JP2009117154A - Plasma display panel and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a plasma display panel of high quality and high definition in which occurrence of flickering and light-out due to impact and vibration is reduced. <P>SOLUTION: In the plasma display panel, the rate of porosity of a phosphor layer is 23 to 37% or less. Thereby, even when chipping (breakage) of a partition wall occurs, scattering amount can be reduced and adhesion to the discharge electrode is reduced, and display failure such as flickering or light-out can be reduced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a phosphor of a plasma display panel (hereinafter referred to as PDP).

  Panels used in this PDP are roughly classified into AC type and DC type in terms of driving, and there are two types of discharge types: surface discharge type and counter discharge type. From the viewpoint of simplicity, at present, the mainstream of PDP is a surface discharge type with a three-electrode structure.

  In this surface discharge type PDP structure, at least a pair of substrates whose front side is transparent are arranged to face each other so that a discharge space is formed between the substrates, and a partition for partitioning the discharge space into a plurality is arranged on the substrate, In addition, a plurality of discharge cells are configured by arranging an electrode group on the substrate so that a discharge is generated in a discharge space partitioned by the partition walls, and providing phosphors that emit red, green, and blue light emitted by the discharge. The phosphors are excited by vacuum ultraviolet light having a short wavelength generated by discharge, and red, green, and blue visible light is emitted from red, green, and blue discharge cells, respectively, to perform color display.

  Such a PDP is capable of high-speed display compared to a liquid crystal panel, has a wide viewing angle, is easy to increase in size, and is self-luminous, so that the display quality is high. Recently, it has attracted particular attention among panel displays, and is used for various purposes as a display device at a place where many people gather or a display device for enjoying a large screen image at home.

In such a PDP, a circuit board constituting a drive circuit for holding a panel made mainly of glass on the front side of a chassis member made of metal such as aluminum and causing the panel to emit light on the back side of the chassis member is provided. Modules are configured by arranging them (see Patent Document 1).
JP 2003-131580 A

  By the way, in recent years, PDPs are becoming full high-definition and higher definition super high-definition. In order to increase the definition of the plasma display, it is necessary to narrow the width of the partition wall that separates the cells. However, due to the narrowing of the barrier ribs, chipping (chips) are likely to occur in part of the barrier ribs due to impact and vibration on the panel, and the phosphor powder disposed on the barrier ribs is scattered and adheres to the discharge electrode. There is. As a result, there is a problem that the discharge start voltage of the cell to which the phosphor is adhered rises and the discharge is not started at the set voltage, causing display defects such as flickering and non-lighting and lowering the image quality.

  The present invention has been made in view of such a current situation, and by configuring the porosity of the phosphor disposed on the back plate partition wall within a certain range, the amount of scattering can be reduced even when the partition wall chipping occurs. Can be reduced. As a result, adhesion on the discharge electrode is reduced, and an object is to reduce display defects such as flickering and non-lighting.

  In order to solve this problem, the PDP of the present invention is characterized in that the porosity of the phosphor layer is 23% or more and 37% or less. In addition, the method for producing a PDP of the present invention includes a step of heating only the substrate side on which the phosphor layer is disposed to dry the phosphor layer. In this case, the phosphor layer may be dried by heating the substrate to 80 ° C. or more and 200 ° C. or less.

  According to the present invention, it is possible to obtain a high-definition and high-definition PDP in which the occurrence of flickering and non-lighting due to impact or vibration is reduced.

  Hereinafter, although PDP by one Embodiment of this invention is demonstrated using FIGS. 1-3, the aspect of this invention is not limited to this.

  First, the structure of the panel in the PDP will be described with reference to FIG. As shown in FIG. 1, the panel is configured by disposing a glass front substrate 1 and a back substrate 2 so as to form a discharge space therebetween. On the front substrate 1, a plurality of scanning electrodes 3 and sustaining electrodes 4 constituting display electrodes are formed in parallel with each other. A dielectric layer 5 is formed so as to cover the scan electrode 3 and the sustain electrode 4, and a protective layer 6 is formed on the dielectric layer 5.

  A plurality of data electrodes 8 covered with an insulator layer 7 are provided on the back substrate 2, and a grid-like partition wall 9 is provided on the insulator layer 7. A phosphor layer 10 is provided on the surface of the insulator layer 7 and on the side surfaces of the partition walls 9. The front substrate 1 and the rear substrate 2 are arranged to face each other so that the scan electrodes 3 and the sustain electrodes 4 and the data electrodes 8 cross each other, and in the discharge space formed between them, for example, neon And a mixed gas of xenon. Note that the structure of the panel is not limited to the above-described structure, and for example, a structure having a stripe-shaped partition may be used.

  An example of a method for manufacturing the above PDP will be described below. First, a photosensitive paste for electrode formation is formed on the front substrate 1 by a screen printing method or the like. Thereafter, patterning of the display electrode is performed by performing exposure and development. After forming the pattern of the display electrode, the dielectric layer 5 is formed and baked by using a screen printing method or a coating method so as to cover it. Further, a protective layer 6 such as MgO is formed thereon by vapor deposition.

  A photosensitive paste for the data electrode 8 is formed on the back substrate 2 by a screen printing method, and then the pattern of the data electrode 8 is formed by exposure and development. Then, a dielectric layer 7 is formed on the data electrode 8 by screen printing or coating, and a photosensitive paste is applied in several steps to form a grid-like or striped barrier rib 9 thereon. It is formed by the method and exposed. At this time, it is possible to form a structure having at least two steps depending on the number of times the paste is applied and the exposure pattern. After pattern formation by development, baking is performed. After firing, the RGB phosphor layer 10 is disposed inside the partition wall 9 by a dispenser method or the like, and is dried in a high temperature atmosphere.

  The front substrate 1 and the rear substrate 2 produced by the above method are arranged so that the film surfaces face each other, and sealing is performed. At this time, sealing is performed with frit glass or the like disposed around the back substrate.

  Thereafter, the substrate is evacuated while being heated through the exhaust holes arranged on the back substrate 2 side, and after reaching a certain degree of vacuum, a rare gas such as xenon or neon is sealed inside the panel. After gas filling, the exhaust pipe is sealed to complete the panel.

  Next, the characteristic part of the PDP according to the present embodiment will be described in detail.

  Usually, the porosity of the phosphor layer 10 disposed on the partition wall varies depending on the phosphor and the color. In the PDP according to the embodiment of the present invention, control is performed by optimizing the paste used as a precursor and the drying process so that the porosity of the phosphor layer 10 disposed in the partition wall is 23% or more and 37% or less. It is characterized by arranging.

  Here, the porosity is a value measured by the following porosity measurement method. First, a sample to be measured is prepared. In the present embodiment, a part of the back substrate 2 provided with the phosphor layer 10 and the like is cut out and embedded with an epoxy resin or the like. Thereafter, the cross section is formed by polishing or the like so that the cross sectional structure of the back substrate 2 can be observed.

  Then, the cross-section is observed using a microscope observation device such as an SEM, and an image is taken in a state in which the resin portion and the phosphor portion are contrasted. From the image, the area ratio between the portion where the phosphor layer 10 is disposed and the portion where the above-described epoxy resin is present is calculated by image processing software. The area ratio of the gap part (part filled with resin) obtained by this is defined as the void ratio. Here, FIG. 2 shows a schematic diagram of an observation image of the phosphor layer (in FIG. 2, the black part is the phosphor particle and the white part is the gap part). For the calculation, for example, an arbitrary region (a portion indicated by an area a × b in the figure) is determined, and a determination is made based on the existence ratio in the region.

  As a result of various studies, the inventors have found that there is a relationship between the porosity and the occurrence rate of display defects such as non-lighting caused by the phosphor. The result is shown in FIG. Here, the display defect occurrence ratio is calculated from the number of display defects generated in a certain number of productions. As can be seen from this figure, as the porosity of the phosphor layer 10 increases, the display defect occurrence ratio, that is, the non-light generation ratio increases.

  In addition, the display defect occurrence rate needs to be 0.3 or less from the relationship with the number of yields in mass production of PDPs. That is, from the relationship of FIG. 3, the porosity of the phosphor layer 10 needs to be 37% or less.

  This is because the distance between the phosphor particles decreases and the intermolecular force increases by controlling the porosity of the phosphor layer at 37% or less, and the phosphor is affected by impacts and chipping of the partition walls. It is considered that the layer 10 can be prevented from scattering on the discharge electrode.

  On the other hand, the porosity of the phosphor layer 10 needs to be 23% or more. This is because the phosphor layer 10 is made fine as a result of the experiment, and the material and the drying temperature during production are stably maintained.

  Next, the method for forming the phosphor layer in the embodiment of the present invention will be described in detail. As a method for forming the phosphor, first, a phosphor paste is injected into the partition wall by a dispenser or an ink jet method.

  Here, in the prior art, as a method for drying the phosphor paste injected into the partition walls, a high temperature atmosphere drying method is used that maintains the temperature at about 80 to 150 ° C. using IR or the like.

  However, in this method, drying is performed by volatilizing the solvent in the paste from the paste surface, so that the phosphor volume after drying becomes large, and the porosity of the phosphor layer 10 becomes large after the subsequent firing step. There is a tendency to end up. In particular, it is difficult to maintain the porosity of the phosphor layer 10 at 37% or less.

  On the other hand, as a method for drying the phosphor layer 10 in the embodiment of the present invention, the phosphor injected into the partition walls is heated from the back side of the substrate by a hot plate or the like. The surface temperature of the hot plate at this time is preferably in the range of 80 to 250 ° C. This is because when the temperature is 80 ° C. or lower, the drying speed is extremely decreased, and when the temperature is 250 ° C. or higher, the resin after drying is deteriorated.

  Moreover, it is desirable that the appropriate temperature increase rate range of the substrate at this time is 0.3 ° C. to 5 ° C./second. By setting it within this range, the effect of the embodiment of the present invention can be easily obtained. Furthermore, at this time, the time required for drying can be shortened by blowing dry air from the substrate surface.

  By using such a drying method, the phosphor shrink rate during drying can be increased, and the phosphor porosity after firing can be reduced to 37% or less.

  Note that the difference from the phenomenon of the prior art high temperature atmosphere drying is that in the embodiment of the present invention, drying from the partition wall side is started by heating from the back surface, so that the solvent volatilization of the phosphor paste is promoted, This is considered to be caused by the phosphor volume (film thickness) being thinner (smaller) than that in high-temperature atmosphere drying.

  Furthermore, this hot plate drying can raise only the temperature of the substrate, and there is no need to raise the temperature in the entire furnace as in the conventional high-temperature atmosphere drying, thereby reducing the power and equipment costs during production. There are also advantages.

  In the embodiment of the present invention, if only the phosphor layer 10 disposed on the side surface of the partition wall 9 among the phosphor layers 10 disposed on the back substrate 2 is 37% or less in porosity, the present invention is carried out. The effect of the form is obtained. This is based on the following reason.

  Display defects (non-lighting, flickering) caused by impact or deflection on the panel are caused by chipping of the barrier ribs 9, and only the phosphor layer 10 disposed on the side surface of the barrier ribs 9 is scattered and adheres to the discharge electrode. However, it is generated by increasing the discharge start voltage at that point. Therefore, the discharge electrode of the phosphor layer 10 is prevented from being scattered by the chipping of the barrier rib 9, that is, only the side surface of the barrier rib 9 has a phosphor porosity of 37% or less. Splashing upward can be suppressed.

  In the present invention, the effect becomes more prominent as the phosphor particles become smaller. Specifically, a phosphor layer having an average particle diameter of 3.3 μm ± 0.5 μm can reduce the display defect rate compared to a phosphor layer having an average particle diameter of 3.7 μm ± 0.5 μm. It was.

  As described above, in the present invention, by controlling and arranging the porosity of the phosphor layer 10, flickering and non-lighting due to impact or vibration can be suppressed, and a high-definition and high-definition PDP can be provided.

  As described above, the present invention is useful for providing a large-screen, high-definition PDP.

The perspective view which shows the principal part of the plasma display panel by embodiment of this invention Schematic showing the cross section of the phosphor layer of the plasma display panel Explanatory drawing which shows the relationship between the porosity of the fluorescent substance layer of the plasma display panel, and the display defect occurrence rate

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front substrate 2 Back substrate 3 Scan electrode 4 Sustain electrode 5 Dielectric layer 6 Protective layer 7 Insulator layer 8 Data electrode 9 Partition 10 Phosphor layer

Claims (3)

A plasma display panel having a porosity of a phosphor layer of 23% or more and 37% or less. A method of manufacturing a plasma display panel in which a phosphor layer is disposed on at least one substrate, comprising a step of heating only the substrate side on which the phosphor layer is disposed to dry the phosphor layer. A method for manufacturing a plasma display panel. A method of manufacturing a plasma display panel, wherein the phosphor layer is dried by heating the substrate to 80 ° C. or more and 200 ° C. or less.