JP2012064370A - Plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a plasma display panel improved in panel strength.SOLUTION: In a plasma display panel of the present invention, a front panel and a back panel which has a barrier rib partitioning discharge cells are arranged to face each other and sealed at peripheries. The front panel and the back panel are bonded at an upper part of the barrier rib, and the bonded area accounts for 10% or more and 30% or less of an area formed by projecting a discharge space on the front panel or the back panel.

Description

  The present invention relates to a plasma display panel as a display device.

  Since plasma display panels (hereinafter referred to as PDP) can achieve high definition and large screen, 65-inch class televisions have been commercialized. In recent years, PDP has been applied to high-definition televisions having more than twice the number of scanning lines as compared with the conventional NTSC system, and PDP containing no lead component is required in consideration of environmental problems.

  A PDP basically includes a front panel and a back panel. The front panel includes a glass substrate of sodium borosilicate glass by a float method, a display electrode composed of a striped transparent electrode and a bus electrode formed on one main surface of the glass substrate, and a display electrode A dielectric layer that covers and acts as a capacitor, and a protective layer made of magnesium oxide (MgO) formed on the dielectric layer. On the other hand, the back panel includes a glass substrate, striped data electrodes formed on one main surface thereof, a base dielectric layer covering the data electrodes, a partition formed on the base dielectric layer, It is comprised with the fluorescent substance layer which light-emits each of red, green, and blue formed between the partition walls.

  The front panel and the rear panel are arranged to face each other so that the display electrode and the data electrode intersect with each other, and a sealed space is formed by sealing the outer peripheral portion. In the sealed space, xenon (Xe ) / Neon (Ne) and discharge gas such as xenon (Xe) / neon (Ne) / helium (He).

  In the PDP configured as described above, a discharge cell serving as a minimum unit of light emission is formed in each region where the display electrode on the front panel and the data electrode on the rear panel intersect.

  In recent years, in a PDP, a thin glass substrate has been used as a glass substrate used for a front panel and a back panel, and as the width of a partition wall has been reduced along with the increase in definition. Therefore, a decrease in panel strength has become a problem.

  As an example of means for solving such a problem, it is known that the panel strength can be improved by bringing the front panel and the rear panel into close contact so that no gap is generated. It is known that the upper surface of a partition wall of a panel is bonded to a front panel (see, for example, Patent Document 1).

JP-A-11-204040

  However, when the front plate and the rear plate are bonded to each other, if a certain bonding area is not ensured, peeling of the adhesive in the panel manufacturing process / transporting process and a display defect accompanying this will occur. Further, if the adhesion area is too large, there is a problem that exhaustion at the time of sealing becomes insufficient and various voltages required for driving increase.

  An object of the present invention is to solve these problems and to realize a high quality display image PDP with improved panel strength.

  In order to achieve the above object, the present invention provides a plasma display panel in which a front panel and a rear panel having barrier ribs for partitioning discharge cells are arranged to face each other and sealed around the front panel. The back panel is bonded to the upper part of the barrier rib, and the bonded area is 10% or more and 30% or less with respect to the area where the discharge space is projected on the front panel or the back panel. And Here, the partition wall has a bonding layer, and the bonding layer preferably contains Bi. In addition, the yield point of the material constituting the bonding layer is preferably equal to or higher than the sealing temperature.

  According to the present invention, the front panel and the back panel are bonded by the bonding layer, whereby the front panel and the back panel can be brought into close contact so as not to generate a gap, and the strength of the panel is improved. Can do.

The perspective view which shows the structure of PDP in embodiment of this invention Sectional drawing which shows the discharge cell structure of the PDP Schematic diagram showing the fine structure of the dielectric layer of the front panel of the PDP Schematic for explaining the main configuration of the PDP Process diagram for explaining the manufacturing process of the PDP The figure which shows an example of the temperature profile of a sealing process, an exhaust process, and a discharge gas supply process in the manufacturing process of the PDP Schematic for explaining the main part configuration in the manufacturing process of the PDP Schematic for explaining the main part configuration in the manufacturing process of the PDP The top view seen from the front-plate side which shows the structure of the image display part of the PDP The figure which shows the relationship between the adhesion area of the same PDP, adhesion strength, and drive voltage

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

  FIG. 1 is a perspective view showing a structure of a PDP according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a discharge cell structure. In the PDP, a large number of discharge cells are formed between a front panel and a back panel arranged to face each other.

  In the front panel, a plurality of pairs of display electrodes including a pair of scanning electrodes 2 and sustaining electrodes 3 are formed on a glass front substrate 1 in parallel with each other. Scan electrode 2 and sustain electrode 3 are formed in a pattern that repeats in the arrangement of scan electrode 2 -sustain electrode 3 -sustain electrode 3 -scan electrode 2. On the front substrate 1 of the front panel, a plurality of pairs of strip-like display electrodes 4 and black stripes (light-shielding layers) 5 made up of the scanning electrodes 2 and the sustain electrodes 3 are arranged in parallel to each other. A dielectric layer 6 serving as a capacitor is formed on the front substrate 1 so as to cover the display electrodes 4 and the light shielding layer 5, and a protective layer 7 made of magnesium oxide (MgO) is formed on the surface. Has been.

Here, the scan electrode 2 and the sustain electrode 3 are each formed by forming a bus electrode made of Ag on a transparent electrode made of a conductive metal oxide such as ITO, SnO ₂ , or ZnO.

  In the rear panel, a plurality of data electrodes 9 made of a conductive material mainly composed of parallel Ag are formed on a glass rear substrate 8, and a dielectric layer 10 is formed so as to cover the data electrodes 9. In addition, a grid-like partition wall 11 is formed thereon, and phosphor layers 12 of red, green, and blue colors are formed on the surface of the dielectric layer 10 and the side surfaces of the partition wall 11. Yes. The cross-shaped partition wall 11 is composed of a vertical partition wall 11 a formed in parallel to the data electrode 9 and a horizontal partition wall 11 b formed in a direction crossing the data electrode 9.

  The front panel and the rear panel are arranged to face each other so that the scan electrode 2 and the sustain electrode 3 and the data electrode 9 are three-dimensionally crossed, and the outer peripheral portion thereof is hermetically sealed by a sealing member made of glass frit or the like. A panel is configured by sealing discharge gas such as neon (Ne) and xenon (Xe) at a pressure of 53 kPa to 80 kPa in the discharge space 13 inside the sealed PDP. Here, a discharge cell is formed at a portion where scan electrode 2 and sustain electrode 3 and data electrode 9 face each other. In the present invention, the discharge gas sealed in the discharge space 13 is a discharge gas mixed so that the concentration of xenon is 15% or more and 30% or less in the discharge gas.

  Here, in the present invention, the dielectric layer 6 of the front panel is made of a dielectric material containing silica fine particles having a particle size of 100 nm or less, and has a film thickness of 20 μm or less and a relative dielectric constant ε of 2 or more and 4 or less. It is comprised so that.

  That is, the particles are in a dielectric material ink in which silica fine particles having a particle size of 100 nm or less, for example, a particle size of 8 nm to 20 nm and a relative dielectric constant ε of about 4, are dispersed in a siloxane polymer organic solvent, or an aqueous solution. The display electrode 4 and the light shielding layer 5 were formed using a dielectric material ink in which silica fine particles such as colloidal silica having a diameter of 100 nm or less, for example, a particle diameter of 8 nm to 20 nm and a relative dielectric constant ε of about 4, were dispersed. Thereafter, the film is applied to 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, and then dried and fired, whereby the film thickness is 20 μm or less and the relative dielectric constant ε is 2 or more and 4 or less. The dielectric layer 6 is formed.

3 (a) and 3 (b) are diagrams schematically showing the fine structure of the film of the dielectric layer 6 according to the present invention. FIG. 3 (a) shows an organic solvent containing a siloxane polymer having a particle size of FIG. 3B is a schematic diagram when the dielectric layer 6 is formed using a dielectric material ink in which silica fine particles having a relative dielectric constant ε of about 4 and a thickness of 8 nm to 20 nm are dispersed. FIG. It is a schematic diagram when the dielectric layer 6 is formed using a dielectric material ink in which silica fine particles of colloidal silica having a particle diameter of 8 nm or more and 20 nm or less and a relative dielectric constant ε of about 4 are dispersed. FIG. 3 (a), in (b), 6a silica fine particles, 6b is mesh by SiO _2, in the case of using the former dielectric ink, as shown in FIG. 3 (a), silica fine particles 6a is The microstructure is such that it is bonded and held by the network 6b made of SiO _{2. When} the latter dielectric ink is used, the microstructure is directly bonded so that the silica fine particles are aggregated.

  By the way, as in the present invention, in the front panel of the PDP, the thickness of the bus electrode portion of the display electrode 4 is about 5 μm, and the thickness of the dielectric layer 6 formed so as to cover the display electrode 4 is 20 μm. When formed thinly below, as shown in FIG. 4, the surface of the dielectric layer 6 of the front panel and the surface of the protective layer 7 formed on the dielectric layer 6 swells at the display electrode 4 portion, Unevenness is formed so as to correspond to the display electrode 4. In FIG. 4, the protective layer 7 is omitted.

  When the front panel and the rear panel having the irregularities are overlapped to form a panel, a gap is formed between the column-direction partition wall 11a formed in parallel to the data electrode 9 of the rear panel and the front panel. This will reduce the panel strength.

  Therefore, in the present invention, as shown in FIG. 4, in the partition 11 of the rear panel, the coupling for coupling the front panel to the uppermost portion of the vertical partition 11a in the column direction formed in parallel to the data electrodes 9 Layer 20 is provided. The bonding layer 20 has a yield point lower than a sealing temperature when the front panel and the rear panel are sealed by the glass frit as the sealing member, and has a characteristic that the softening point is equal to or higher than the sealing temperature. And it is comprised with the 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.

  That is, when a bonding layer 20 made of a glass material for bonding to the front panel is provided at least on the uppermost part of the vertical partition wall 11a, the front panel and the back panel are sealed with a glass frit as a sealing member. The bonding layer 20 is applied by applying a pressure uniformly over the entire surface of the front panel and the back panel, while applying a sealing temperature above the yield point and below the softening point of the glass material constituting the bonding layer 20. It is connected to the front panel. In addition, as a method of uniformly applying pressure to the front panel and the back panel over the entire surface, when sealing the front panel and the back panel with a sealing member, a gap between the front panel and the back panel is used. By reducing the pressure, it is possible to apply pressure uniformly to the front panel and the rear panel over the entire surface.

  Hereinafter, the manufacturing method of this invention is demonstrated using FIGS.

  FIG. 5 is a flowchart showing the manufacturing process of the PDP. As shown in FIG. 5, the PDP is sealed outside the image display area of the back panel created by the front panel creation process, the back panel creation process, and the back panel creation process. Applying the glass frit as the attachment member, and then pre-firing at a temperature of about 350 ° C. in order to remove the resin component of the glass frit, and the front panel and frit coating process created in the front panel creation process A sealing process for pasting and sealing the finished back panel, a subsequent exhaust process for exhausting the gas in the discharge space, and a discharge gas mainly composed of Ne and Xe inside the panel after being evacuated. The panel is completed through a discharge gas supply process.

  FIG. 6 is a diagram showing an example of a temperature profile in the sealing process, exhaust process, and discharge gas supply process used in the embodiment of the present invention. That is, in FIG. 6, a period for increasing from the room temperature to the softening point of the glass frit that is the sealing member (period 1), a period for increasing from the softening point to the sealing temperature, holding for a certain time, and then decreasing to the softening point ( Period 2) (above, sealing process), held for a certain period of time at or slightly below the softening point temperature, and then decreased to room temperature (period 3: exhaust process), discharged to the panel after decreasing to room temperature This is a period for supplying the discharge gas to the space (period 4: discharge gas supply step).

  Here, the softening point refers to a temperature at which the glass frit softens, and the softening point temperature of the glass frit in the present embodiment is about 420 ° C., for example. The sealing temperature is a temperature at which the front panel and the rear panel are sealed by the glass frit that is a sealing member, and the sealing temperature in the present embodiment is, for example, about 490 ° C. .

  FIG. 7 is a view showing a back panel according to the present invention created by the back panel creation step, and the back panel is formed on a glass back substrate 8 and has a plurality of conductive materials mainly composed of mutually parallel Ag. A data electrode 9 is formed, a dielectric layer 10 is formed so as to cover the data electrode 9, and a grid-like partition wall 11 is further formed thereon. The partition wall 11 is formed by applying a photosensitive glass material on the dielectric layer 10 and then forming it into a cross-beam shape by performing an exposure / development process and then performing a firing process. In addition, a bonding layer 20 made of a glass material containing Bi is formed on the uppermost portion of the vertical partition wall 11a of the partition wall 11.

  Here, as described above, as the glass material constituting the bonding layer 20, the yield point is not higher than the sealing temperature (for example, 490 ° C.) when sealing with the glass frit, and the softening point is determined by the glass frit. It has characteristics higher than the sealing temperature at the time of sealing. Moreover, the glass material used for the partition 11 has the characteristic that the yield point and softening point of the material become more than a sealing temperature.

  Using a back substrate having such a bonding layer 20, a glass frit as a sealing member is applied to the outside of the image display area of the back substrate, and then a temperature of about 350 ° C. is used to remove the resin component of the glass frit. After performing the frit coating process for pre-baking, by performing a sealing process in which the front substrate and the rear substrate are attached and sealed with a temperature profile as shown in FIG. 6, as shown in FIG. The bonding layer 20 is bonded to the front panel. When the front substrate and the rear substrate are sealed with glass frit as a sealing member, the softening point temperature (for example, 487 ° C.) or higher of the glass material constituting the bonding layer 20 is used. 529 ° C.) or lower sealing temperature (for example, 490 ° C.), the pressure between the front substrate and the rear substrate is reduced, and the pressure is uniformly applied over the entire surface to thereby bring the bonding layer 20 into the front surface. Bonding can be performed without causing a gap in the substrates.

Here, the sealing member is preferably a glass frit mainly composed of bismuth oxide or vanadium oxide. Examples of the glass frit containing bismuth oxide as a main component include, for example, Bi ₂ O ₃ —B ₂ O ₃ —RO—MO (where R is any one of Ba, Sr, Ca, and Mg, and M is , Cu, Sb, or 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 containing vanadium oxide as a main component, for example, a filler made of an oxide such as Al ₂ O ₃ , SiO ₂ , cordierite is added to a V ₂ O ₅ —BaO—TeO—WO glass material. Things can be used.

As the bonding layer member, a glass frit containing bismuth oxide as a composition is desirable. As the glass frit containing bismuth oxide, for example, Bi ₂ O ₃ —B ₂ O ₃ —ZnO—SiO ₂ —RO-based glass powder is used, for example, a photosensitive paste, which is applied on the partition wall 11, It can be formed into a desired shape by exposure and development. As another example, Bi ₂ O ₃ —B ₂ O ₃ —ZnO—SiO ₂ —RO glass powder is used as a paste for printing, and silk printing is performed on the partition wall 11 to form a desired shape. can do. When a glass material containing this 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 between 487 ° C. and 489 ° C. The softening point temperature is about 530 ° C.

  Next, the glass material constituting the bonding layer 20 is made of a glass material having a yield point lower than the sealing temperature when sealing with the sealing member and having a softening point higher than the sealing temperature. The reason will be explained.

  Sealing (adhesion) between glass substrates is generally performed at a temperature equal to or 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 bonding layer member in the display portion of the PDP, the glass layer as the bonding layer member is in a so-called softening flow region, and the bonding layer member flows into the cell or gas from the bonding layer. There has been a problem that the discharge voltage of the cell increases or the luminance decreases due to the increase of the emission amount.

  Therefore, as a result of studies by the present inventors, it has been found that bonding can be performed at a temperature equal to or higher than the yield point of the adhesive layer material by uniformly applying pressure over the entire surface of the front substrate and the rear substrate during bonding. It was. In a so-called sintered region that is not less than the yield point and not more than the softening point of the adhesive layer material, stable adhesion can be achieved without causing problems such as voltage increase and brightness decrease.

  According to the present invention, the front panel and the back panel are bonded by the bonding layer 20, whereby the front panel and the back panel can be brought into close contact with each other without generating a gap. Can be improved.

  Next, the adhesion area in the bonding layer 20 between the front panel and the back panel in the embodiment of the present invention will be described. FIG. 9 is a plan view seen from the front substrate 1 side showing the configuration of the image display unit of the PDP in the embodiment of the present invention. The scan electrodes 2 and the sustain electrodes 3 are alternately arranged in the column direction so as to be adjacent to each other with a discharge gap 50 in each line of the matrix display. In addition, a discharge region 51 serving as a unit light-emitting region is configured by a rectangular region that is partitioned by the barrier rib 11 and centered on a portion where the display electrode 4 and the data electrode 9 are orthogonal to each other.

  A non-discharge region 52 is formed between adjacent discharge cells, and a black stripe 5 for the purpose of improving contrast is formed in the region of the front panel. As shown in the figure, the discharge cell 51 is partitioned by the non-discharge region 52 and the central position of the barrier rib 11 with adjacent discharge cells (positions from the image display side) located on the top, bottom, left and right of the discharge cell.

  In the embodiment of the present invention, when the area of the discharge cell 51 is defined as S, the area where the front panel and the back panel are bonded in the bonding layer 20 is 10% to 30% with respect to S. It is said. In the plan view of FIG. 9, the bonded region is indicated by a bonded region 53. In the figure, the adhesion region 53 is shown only in the vicinity of the discharge cell 51, but the adhesion region also exists in other adjacent discharge cells.

  Here, R represents an adhesion area between the front panel and the rear panel in the region of the discharge cell 51. FIG. 10 shows the relationship between the adhesive strength and the drive sustaining voltage necessary for lighting with respect to the ratio R / S between the area S and the area R of the discharge cell 51.

  As shown in the figure, it can be seen that the adhesive strength between the front panel and the rear panel increases linearly according to the adhesion area. It has been confirmed that the strength of the PDP increases according to the adhesive strength.

  However, it has been found that in the region where the ratio R / S is 10% or less where the adhesion area is small, adhesion peeling occurs due to the fact that sufficient adhesion strength against vibration is not obtained in the conveyance process in the manufacturing stage. Discharge characteristics are different between a state in which the front panel and the partition walls of the rear panel are bonded to isolate each discharge cell, and a state in which there is a gap between adjacent discharge cells without bonding. That is, when partial peeling occurs in the PDP plane as described above, the voltage characteristics are different in the plane, resulting in a display defect.

  On the other hand, it has been clarified that if the adhesion area is increased too much in order to increase the adhesive strength, the sustain voltage required for driving increases rapidly from around 30%, as shown in FIG. This is thought to be due to the fact that separation between adjacent discharge cells proceeds due to an increase in the adhesion area, and sufficient exhaust cannot be performed at the time of sealing. From these facts, it is found that there is an optimum range for the bonding area, and the value is preferably between 10% and 30%.

  As described above, the present invention is a plasma display panel in which a front panel and a rear panel having partition walls that partition discharge cells are arranged to face each other and sealed around the front panel and the rear panel. Is bonded at the upper part of the barrier rib, and the bonded area is 10% or more and 30% or less with respect to the area obtained by projecting the discharge space onto the front panel or the rear panel. To do. As a result, it is possible to secure the adhesiveness necessary to suppress the occurrence of defects due to peeling or the like in the manufacturing process / market, and to suppress the increase in driving voltage, thereby realizing a high-quality PDP with high panel strength.

  As described above, the present invention is useful for realizing a plasma display device with improved panel strength.

DESCRIPTION OF SYMBOLS 1 Front substrate 2 Scan electrode 3 Sustain electrode 4 Display electrode 6 Dielectric layer 6a Silica fine particle 8 Back substrate 9 Data electrode 11 Partition 11a Vertical partition 11b Horizontal partition 12 Phosphor layer 13 Discharge space 20 Bonding layer

Claims (3)

A plasma display panel in which a front panel and a rear panel having partition walls for partitioning discharge cells are arranged to face each other, and the periphery is sealed,
The front panel and the back panel are bonded at the upper part of the partition,
The plasma display panel, wherein the bonded area is 10% or more and 30% or less with respect to an area obtained by projecting the discharge space onto a front panel or a back panel. The plasma display panel according to claim 1, wherein the barrier rib has a bonding layer, and the bonding layer contains Bi. The plasma display panel according to claim 1, wherein a yield point of a material constituting the bonding layer is equal to or higher than a sealing temperature.

Images