust the distance between 1 and the back substrate 4.

  When the primary exhaust is performed in the primary exhaust process S6 or when the replacement gas is exhausted in the secondary exhaust / baking process S9, the exhaust pump 11 is driven in advance so that the exhaust pipe 10 is evacuated. In addition, if the valve connecting the exhaust pump 11 and the exhaust pipe 10 is opened at the start of the step S6 and the step S9, the exhaust is performed all at once and the time for each step can be shortened. .

  FIG. 7 is a graph showing the relationship between the exhaust pressure and the voltage life of the PDP in the primary exhaust process S6.

As shown in FIG. 7, in the primary exhaust step S6, the lower the primary exhaust pressure, the longer the voltage life of the PDP. In particular, by setting the primary exhaust pressure to be 1 × 10 ⁻² Pa or less. The voltage life of the PDP can be greatly extended.

  FIG. 8 is a graph showing the relationship between the concentration of oxygen gas to be introduced and the accelerating voltage life of the PDP when oxygen gas is introduced as a replacement gas in the replacement gas introduction step S7.

  As shown in FIG. 8, in the replacement gas introduction step S7, the higher the concentration of oxygen gas introduced as replacement gas, the longer the voltage life of the PDP, and oxygen gas alone (concentration 100%) is introduced as replacement gas. As a result, the voltage life of the PDP can be maximized.

If the mixing ratio of O ₂ is increased, the acceleration voltage life of the panel is extended, but in this case, the initial characteristics of the panel may be deteriorated.

Therefore, in order to achieve both the acceleration voltage life and the initial characteristics of the panel, for example, it is desirable that the replacement gas is a mixed gas of N ₂ and O ₂ and the mixing ratio of O ₂ is 35% or less, preferably about 30%. .

  FIG. 9 is a diagram showing the relationship between the temperature change in the baking furnace and the process elapsed time in the second example of the embodiment of the display panel manufacturing method according to the present invention.

  In the manufacturing method of the first embodiment, the set temperature t12 in the baking furnace in the exhaust / baking process period P12 is set lower than the set temperature t11 in the sealing process period P11, whereas the second embodiment. In the manufacturing method of the display panel, the set temperatures in the respective baking furnaces H in the sealing process period P21 and the exhaust / baking process period P22 are both temperatures t2 at which the glass frit of the sealing layer 7 starts to melt. The temperature t21 (about 425 ° C.) slightly exceeding (420 ° C.) is maintained.

  That is, the front substrate 1 and the back substrate 4 are put into the baking furnace H in a state where they are overlapped with each other, and the heating in the baking furnace H is started, and the temperature in the baking furnace H is formed on the back substrate 4. When a temperature t21 (about 425 ° C.) slightly exceeding a temperature t2 (about 420 ° C.) at which the glass frit of the sealing layer 7 starts to soften is reached, a sealing process period P21 set in advance from that point, and During the exhaust / baking process period P22 following the sealing process period P21, the temperature in the baking furnace H is maintained at this temperature t21.

  Then, immediately after the start of the sealing process period P21, a primary exhaust process S6 from the discharge space S by driving the exhaust pump 11 is performed, and subsequently, a replacement gas introduction from the replacement gas introduction system 12 is performed. Step S7 and sealing step S8 are performed (see FIGS. 4 and 5).

  After the sealing process period P21, the secondary exhaust / baking process S9 is performed in the next exhaust / baking process period P22 while the temperature in the baking furnace H is maintained at the temperature t21.

  Furthermore, after the end of the exhaust / baking process period P22, the temperature in the baking furnace H is lowered to about the room temperature t3, and then the discharge gas introduction process S10 from the discharge gas introduction system 13 into the discharge space S and An exhaust pipe sealing step S11 and an aging step S12 are performed.

  Also in this example, the type of the replacement gas introduced in the replacement gas introduction step, and the relationship between the concentration when oxygen gas is introduced as the replacement gas and the acceleration voltage life of the PDP (FIG. 8) are: This is the same as in the case of the first embodiment.

  Further, the relationship between the exhaust pressure in the primary exhaust process and the voltage life of the PDP (FIG. 7) is the same as in the first embodiment.

Also in the PDP manufacturing method in this embodiment, as in the case of the first embodiment, in the display panel manufacturing process, the temperature in the baking furnace H is such that the glass frit of the sealing layer 7 begins to soften, t2 ( Before the sealing step S8 for sealing the discharge space S is completed in the sealing step period P11 maintained at a temperature t21 (about 425 ° C) slightly exceeding about 420 ° C), the primary exhaust step S6 and By performing the replacement gas introduction step S7, the impure gas discharged from the substrate side by heating and the atmosphere filling the discharge space S is discharged, and the degassing from the protective layer (MgO layer) 3 is promoted. while being, since the inner surface of each substrate under high temperature conditions is prevented from being exposed to impure gas such as H _{2 O,} CO _2, is prevented from phosphor layer 6 is deteriorated, depending on which , It becomes possible to achieve significant improvements in panel of the display panel performance (discharge characteristics).

  In the above embodiment, the temperature t21 in the baking furnace H maintained in the sealing process period P21 and the exhaust / baking process period P22 is equal to or slightly lower than the frit softening point temperature of the sealing layer 7 of the PDP. However, when the sealing layer 7 is formed of a crystalline frit, the temperature can be set higher than when it is formed of an amorphous frit.

  FIG. 10 is a diagram showing the relationship between the temperature change in the baking furnace and the process elapsed time in the third example of the embodiment of the display panel manufacturing method according to the present invention.

  In the first and second embodiments described above, the heating temperature is maintained at the softening start temperature of the sealing material during the sealing step, whereas the display panel manufacturing method in the third embodiment is overlapped. After the temperature in the baking furnace H into which the front substrate 1 and the back substrate 4 that have been introduced has reached the frit softening point temperature t2, it once falls to a temperature t31 (about 400 ° C.) lower than the frit softening point temperature t2. This temperature t31 is maintained during a predetermined primary exhaust / substitution gas introduction period P31.

  During the primary exhaust / substitution gas introduction period P31, a primary exhaust step S6 from the discharge space S driven by the exhaust pump 11 and a substitution gas introduction step S7 from the substitution gas introduction system 12 are performed ( (See FIGS. 4 and 5).

  At this time, before the primary exhaust step S6 and the replacement gas introduction step S7 are performed, the temperature in the baking furnace H once reaches the frit softening point temperature t2, and the surface of the sealing layer 7 that has started to soften is the front surface. Since the discharge space S between the front substrate 1 and the rear substrate 4 is sealed by being in close contact with the substrate 1, the primary exhaust and the replacement gas are reliably introduced without entering the discharge space S. Is called.

  After the end of the primary exhaust / substitution gas introduction period P31, the inside of the baking furnace H is raised to a sealing temperature t32 (about 450 ° C.) higher than the frit softening point temperature t2, and this sealing temperature t32 is a predetermined sealing step. During the period P32, the sealing step S8 is performed in the sealing step period P32, and the sealing layer 7 is completely sealed to the front substrate 1.

  After the sealing process period P32, the temperature in the baking furnace H is lowered again to the temperature t31, and this temperature t31 is maintained during the exhaust / baking process period P33. The secondary exhaust / baking step S9 is performed.

  The temperatures of the primary exhaust / substitution gas introduction period P31 and the exhaust / baking process period P33 need only be equal to or lower than the frit softening point, and need not be the same.

  Further, after the end of the exhaust / baking process period P33, the temperature in the baking furnace H is lowered to about room temperature t3, and thereafter, a discharge gas introduction process S10 from the discharge gas introduction system 13 into the discharge space S, And the sealing process S11 and the aging process S12 of the discharge space S are performed.

  Also in this example, the type of the replacement gas introduced in the replacement gas introduction step, and the relationship between the concentration when oxygen gas is introduced as the replacement gas and the acceleration voltage life of the PDP (FIG. 8) are: This is the same as in the case of the first embodiment.

  Further, the relationship between the exhaust pressure in the primary exhaust process and the voltage life of the PDP (FIG. 7) is the same as in the first embodiment.

The display panel manufacturing method in this embodiment also fills the discharge space S by performing the primary exhaust process S6 and the replacement gas introduction process S7 before the sealing process S8 in the sealing process period P32 is performed. The impure gas released from the substrate side due to the atmosphere and heating is exhausted, and degassing from the protective layer (MgO layer) 3 is promoted, and the inner surface side of each substrate is H ₂ O, CO under high temperature conditions. ₂ is prevented from being exposed to an impure gas such as _2, so that the phosphor layer 6 is prevented from deteriorating, and thereby the panel performance (discharge characteristics) of the display panel can be greatly improved. become.

  In this embodiment, when the temperature in the baking furnace H reaches the frit softening point temperature t2, the discharge space S between the front substrate 1 and the rear substrate 4 is sealed, and then the temperature of the baking furnace H decreases. As a result, the flow of the frit of the sealing layer 7 is suppressed, so that the primary exhaust and the introduction of the replacement gas can be performed stably.

  FIG. 11 is a diagram showing the relationship between the temperature change in the baking furnace and the process elapsed time in the fourth example of the embodiment of the display panel manufacturing method according to the present invention.

  In the third embodiment described above, the inside of the baking furnace H is raised to the sealing temperature t32 higher than the frit softening point temperature t2 after the primary exhaust / substitution gas introduction period P31, and is maintained at the sealing temperature t32. In this embodiment, the sealing process period P32 is set in the state, whereas in the primary exhaust / substitution gas introduction period P41 and the sealing process period P42, both the temperatures in the baking furnace H are the frit softening point temperature t2. The temperature is maintained at a lower temperature t41 (about 400 ° C.).

  That is, in this embodiment, after the temperature in the baking furnace H into which the front substrate 1 and the back substrate 4 that have been superposed has reached the frit softening point temperature t2, it falls to a temperature t41 that is lower than the frit softening point temperature t2. This temperature t41 is maintained for a predetermined primary exhaust / substitution gas introduction period P41 and the subsequent sealing process period P42 and exhaust / baking process period P43.

  During the primary exhaust / substitution gas introduction period P41, the primary exhaust step S6 from the discharge space S driven by the exhaust pump 11 and the substitution gas introduction step S7 from the substitution gas introduction system 12 are performed ( (See FIGS. 4 and 5).

  At this time, before the primary exhaust process S6 and the replacement gas introduction process S7 are performed, the temperature in the baking furnace H once reaches the frit softening point temperature t2, and the surface of the sealing layer 7 that has started to soften is the front surface. Since the discharge space S is sealed by being in close contact with the substrate 1, the primary exhaust and the replacement gas are reliably introduced without the atmosphere entering the discharge space S.

  After the end of the primary exhaust / substitution gas introduction period P41, the sealing layer 7 dissolved when the temperature in the baking furnace H reaches the frit softening point temperature t2 by the sealing process S8 during the sealing process period P42. Are completely sealed on the front substrate 1.

  Then, the secondary exhaust / baking step S9 is performed in the exhaust / baking step period P43 after the end of the sealing step P42.

  Further, after the end of the exhaust / baking process period P43, the temperature in the baking furnace H is lowered to almost normal temperature t3, and thereafter, a discharge gas introduction process S10 from the discharge gas introduction system 13 into the discharge space S, And the sealing process S11 and the aging process S12 of the discharge space S are performed.

  Also in this example, the type of the replacement gas introduced in the replacement gas introduction step, and the relationship between the concentration when oxygen gas is introduced as the replacement gas and the acceleration voltage life of the PDP (FIG. 8) are: This is the same as in the case of the first embodiment.

  Further, the relationship between the exhaust pressure in the primary exhaust process and the voltage life of the PDP (FIG. 7) is the same as in the first embodiment.

The display panel manufacturing method in this embodiment also fills the discharge space S by performing the primary exhaust process S6 and the replacement gas introduction process S7 before the sealing process S8 in the sealing process period P42 is performed. The impure gas released from the substrate side due to the atmosphere and heating is exhausted, and degassing from the protective layer (MgO layer) 3 is promoted, and the inner surface side of each substrate is H ₂ O, CO under high temperature conditions. ₂ is prevented from being exposed to an impure gas such as _2, so that the phosphor layer 6 is prevented from deteriorating, and thereby the panel performance (discharge characteristics) of the display panel can be greatly improved. become.

  In this embodiment, when the temperature in the baking furnace H reaches the frit softening point temperature t2, the discharge space S between the front substrate 1 and the rear substrate 4 is sealed, and then the temperature of the baking furnace H decreases. As a result, the flow of the frit of the sealing layer 7 is suppressed, so that the primary exhaust and the introduction of the replacement gas can be performed stably.

  FIG. 12 is a diagram showing the relationship between the temperature change in the baking furnace and the process elapsed time in the fifth example of the embodiment of the PDP manufacturing method according to the present invention.

  In the third embodiment described above, the degree of progress of the sealing process period P32, the temperature in the baking furnace H is lowered again to a temperature t31 (about 400 ° C.) lower than the frit softening point temperature t2, and this temperature t31 is maintained. In this state, the secondary exhaust / baking process S9 is performed in the next exhaust / baking process period P33. In this embodiment, the temperature in the baking furnace H decreases after the sealing process period P52 ends. Then, when the temperature is lowered, the temperature in the baking furnace H is lowered to the frit softening point temperature t2, and then the secondary exhaust is performed in the temperature lowering process.

  That is, after the temperature in the baking furnace H in which the front substrate 1 and the back substrate 4 that have been superimposed have reached the frit softening point temperature t2, the temperature t51 in which the temperature in the baking furnace H is lower than the frit softening point temperature t2. The temperature is lowered to (about 400 ° C.), and this temperature t51 is maintained during a predetermined primary exhaust / substitution gas introduction period P51.

  During the primary exhaust / substitution gas introduction period P51, a primary exhaust step S6 from the discharge space S driven by the exhaust pump 11 and a substitution gas introduction step S7 from the substitution gas introduction system 12 are performed ( (See FIGS. 4 and 5).

  At this time, before the primary exhaust step S6 and the replacement gas introduction step S7 are performed, the temperature in the baking furnace H once reaches the frit softening point temperature t2, and the surface of the sealing layer 7 that has started to soften is the front surface. Since the discharge space S between the front substrate 1 and the rear substrate 4 is sealed by being in close contact with the substrate 1, the primary exhaust gas and the replacement gas are reliably introduced without the atmosphere entering the discharge space S. Is called.

  After the end of the primary exhaust / substitution gas introduction period P51, the inside of the baking furnace H is raised to a sealing temperature t52 (about 450 ° C.) higher than the frit softening temperature t2, and the sealing temperature t52 is a predetermined sealing step. During the period P52, the sealing process S8 is performed in the sealing process period P52, and the sealing layer 7 is completely sealed to the front substrate 1.

  After the sealing process period P52 is finished, the temperature in the baking furnace H is lowered to about normal temperature t3, and after the temperature in the baking furnace H becomes substantially the frit softening point temperature t2 in this temperature lowering process, the exhaust gas is exhausted. Is started and a secondary exhaust process is performed.

  In this embodiment, the baking process is not performed.

  And after the temperature in the baking furnace H falls to substantially normal temperature t3, the discharge gas introduction process S10 from the discharge gas introduction system 13 into the discharge space S, the sealing process S11 of the discharge space S, and the aging process S12. Is done.

  Also in this example, the type of the replacement gas introduced in the replacement gas introduction step, and the relationship between the concentration when oxygen gas is introduced as the replacement gas and the acceleration voltage life of the PDP (FIG. 8) are: This is the same as in the case of the first embodiment.

  Further, the relationship between the exhaust pressure in the primary exhaust process and the voltage life of the PDP (FIG. 7) is the same as in the first embodiment.

The display panel manufacturing method in this embodiment also fills the discharge space S by performing the primary exhaust process S6 and the replacement gas introduction process S7 before the sealing process S8 in the sealing process period P52 is performed. The impure gas released from the substrate side due to the atmosphere and heating is exhausted, and degassing from the protective layer (MgO layer) 3 is promoted, and the inner surface side of each substrate is H ₂ O, CO under high temperature conditions. ₂ is prevented from being exposed to an impure gas such as _2, so that the phosphor layer 6 is prevented from deteriorating, and thereby the panel performance (discharge characteristics) of the display panel can be greatly improved. become.

It is sectional drawing which shows the general structure of a display panel. It is process explanatory drawing which shows the manufacturing method of the conventional display panel. It is a figure which shows the temperature change in the baking furnace in the conventional manufacturing method. It is process explanatory drawing which shows the 1st Example in embodiment of the manufacturing method of the display panel by this invention. It is a figure which shows the temperature change in the baking furnace in the example. It is a schematic block diagram of the baking furnace used for the manufacturing method of the example. It is a figure which shows the relationship between the primary exhaust pressure and the voltage lifetime of PDP in the manufacturing method of the display panel by this invention. It is a figure which shows the relationship between the oxygen gas concentration introduce | transduced as replacement gas in the manufacturing method of the display panel by this invention, and the voltage life of PDP. It is a figure which shows the 2nd Example in embodiment of the manufacturing method of the display panel by this invention. It is a figure which shows the 3rd Example in embodiment of the manufacturing method of the display panel by this invention. It is a figure which shows the 4th Example in embodiment of the manufacturing method of the display panel by this invention. It is a figure which shows the 5th Example in embodiment of the manufacturing method of the display panel by this invention.

Explanation of symbols

1 ... Front substrate (substrate)
3 ... Protective layer 4 ... Back substrate (substrate)
7 ... Sealing layer 10 ... Exhaust pipe 11 ... Exhaust pump 12 ... Replacement gas introduction system 13 ... Discharge gas introduction system t2 ... Frit softening point temperature (sealing material softening start temperature)
P11, P21, P32, P42, P52
... Sealing process period P31, P41, P51 ... Primary exhaust / substitution gas introduction period P12, P22, P33, P43 ... Exhaust / baking process period

Claims (16)

By heating a sealing material positioned so as to surround an internal space between a pair of substrates opposed to each other with a predetermined interval, and softening the sealing material at a predetermined temperature to be welded to the substrate In a method for manufacturing a display panel for sealing an internal space between a pair of substrates,
After the heating temperature of the sealing material reaches the softening start temperature of the sealing material, before the sealing step of sealing the internal space between the pair of substrates with the sealing material is performed, the interior between the pair of substrates A display panel manufacturing method comprising: a primary exhaust process for exhausting air from a space, and a process of introducing a replacement gas into an internal space after the primary exhaust process.   In the primary exhaust process, the replacement gas introduction process, and the sealing process, the heating temperature of the sealing material is maintained at the softening start temperature of the sealing material or higher than the softening start temperature in the vicinity of the softening start temperature. The method for manufacturing a display panel according to claim 1, wherein the display panel is performed in a state where   After the primary exhaust step, the replacement gas introduction step, and the sealing step, the sealing material was sealed in a state where the heating temperature of the sealing material was maintained at a predetermined temperature lower than the softening start temperature of the sealing material. The method for manufacturing a display panel according to claim 2, wherein a secondary exhaust process from the internal space between the pair of substrates is performed.   After the primary exhaust process, the replacement gas introduction process, and the sealing process are performed, the heating temperature of the sealing material is maintained at substantially the same temperature as the primary exhaust process, the replacement gas introduction process, and the sealing process. The method for manufacturing a display panel according to claim 2, wherein a secondary exhaust process from the internal space between the pair of sealed substrates is performed in a state where the substrate is sealed.   The primary evacuation step and the replacement gas introduction step are performed in a state where the heating temperature of the sealing material reaches a softening start temperature of the sealing material and is maintained at a predetermined temperature lower than the softening start temperature of the sealing material. A method for manufacturing a display panel according to claim 1.   6. The sealing process is performed in a state where the heating temperature of the sealing material is maintained at a predetermined temperature higher than the softening start temperature of the sealing material after the primary exhaust process and the replacement gas introducing process are performed. The manufacturing method of the display panel as described in any one of.   The display according to claim 6, wherein after the sealing step is performed, the secondary exhaust step is performed in a state where the heating temperature of the sealing material is maintained at a predetermined temperature lower than the softening start temperature of the sealing material. Panel manufacturing method.   6. The sealing process is performed in a state where the heating temperature of the sealing material is maintained at a predetermined temperature lower than the softening start temperature of the sealing material after the primary exhaust process and the replacement gas introducing process are performed. The manufacturing method of the display panel as described in any one of.   The display according to claim 8, wherein after the sealing step is performed, the secondary exhaust step is performed in a state where the heating temperature of the sealing material is maintained at a predetermined temperature lower than the softening start temperature of the sealing material. Panel manufacturing method.   After the sealing step is performed, the heating temperature of the sealing material is lowered, and in the process in which the heating temperature is lowered, secondary exhaust is performed after the temperature becomes lower than the softening start temperature of the sealing material. The manufacturing method of the display panel of Claim 6 with which a process is performed.   The method for manufacturing a display panel according to claim 1, wherein the replacement gas contains hydrogen gas.   The method for manufacturing a display panel according to claim 11, wherein a ratio of the hydrogen gas is 3% or less of a replacement gas.   The display panel manufacturing method according to claim 1, wherein the replacement gas contains oxygen gas.   The method for manufacturing a display panel according to claim 13, wherein a ratio of the oxygen gas is 20 percent or less of a replacement gas. The method for manufacturing a display panel according to claim 1, wherein an exhaust pressure in the primary exhaust process is 1 × 10 ⁻² Pascal or less.   The method for manufacturing a display panel according to claim 1, wherein a replacement gas having an oxygen gas concentration of 100 percent is introduced in the replacement gas introduction step.

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