JP2005135831A - Plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the coloring of a dielectric layer in a plasma display panel. <P>SOLUTION: This plasma display panel includes a front plate 1 in which a plurality of indication electrodes 6 are arranged so that flat discharge gaps are formed therebetween, and a dielectric layer 8 is formed so as to cover the indication electrodes 6; and a rear plate 2 which is arranged so as to be opposed to the front plate 1 forming discharge space between two plates, and in which a plurality of address electrodes 11 are arranged so as to form discharge cells with the indication electrodes 6. An electrode of the front plate is composed by adding at least one material selected from Pt, Rh, Pd, Ru, Ir or their oxides or composite oxides containing them, Co<SB>3</SB>O<SB>4</SB>, MnO<SB>2</SB>, and CrO<SB>2</SB>. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a plasma display panel used for a display device or the like.

  As a display device for displaying high-definition television images on a large screen, there is an increasing expectation for a device using a plasma display panel (hereinafter referred to as PDP).

  A PDP basically includes a front plate and a back plate. The front plate is a glass substrate, a display electrode made of a striped transparent electrode and a bus electrode formed on one main surface thereof, a dielectric glass layer that covers the display electrode and functions as a capacitor, It is comprised with the protective layer which consists of MgO formed on this dielectric material layer. As a glass substrate, an Ag material is used to form a transparent electrode by a thin film process and to ensure conductivity on a glass substrate by a float method suitable for manufacturing a glass having an easily flat area and excellent flatness. A bus electrode is formed by baking a paste containing a predetermined pattern and then firing. Furthermore, in order to improve contrast, a light shielding layer is formed between display electrodes, a dielectric layer is formed by applying and baking a dielectric paste so as to cover the whole, and finally a protective layer made of MgO is widened. It is formed using a known post-operative technique for thin film formation.

  On the other hand, the back plate is composed of a glass substrate, a stripe-shaped address electrode formed on one main surface of the glass substrate, a dielectric layer covering the address electrode, a partition formed thereon, and between each partition. The formed phosphor layer emits red, green and blue light respectively.

  The front plate and the back plate are hermetically sealed with their electrode forming surfaces facing each other, and a discharge gas such as Ne—Xe is sealed at a pressure of 400 Torr to 600 Torr in the discharge space formed by the barrier ribs.

  This PDP discharges by selectively applying a video signal voltage to the display electrodes, and the ultraviolet rays generated thereby excite each color phosphor layer to emit red, green, and blue light, and display a color image. Realized.

In the PDP having such a configuration, the display electrode includes a transparent electrode, a black layer (black electrode) for suppressing external light reflection, and a low-resistance conductive layer (metal electrode) mainly composed of metal. However, as disclosed in, for example, Patent Document 1, the display electrode group is composed of a plurality of layers formed on the surface-side substrate, and one of the plurality of layers is black with higher sheet resistance than the other layers. It has been proposed that the material utilization rate is improved and the man-hours are reduced by forming the light shielding portion with the black layer of the display electrode group.
JP 2002-83547 A

  An object of the present invention is to reduce coloring of a dielectric layer in such a PDP.

In order to achieve this object, the present invention provides a front plate in which a plurality of electrodes are arranged so as to form a surface discharge gap therebetween, and a dielectric layer is formed so as to cover the electrodes. A back plate formed by arranging a plurality of address electrodes so as to form a discharge cell with the electrodes, and opposingly arranged so that a discharge space is formed between the face plates, and the electrodes of the front plate are , Pt, Rh, Pd, Ru, Ir, oxides thereof or composite oxides containing them, Co ₃ O ₄ , MnO ₂ , CrO ₂ are added and configured. And

In the present invention, a plurality of electrodes are arranged and formed so that a surface discharge gap is formed therebetween, and a light shielding layer is formed between the electrodes where the surface discharge gap is not formed, and the electrodes and the light shielding layer are covered. A plurality of address electrodes are arranged so as to form a discharge cell with the front plate having a dielectric layer formed thereon and the front plate so that a discharge space is formed between the front plate and the electrode. The electrode of the front plate is composed of a plurality of conductive layers including a black layer made of the same material as the light shielding layer, and the electrode includes Pt, Rh, Pd, Ru, Ir or It is characterized in that at least one material selected from those oxides or composite oxides containing them, Co ₃ O ₄ , MnO ₂ and CrO ₂ is added.

  In the present invention, the electrodes on the front plate are made of a conductive material containing Ag.

  As described above, according to the present invention, even in the case of an electrode using a silver material having excellent conductivity, it is possible to reduce the coloring of the dielectric layer made of a glass material, and it is possible to reduce the luminance without deteriorating the luminance. A plasma display panel can be provided.

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

  FIG. 1 is a cross-sectional perspective view showing a main part of a main configuration of a PDP according to an embodiment of the present invention. In the figure, the z direction corresponds to the thickness direction of the PDP, and the xy plane corresponds to a plane parallel to the PDP surface. 2 is a cross-sectional view taken along line AA in FIG.

  As shown in FIG. 1, the PDP includes a front plate 1 and a back plate 2 that are arranged to face each other so that a discharge space is formed.

  First, in the front plate 1, a plurality of striped transparent electrodes 4 are formed in parallel on the surface of the front glass substrate 3 on the back plate 2 side with the x direction as the longitudinal direction. Further, as shown in FIG. 2, bus electrodes 5 that are narrower than the transparent electrodes 4 and excellent in conductivity are disposed on the transparent electrodes 4 along the edges of the transparent electrodes 4. Is configured. The plurality of display electrodes 6 are formed so as to form a surface discharge gap therebetween, and between the electrodes on which the surface discharge gap is not formed, that is, on the edge side where the bus electrode 5 is formed, A light shielding layer 7 is provided to shield white from the phosphor layer when no light is emitted and to improve contrast.

The bus electrode 5 is composed of a black layer 5a and a conductive layer 5b made of a conductive material containing Ag formed on the black layer 5a. As a result, the electrodes of the front plate 1 are transparent electrodes 4 and bus electrodes. 5 black layers 5a and conductive layers 5b. Note that the black layer 5a may be not only black black but also blackish color such as gray. In addition, the conductive layer 5b of the bus electrode 5 is made of platinum group such as Pt, Rh, Pd, Ru, Ir, oxides thereof or composite oxides containing them, Co ₃ O ₄ , MnO ₂ , CrO _2, etc. It is composed of at least one material selected from the inside added with about 0.5 wt% to 5 wt%.

Here, the black layer 5a is made of the same material as the light-shielding layer 7 and has a material configuration including a black pigment not including Cu as a constituent component, that is, a configuration including at least a black pigment not including Cu as a constituent component and a conductive material. is there. As the black pigment used for the black layer 5a and the light shielding layer 7, at least one selected from Ni—Mn—Fe—Co, Co—Cr—Ni, and Co ₃ O ₄ can be used. The fact that Cu is not a constituent component does not mean that Cu is not contained at all, but Cu may be contained as long as it is contained to the extent of impurities, for example, 1% or less.

Then, a dielectric made of a dielectric glass material is provided on the front glass substrate 3 on which the display electrode 6 composed of the transparent electrode 4 and the bus electrode 5 and the light shielding layer 7 are formed so as to cover the display electrode 6 and the light shielding layer 7. A layer 8 is formed, and a protective film 9 is laminated over the entire area of the dielectric layer 8. Here, the dielectric layer 8 is applied with a paste containing dielectric glass powder (PbO, SiO ₂ , B ₂ O ₃ , Al ₂ O _3, etc.) containing titanium oxide (TiO ₂ ) and fired. It is formed by.

  In the back plate 2, a plurality of address electrodes 11 are arranged in parallel on the surface of the back glass substrate 10 on the front plate 1 side so as to form discharge cells with the display electrodes 6 in a stripe shape with the y direction as the longitudinal direction. Further, a dielectric layer 12 is formed so as to cover the address electrode 11. On the dielectric layer 13, a stripe-shaped partition wall 13 is disposed so as to be positioned on a region between the address electrodes 11. Phosphor layers 14 that emit light in red, green, and blue are regularly arranged and formed in stripe-shaped recesses formed by the barrier ribs 13 and the dielectric layers 12.

  As shown in FIG. 1, the front plate 1 and the back plate 2 having such a configuration are disposed so that the address electrodes 12 and the display electrodes 6 are substantially orthogonal to each other. The discharge space surrounded by the stripe-shaped recess formed of the dielectric layer 12 and the protective film 9 of the front plate 1 is filled with a discharge gas, and the outer peripheral edge portions of the front plate 1 and the back plate 2 are sealed. Sealed with glass. Here, as shown in FIG. 2, a region where a pair of adjacent display electrodes 6 and one address electrode 11 cross each other is a discharge cell related to image display. The discharge space 15 is filled with a discharge gas (filled gas) made of a rare gas component such as He, Xe, or Ne at a pressure of about 400 Torr to 600 Torr.

  In this PDP, short-wave ultraviolet rays (wavelength of about 147 nm) are generated by discharge generated in each discharge cell, and the phosphor layer 14 is excited to emit light by the ultraviolet rays, so that an image can be displayed.

  Next, a specific method for manufacturing the front plate 1 in the present embodiment will be described. FIG. 3 is a diagram schematically showing an example of the manufacturing process of the front plate in the PDP according to the embodiment of the present invention.

In FIG. 3, FIG. 3A shows that a transparent electrode material film 16 made of ITO, tin oxide (SnO ² ), or the like is uniformly formed on the front glass substrate 3 formed by the float method by a sputtering method or the like. In this step, the transparent electrode material film 16 is patterned into a desired shape using a photolithography method, thereby forming the transparent electrode 4 as shown in FIG.

  At this time, a positive resist mainly composed of a novolak resin is applied in a film thickness of 1.5 μm to 2 μm, and ultraviolet rays are exposed through an exposure dry plate having a desired pattern to cure the resist. Next, development is performed with an alkaline aqueous solution to form a resist pattern. Thereafter, the substrate is immersed in a solution containing hydrochloric acid as a main component, etching is performed, unnecessary portions are removed, and finally the resist is removed, followed by a drying process, whereby the patterned transparent electrode 4 is obtained. It is formed.

Next, as shown in FIG. 3C, the black layer 5 a and the light shielding layer 7 of the bus electrode 5 are formed on the transparent electrode 4 and between the transparent electrodes 4. Materials used in this step are black pigments, conductive materials, glass frit (PbO—B ₂ O ₃ —SiO ₂ type, Bi ₂ O ₃ —B ₂ O ₃ —SiO ₂ type, etc.), organic solvents, and the like as components. It is a photosensitive paste containing. Here, as described above, the black pigment is at least one selected from Ni—Mn—Fe—Co, Co—Cr—Ni, Co—Cr—Fe, and Co ₃ O ₄ not containing Cu as a constituent component. Is used as a main component.

  As a forming method, after forming a film made of the above-mentioned material by a screen printing method, a sheet method, or the like, exposure is performed by irradiating ultraviolet rays through an exposure dry plate having a desired pattern, and then development is performed using an alkaline developer. Thus, the black layer 5a and the light shielding layer 7 having a predetermined pattern can be formed.

Next, as shown in FIG. 3D, a conductive layer 5 b made of the above-described conductive material containing Ag is formed on the black layer 5 a of the bus electrode 5. Materials used in this step are conductive materials containing silver (Ag), glass frit (PbO—B ₂ O ₃ —SiO ₂ system, Bi ₂ O ₃ —B ₂ O ₃ —SiO ₂ system, etc.), organic A photosensitive paste containing a solvent or the like as a component. As a formation method, similarly to the formation method of the black layer 5a and the light shielding layer 7, a film made of the above material is formed by a screen printing method, a sheet method, or the like, and then irradiated with ultraviolet rays through an exposure dry plate having a desired pattern. The conductive layer 5b having a predetermined pattern can be formed by exposing to light and then developing using an alkaline developer.

  Then, after drying the black layer 5a and the conductive layer 5b and the light shielding layer 7 having a predetermined pattern shape, firing is performed at a temperature equal to or higher than the softening point of the glass material, so that the front glass substrate 3 and the transparent electrode are baked. The light shielding layer 7 and the bus electrode 5 can be formed on 4.

  Thereafter, the dielectric layer 8 and the protective film 9 are formed. As shown in FIG. 3 (e), the dielectric layer 9 is formed by using a screen printing method or the like with a paste containing dielectric glass powder. After applying to the entire surface of the display area and then removing the solvent contained in the paste by a drying process using a drying furnace, the dielectric layer 8 is formed by baking at a temperature of about 600 ° C. At this time, the film thickness of the dielectric layer 8 is about 30 μm.

  Further, as shown in FIG. 3F, the protective film 9 is formed by depositing about 600 nm of MgO on the dielectric layer 8 by the electron beam evaporation method. Complete. By attaching the front plate 1 and the back plate 2 together, a PDP is completed.

Here, in the present invention, the bus electrode 5 is made of platinum group such as Pt, Rh, Pd, Ru, Ir or oxides thereof or composite oxides containing them, such as Co ₃ O ₄ , MnO ₂ , CrO ₂ . At least one material selected from among them is added, and coloring of the dielectric layer made of a glass material can be reduced. The reason for this will be described below.

Coloring of the dielectric layer (yellowing) is in the firing step, separated from the silver ions (Ag ⁺⁾ as an electrode when the silver compound in the bus electrodes using Ag is decomposed, the silver ions (Ag ⁺⁾ Glass Although it is known that it occurs by diffusing into a dielectric layer made of a material, the present inventors have reported that the bus electrode 5 is made of Pt, Rh, Pd, Ru, Ir, or an oxide thereof or a composite containing them. It has been found that there is a difference in coloring of the dielectric layer made of a glass material by adding at least one material selected from platinum group such as oxide, Co ₃ O ₄ , MnO ₂ , CrO _{2 and the} like. .

Then, as a result of examining the coloring phenomenon of the dielectric layer, the bus electrode 5 has a platinum group such as Pt, Rh, Pd, Ru, Ir, or an oxide thereof or a composite oxide containing them, Co ₃ O _4. In the case where at least one material selected from MnO ₂ , CrO _{2 and the} like is not added, the dielectric layer is colored yellow, and the dielectric layer further contains titanium oxide (TiO ₂ ). In the case where it is made of a glass material, it is colored red, whereas the bus electrode 5 is made of a platinum group such as Pt, Rh, Pd, Ru, Ir or an oxide thereof or a complex oxide containing them, Co ₃ When at least one material selected from O ₄ , MnO ₂ , CrO ₂ or the like is added, the dielectric layer is colored yellow or red regardless of the dielectric glass material of the dielectric layer. Was found to be reduced. This is because the material selected from the platinum group such as Pt, Rh, Pd, Ru, Ir or oxides thereof or composite oxides containing them, Co ₃ O ₄ , MnO ₂ , CrO _2, etc. It is presumed that the diffusion into the dielectric layer is suppressed, or the reaction in which silver ions are reduced to silver (colloid) is suppressed.

  In addition, if the addition amount of these materials is about 0.5 wt%-5 wt%, the effect of this invention of reducing coloring can be acquired.

  As described above, according to the present invention, it is a useful invention for providing a high quality PDP by preventing a decrease in luminance of the PDP.

The perspective view which shows the main structures of the plasma display panel by one embodiment of this invention Sectional drawing cut | disconnected by the AA line of FIG. Sectional drawing which shows an example of the process of manufacturing the front plate of the plasma display panel of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front plate 2 Back plate 3 Front glass substrate 4 Transparent electrode 5 Bus electrode 6 Display electrode 7 Light shielding layer 8 Dielectric layer 9 Protective film 10 Back glass substrate 11 Address electrode 12 Dielectric layer 13 Phosphor layer 14 Partition 15 Discharge space

Claims (3)

A front plate in which a plurality of electrodes are arranged so that a surface discharge gap is formed and a dielectric layer is formed so as to cover the electrodes, and a discharge space is formed between the front plates. And a back plate formed by arranging a plurality of address electrodes so as to form a discharge cell with the electrodes, and the electrodes of the front plate are Pt, Rh, Pd, Ru, Ir or A plasma display panel comprising at least one material selected from those oxides or composite oxides containing them, Co ₃ O ₄ , MnO ₂ , and CrO ₂ . A plurality of electrodes are formed so as to form a surface discharge gap therebetween, and a light shielding layer is formed between the electrodes where the surface discharge gap is not formed, and a dielectric layer is formed so as to cover the electrode and the light shielding layer. A front plate formed, and a back plate formed by arranging a plurality of address electrodes so as to form a discharge cell with the electrodes, and facing each other so that a discharge space is formed between the front plates. The electrode of the front plate is composed of a plurality of conductive layers including a black layer made of the same material as the light shielding layer, and the electrode includes Pt, Rh, Pd, Ru, Ir, oxides thereof, or A plasma display panel, wherein at least one material selected from a complex oxide containing Co, O ₃ O ₄ , MnO ₂ and CrO ₂ is added. The plasma display panel according to claim 1 or 2, wherein an electrode of the front plate is made of a conductive material containing Ag.

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