WO2012098847A1

WO2012098847A1 - Method of manufacturing plasma display panel

Info

Publication number: WO2012098847A1
Application number: PCT/JP2012/000198
Authority: WO
Inventors: 憲輝前田; 修種田; 沖川　昌史
Original assignee: パナソニック株式会社
Priority date: 2011-01-20
Filing date: 2012-01-16
Publication date: 2012-07-26
Also published as: JP2012151023A

Abstract

This method of manufacturing a plasma display panel comprises manufacturing a front-face panel (50), manufacturing a back-face panel (60) that has arranged thereon partition walls (11) for partitioning discharge cells, arranging the front-face panel and the back-face panel so as to face each other, sealing the periphery of the front-face panel and the back-face panel with a sealing member, and evacuating the discharge cells. A conjoining member is arranged at the apexes of the partition walls. The sealing temperature (T0) upon sealing the surroundings of the front-face panel and the back-face panel with the sealing member, the yield temperature (T1) of the conjoining member, the yield temperature (T2) of the sealing member, and the temperature (T3) at which pressure reduction in the discharge cells is to be started have relationships of T0 - T1 ≥ 30°C, T1 < T2 <T0, and T1 < T3 ≤ T0.

Description

Method for manufacturing plasma display panel

The technology disclosed herein relates to a method for manufacturing a plasma display panel used for a display device or the like.

In recent years, a thin glass substrate has been used as a glass substrate used for a front panel and a rear panel of a plasma display panel (hereinafter referred to as PDP). In addition, the width of the partition wall is narrowed along with the higher definition of the PDP. In such PDPs, reduction of mechanical strength has become a problem.

On the other hand, the mechanical strength is improved by bringing the front panel and the rear panel into close contact with each other so that no gap is generated. Specifically, a technique for bonding the upper surface of the partition wall of the rear panel to the front panel is known (see, for example, Patent Document 1).

JP-A-11-204040

The manufacturing method of the PDP is to manufacture a front panel, to manufacture a back panel with partition walls for partitioning discharge cells, to place the front panel and the back panel facing each other, and to seal the periphery of the front panel and the back panel. Sealing with an attachment member, and exhausting the inside of the discharge cell. A coupling member is arranged on the top of the partition wall, and the sealing temperature T0 when the periphery of the front panel and the rear panel is sealed with the sealing member, the yielding point T1 of the coupling member, the yielding point T2 of the sealing member, and the discharge cell. The temperature T3 at which the pressure reduction starts is in a relationship of T0−T1 ≧ 30 ° C., T1 <T2 <T0, and T1 <T3 ≦ T0.

FIG. 1 is a perspective view showing the structure of the PDP according to the present embodiment. FIG. 2 is a cross-sectional view showing the discharge cell structure of the PDP according to the present embodiment. FIG. 3 is a schematic diagram illustrating a configuration of a main part of the PDP according to the present embodiment. FIG. 4 is a manufacturing process diagram of the PDP according to the present embodiment. FIG. 5 is a diagram illustrating an example of a temperature profile in the sealing process, the exhaust process, and the discharge gas supply process in the manufacturing process of the PDP according to the present embodiment. FIG. 6 is a first schematic diagram showing the configuration of the main part of the PDP in the manufacturing process of the PDP according to the present embodiment. FIG. 7 is a second schematic diagram showing the configuration of the main part of the PDP in the manufacturing process of the PDP according to the present embodiment. FIG. 8 is a plan view seen from the front plate side showing the configuration of the image display unit of the PDP according to the present embodiment. FIG. 9 is a diagram showing the relationship between the bonding area, bonding strength, and driving voltage of the PDP according to the present embodiment. FIG. 10 is a diagram illustrating an example of a temperature profile and a pressure profile in the sealing process and the exhaust process in the manufacturing process of the PDP according to the present embodiment.

The PDP 100 according to the present embodiment is an AC surface discharge type PDP.

[Front panel 50]
As shown in FIGS. 1 and 2, a plurality of strip-shaped display electrodes 4 and black stripes (light-shielding layers) 5 each made up of a scanning electrode 2 and a sustaining electrode 3 are parallel to each other on a glass front substrate 1. Arranged in columns. Scan electrode 2 and sustain electrode 3 are arranged in a repeating pattern of scan electrode 2 -sustain electrode 3 -sustain electrode 3 -scan electrode 2.

The scan electrode 2 is a bus made of silver (Ag) or the like provided on a transparent electrode made of a conductive metal oxide such as indium tin oxide (ITO), tin dioxide (SnO ₂ ), or zinc oxide (ZnO). Including electrodes.

The sustain electrode 3 includes a bus electrode made of Ag or the like provided on a transparent electrode made of a conductive metal oxide such as ITO, SnO ₂ , or ZnO.

A dielectric layer 6 serving as a capacitor is formed on the front substrate 1 so as to cover the display electrode 4 and the light shielding layer 5.

The dielectric layer 6 is made of a dielectric material containing silica fine particles having a particle size of 100 nm or less. The dielectric layer 6 has a thickness of 20 μm or less and a relative dielectric constant of 2 or more and 4 or less. For example, a dielectric material ink in which silica fine particles having a particle size of 8 nm to 20 nm and a relative dielectric constant of about 4 are dispersed in a siloxane polymer organic solvent is used. Alternatively, a dielectric material ink in which silica fine particles such as colloidal silica having a particle size of 8 nm to 20 nm and a relative dielectric constant of about 4 is dispersed in an aqueous solution is used. The dielectric material ink is applied on the front substrate 1 by a die coating method or the like so as to cover the display electrode 4 and the light shielding layer 5. Thereafter, a dielectric layer 6 having a thickness of 20 μm or less and a relative dielectric constant of 2 or more and 4 or less is formed through drying and firing.

A protective layer 7 made of magnesium oxide (MgO) or the like is formed on the surface of the dielectric layer 6.

The front panel 50 includes a front substrate 1, display electrodes 4, a light shielding layer 5, a dielectric layer 6, and a protective layer 7. The light shielding layer 5 may be omitted.

[Rear panel 60]
As shown in FIGS. 1 and 2, a plurality of data electrodes 9 made of a conductive material mainly composed of Ag parallel to each other are arranged on a glass back substrate 8. A base dielectric layer 10 is provided so as to cover the data electrode 9. On the base dielectric layer 10, a grid-like partition wall 11 is disposed. Red, green, and blue phosphor layers 12 are provided on the surface of the base dielectric layer 10 and the side surfaces of the partition walls 11. The partition wall 11 includes a vertical partition wall 11 a disposed in parallel with the data electrode 9 and a horizontal partition wall 11 b formed in a direction intersecting with the data electrode 9.

The back panel 60 includes a back substrate 8, data electrodes 9, a base dielectric layer 10, barrier ribs 11 and a phosphor layer 12.

[PDP100]
The front panel 50 and the back panel 60 are arranged to face each other so that the scan electrodes 2 and the sustain electrodes 3 and the data electrodes 9 are three-dimensionally crossed. The peripheral portions of the front panel 50 and the back panel 60 are hermetically sealed by a sealing member made of glass frit or the like. A discharge gas such as neon (Ne) and xenon (Xe) is sealed in a discharge space 13 inside the sealed PDP 100 at a pressure of 53 kPa to 80 kPa. Here, a discharge cell is formed at a portion where scan electrode 2 and sustain electrode 3 and data electrode 9 face each other. The discharge cell will be described in detail later.

In the present embodiment, the discharge gas mixed so that Xe is contained at 15% or more and 30% or less is enclosed in the discharge space 13.

As shown in FIG. 3, the thickness of the bus electrode in the display electrode 4 is about 5 μm. When the film thickness of the dielectric layer 6 is 20 μm or less, the surfaces of the dielectric layer 6 and the protective layer 7 are raised by the step of the display electrode 4. That is, irregularities are formed on the surface of the front panel 50 so as to correspond to the display electrodes 4. In FIG. 3, the protective layer 7 is omitted.

When the PDP 100 is configured by superimposing the front panel 50 and the rear panel 60 on which irregularities are formed, a gap is formed between the vertical partition walls 11 a formed in parallel to the data electrodes 9 and the front panel 50. The mechanical strength of the PDP 100 decreases due to the gap.

Therefore, in the present embodiment, as shown in FIG. 3, a bonding layer 20 made of a glass material for bonding to the front panel 50 is provided at least on the uppermost portion of the vertical partition wall 11a. The bonding layer 20 has a yield point lower than a sealing temperature when the front panel 50 and the back panel 60 are sealed with a glass frit as a sealing member. Further, the bonding layer 20 has a softening point equal to or higher than the sealing temperature. Further, the bonding layer 20 is made of a glass material containing Bi. Note that the bonding layer 20 may be provided not only on the vertical barrier ribs 11a but also on the horizontal barrier ribs 11b.

In the present embodiment, when the front panel 50 and the back panel 60 are sealed with a glass frit that is a sealing member, a sealing temperature that is higher than the yield point of the glass material constituting the bonding layer 20 and lower than the softening point. Maintained. At this time, the bonding layer 20 is bonded to the front panel 50 by applying pressure uniformly over the entire surface of the front panel 50 and the back panel 60. Specifically, when the front panel 50 and the back panel 60 are sealed with the sealing member, the pressure between the front panel 50 and the back panel 60 is reduced to cover the entire area of the front panel 50 and the back panel 60. It is possible to apply pressure uniformly.

[Production of PDP 100]
As shown in FIG. 4, the PDP according to the present embodiment is manufactured by a front panel creation process, a back panel creation process, a frit coating process, a sealing process, an exhaust process, and a discharge gas supply process.

In the frit application process, a glass frit as a sealing member is applied to the outside of the image display area of the back panel 60. Thereafter, the back panel 60 is temporarily fired at a temperature of about 350 ° C. in order to remove the resin component of the glass frit.

In the sealing step, the front panel 50 and the rear panel 60 are arranged to face each other so as to form a discharge space. The periphery of the front panel 50 and the back panel 60 is sealed with a sealing member.

In the exhaust process, the gas in the discharge space 13 is exhausted to a vacuum.

In the discharge gas supply process, a discharge gas mainly containing Ne and Xe is supplied to the exhausted discharge space 13.

As shown in FIG. 5, in the sealing step, the temperature is raised from the softening point to the sealing temperature during a period in which the temperature is raised from room temperature to the softening point of the glass frit as the sealing member (period 1), and held for a certain period of time. After that, it has a period (period 2) in which it is lowered to the softening point. The exhaust process has a period (period 3) in which the temperature is lowered to room temperature after being held at a temperature near or slightly lower than the softening point temperature for a certain time. The discharge gas supply step has a period (period 4) in which the discharge gas is supplied to the discharge space after being lowered to room temperature.

The yield point of the glass material is considered to be the temperature at which expansion stops apparently in the thermal expansion curve. Specifically, a temperature corresponding to a viscosity of about 10 ¹⁰ to 10 ¹¹ dPa · s is regarded as a yield point.

The softening point of the glass material is a temperature at which the glass begins to be significantly softened and deformed by its own weight. Specifically, a temperature corresponding to a viscosity of about 10 ^7.6 dPa · s is regarded as the softening point. The yield point and softening point of the glass frit in the present embodiment will be described later.

Further, the sealing temperature is a temperature at which the front panel 50 and the rear panel 60 are sealed by the glass frit that is a sealing member. The sealing temperature in the present embodiment will be described later.

As shown in FIG. 6, the back panel 60 has a data electrode 9, a base dielectric layer 10, and a grid-like partition wall 11 on a glass back substrate 8. The partition wall 11 is formed in a cross-beam shape by an exposure / development process after a glass material containing a photosensitive resin is applied on the underlying dielectric layer 10. Thereafter, the photosensitive resin and the like are burned through a baking process. In addition, a bonding layer 20 made of a glass material containing Bi is provided on the top of the vertical partition wall 11a.

Here, the glass material constituting the bonding layer 20 has a yield point that is lower than the sealing temperature and a softening point that is higher than the sealing temperature. Moreover, the glass material used for the partition 11 has a yield point and a softening point that are equal to or higher than the sealing temperature.

In the PDP 100 according to the present embodiment, the bonding layer 20 is bonded to the front panel 50 as shown in FIG.

The sealing member is preferably a glass frit mainly composed of bismuth oxide or vanadium oxide. As the glass frit mainly composed of bismuth oxide, for example, Bi ₂ O ₃ —B ₂ O ₃ —RO—MO system (where R is any one of Ba, Sr, Ca and Mg, and M is Any one of Cu, Sb, and Fe)) and a filler made of an oxide such as Al ₂ O ₃ , SiO ₂ , and cordierite can be used. In addition, as a frit mainly composed of vanadium oxide, for example, a filler made of an oxide such as Al ₂ O ₃ , SiO ₂ , cordierite or the like is added to a V ₂ O ₅ —BaO—TeO—WO glass material. Can be used.

As a material for the bonding layer 20, glass frit containing bismuth oxide is desirable. As the glass frit containing bismuth oxide, for example, Bi ₂ O ₃ —B ₂ O ₃ —ZnO—SiO ₂ —RO glass powder is used. For example, a photosensitive paste can be manufactured using a glass frit containing bismuth oxide. When the photosensitive paste is used, a desired shape can be obtained by exposure and development after the photosensitive paste is applied onto the partition wall 11. As another example, a printing paste can be manufactured using Bi ₂ O ₃ —B ₂ O ₃ —ZnO—SiO ₂ —RO glass powder. When a printing paste is used, a desired shape can be obtained by silk printing on the partition wall 11. When a glass material containing bismuth oxide, for example, Bi ₂ O ₃ —B ₂ O ₃ —ZnO—SiO ₂ —RO glass powder is used, the yield point temperature of the glass material is 487 ° C. to 489 ° C. The softening point temperature is about 530 ° C.

Next, the reason why the glass material constituting the bonding layer 20 has a yield point lower than the sealing temperature and a softening point higher than the sealing temperature will be described.

Sealing (adhesion) between glass substrates is generally performed at a temperature higher than the softening point temperature of the sealing member. However, when bonding is performed at a temperature higher than the softening point temperature of the glass material constituting the bonding layer 20 in the display region of the PDP 100, the glass material is in a so-called softening flow region. In other words, conventionally, there has been a problem that the discharge voltage increases or the luminance decreases due to the glass material flowing into the discharge space 13 or the increase in the amount of gas released from the bonding layer 20.

Therefore, as a result of investigations by the present inventors, by applying a uniform pressure over the entire surface of the front panel 50 and the back panel 60 during bonding, the temperature is higher than the yield point of the glass material constituting the bonding layer 20. It was found that it can be bonded. In other words, the glass material constituting the bonding layer 20 could be stably bonded without causing a problem such as a voltage increase or a luminance decrease in a so-called sintered region not less than the yield point and not more than the softening point.

According to the present embodiment, the front panel 50 and the back panel 60 are bonded by the bonding layer 20. That is, the front panel 50 and the back panel 60 can be brought into close contact so that no gap is generated. Therefore, the strength of the PDP 100 can be improved.

[Adhesion area of front panel 50 and rear panel 60]
The adhesion area in the bonding layer 20 between the front panel 50 and the back panel 60 in the present embodiment will be described. As shown in FIG. 8, the scan electrodes 2 and the sustain electrodes 3 are alternately arranged in the row direction so as to be adjacent to each other with a discharge gap in each line of the matrix display. Further, the discharge cell 51 is a rectangular region centered on a portion partitioned by the plurality of vertical barrier ribs 11a and the plurality of horizontal barrier ribs 11b and perpendicular to the display electrodes 4 and the data electrodes 9. The discharge cell 51 is a unit light emitting region in the PDP 100.

A non-discharge region 52 is formed between adjacent discharge cells 51. In the region of the front panel 50, black stripes 5 for improving the contrast are formed. As shown in FIG. 8, one discharge cell 51 is a region partitioned by a one-dot chain line.

In this embodiment, when the area of the discharge cell 51 is defined as S, the area where the front panel 50 and the back panel 60 are bonded to each other in the bonding layer 20 is 10% to 30% with respect to S. preferable. As shown in FIG. 8, the bonded area is the bonded area 53. In FIG. 8, the adhesion region 53 is shown only around the discharge cell 51 defined by the one-dot chain line. However, the adhesion region 53 is also present in the other adjacent discharge cells 51 as well.

Let R be the bonding area between the front panel 50 and the back panel 60 in the region of the discharge cell 51. As shown in FIG. 9, it can be seen that the adhesive strength between the front panel 50 and the back panel 60 increases linearly according to the adhesion area. It has been confirmed that the mechanical strength of the PDP 100 increases according to the adhesive strength.

However, it was found that in the region where the R / S is 10% or less, adhesion peeling occurs due to insufficient adhesion strength against vibration during the conveyance process in the manufacturing stage. Discharge characteristics differ between the state in which the front panel 50 and the partition 11 are bonded to isolate each discharge cell, and the state in which there is a gap between adjacent discharge cells without bonding. That is, when partial peeling occurs in the surface of the PDP 100 as described above, the voltage characteristics are different in the surface, resulting in a display defect.

In addition, as shown in FIG. 9, it has been clarified that when the bonding area exceeds 30% in order to increase the bonding strength, the sustain voltage required for driving increases rapidly. This is considered to be due to the fact that the separation between adjacent discharge cells proceeds due to the increase in the adhesion area, and sufficient exhaust cannot be performed in the exhaust process. The inventors have found that there is an optimum range for the bonding area. The adhesion area is preferably between 10% and 30%.

[Details of sealing process and exhaust process]
The sealing process and exhaust process in the present embodiment will be described. In FIG. 10, the temperature profile of the sealing process and the exhaust process is shown by a solid line. The pressure profile inside the PDP 100 is indicated by a broken line.

In the present embodiment, the sealing temperature (T0), the yield point temperature (T1) of the glass material constituting the bonding layer 20, the yield point (T2) of the glass frit of the sealing member, and the decompression start temperature (T3). Relationships are defined. That is, T0, T1, T2, and T3 have the following relationship. T0−T1 ≧ 30 ° C., T1 <T2 <T0, T1 <T3 ≦ T0. By satisfying the above relationship, adhesion between the bonding layer 20 and the front panel 50 can be further strengthened. FIG. 10 shows a case where T3 = T0.

The method for measuring the yield point of the bonding layer 20 will be described. First, a sample substrate a is prepared in which MgO having the same configuration as that of the protective film 7 is deposited on a raw glass on which no component is provided. A sample substrate b having the same configuration as that of the back panel 60 is prepared. Each of the sample substrate a and the sample substrate b is cut out so as to be a square having a side of 50 mm. Next, it arrange | positions so that MgO of the sample board | substrate a and the coupling layer 20 of the sample board | substrate b may contact. Next, a constant load is applied from both sides of the material substrate a and the material substrate b in the heating furnace. In this state, the relationship between the amount of displacement between the two sample substrates and the temperature is measured. The temperature at which the displacement changes from increasing to decreasing is the yield point temperature (T1). The yield point temperature is calculated by calculating the slope of the tangent near the inflection point in the relationship between the displacement and the temperature.

Next, the experimental results that serve as the basis for the above temperature range will be described. Table 1 shows the relationship between T0 and T1.

All the PDPs 100 used for evaluation have the bonding layer 20. The bonding layer 20 has five conditions. That is, T1 was fixed at 475 ° C. T0 is five conditions of 490 ° C. (sample 1), 495 ° C. (sample 2), 500 ° C. (sample 3), 505 ° C. (sample 4) and 510 ° C. (sample 5). Evaluation items are a steel ball drop test and a differential pressure test.

The steel ball drop test is a test in which a 500 g steel ball is dropped onto the PDP 100 at different heights. The height at which the bonding layer 20 peels off and the PDP 100 breaks is measured by the energy of the steel balls falling.

The differential pressure test is a test in which the pressure in the chamber is reduced while the PDP device installed in the chamber is lit. The PDP device has a configuration in which a chassis, a circuit board, and the like are connected to the PDP 100. At this time, the differential pressure P1-P2 when the coupling layer 20 peels off and the lighting state changes is measured with respect to the gas pressure P1 and the chamber internal pressure P2 inside the PDP 100. If the differential pressure is large, the bonding layer 20 adheres the front panel 50 and the back panel 60 more firmly.

As a result, as shown in Table 1, it was found that the steel ball drop test and the differential pressure test showed good results by setting the sealing temperature under the condition of T0−T1 ≧ 30 ° C.

Table 2 shows the relationship between T1 and T2.

All the PDPs 100 used for evaluation have the bonding layer 20. The bonding layer 20 has two rights. That is, T1 was fixed at 475 ° C. T0 was fixed at 505 ° C. T2 is two conditions of 470 ° C. (sample 6) and 490 ° C. (sample 7). The evaluation item is a package drop test.

The package drop test is a test in which the PDP device is dropped from a predetermined height in the shipping state. The shipping state is a state in which the PDP device is wrapped with a protective material such as polystyrene foam and further packed with cardboard. At this time, chipping may occur in the partition wall due to the impact of dropping. Depending on the degree of chipping, the discharge cell may become unlit. In the present embodiment, the total number of unlit lamps of 10 sets of 42-inch diagonal PDP devices was measured.

As shown in Table 2, under the condition of T2 = 490 ° C., the number of non-lights can be reduced as compared with the condition of T2 = 470 ° C. That is, by setting T1 <T2 <T0, the occurrence of non-lighting of the PDP device is suppressed. Furthermore, the reliability of the PDP is improved.

Furthermore, T3 is preferably higher than T1. This is because a substantially uniform pressure can be applied to the entire surface of the PDP 100 by reducing the pressure inside the PDP 100. Since the viscosity of the bonding layer 20 is lowered in this state, the bonding layer 20 and the front panel 50 are bonded uniformly. That is, by setting T1 <T3 ≦ T0, the adhesion between the front panel 50 and the back panel 60 can be made in-plane uniform.

The PDP 100 having the protective layer 7 containing MgO and calcium oxide (CaO) was found to have a withstand voltage 1.2 times higher in the differential pressure test. That is, even if the structure of the coupling layer 20 is the same, it means that the breakdown voltage is 1.2 times. This is presumably because the reaction between the bonding layer 20 and the protective film 7 was promoted by the protective film 7 containing calcium (Ca).

[Summary]
The manufacturing method of the PDP 100 according to the present embodiment includes manufacturing the front panel 50, manufacturing the back panel 60 with the partition walls partitioning the discharge cells, disposing the front panel 50 and the back panel 60 facing each other, The periphery of the front panel 50 and the back panel 60 is sealed with a sealing member, and the inside of the discharge cell is evacuated. A coupling member is arranged on the top of the partition wall, and a sealing temperature T0 when the periphery of the front panel 50 and the back panel 60 is sealed by the sealing member, a yielding point T1 of the coupling member, a yielding point T2 of the sealing member, and The temperature T3 at which pressure reduction in the discharge cell is started has a relationship of T0−T1 ≧ 30 ° C., T1 <T2 <T0, and T1 <T3 ≦ T0. According to the above method, the mechanical strength of the PDP 100 can be improved.

Further, the PDP 100 according to the present embodiment includes a front panel 50 and a rear panel 60 provided to face the front panel 50 and having partition walls that partition discharge cells. The front panel 50 and the back panel 60 are sealed at the periphery, and the front panel 50 and the back panel 60 are bonded to each other at the upper part of the partition wall. The area where the discharge cell is bonded to the front panel 50 or the back panel 60 is 10% or more and 30% or less. According to the above configuration, it is possible to suppress the occurrence of defects due to peeling or the like in the manufacturing process / market. Further, it is possible to realize the PDP 100 that suppresses an increase in driving voltage and has high mechanical strength.

The technique disclosed herein is useful for realizing a plasma display device with improved mechanical strength.

DESCRIPTION OF SYMBOLS 1 Front substrate 2 Scan electrode 3 Sustain electrode 4 Display electrode 6 Dielectric layer 8 Rear substrate 9 Data electrode 10 Base dielectric layer 11 Partition 11a Vertical partition 11b Horizontal partition 12 Phosphor layer 13 Discharge space 20 Coupling layer 50 Front panel 51 Discharge Cell 52 Non-discharge area 53 Adhesion area 60 Rear panel 100 PDP

Claims

Manufacturing the front panel,
Manufacturing a rear panel with barrier ribs separating discharge cells;
Disposing the front panel and the back panel opposite to each other;
Sealing the periphery of the front panel and the back panel with a sealing member;
Exhausting the inside of the discharge cell,
A coupling member is arranged on the top of the partition wall,
The sealing temperature T0 when the periphery of the front panel and the back panel is sealed with a sealing member, the yield point T1 of the coupling member, the yield point T2 of the seal member, and the pressure reduction in the discharge cell are started. The temperature T3 to be satisfied is T0−T1 ≧ 30 ° C., T1 <T2 <T0, and T1 <T3 ≦ T0.
A method for manufacturing a plasma display panel.