JP2008269862A - Plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma display panel having good image display contrast and giving consideration to environmental problems. <P>SOLUTION: In this PDP, a front plate in which a display electrode, a shielding layer, and a dielectric layer are formed on a glass substrate, and a back plate in which an electrode, a barrier plate, and a phosphor layer are formed on a substrate are disposed face to face and their peripheries are sealed to form a discharge space. The display electrode is formed by a plurality of layers including at least a metal electrode layer containing silver and a glass material, the content of bismuth oxide (Bi<SB>2</SB>O<SB>3</SB>) in the dielectric layer is not less than 5 wt.% and not more than 25 wt.%, and the content of glass bismuth oxide (Bi<SB>2</SB>O<SB>3</SB>) of the glass material in the metal electrode layer is not less than 5 wt.% and not more than 25 wt.%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  A plasma display panel (hereinafter referred to as a PDP) can realize high definition and a large screen, and therefore, a television of 100 inches or more class has been commercialized. In recent years, PDP has been applied to full high-definition whose number of scanning lines is more than twice that of the conventional NTSC system, and PDP which does not contain a lead component is required in consideration of environmental problems. In addition, in order to save resources and reduce material costs, it is necessary to reduce expensive rare metals.

  A PDP basically includes a front plate and a back plate. The front plate covers a display electrode composed of a glass substrate of sodium borosilicate glass by a float method, a striped transparent electrode and a bus electrode formed on one main surface of the glass substrate, and the display electrode. The dielectric layer functions as a capacitor, and a protective layer made of magnesium oxide (MgO) formed on the dielectric layer. On the other hand, the back plate is a glass substrate, stripe-shaped address electrodes formed on one main surface thereof, a base dielectric layer covering the address 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 plate and the back plate are hermetically sealed with their electrode forming surfaces facing each other, and Ne—Xe discharge gas is sealed at a pressure of 400 Torr to 600 Torr in a discharge space partitioned by a partition wall. PDP discharges by selectively applying a video signal voltage to the display electrode, and the ultraviolet rays generated by the discharge excite each color phosphor layer to emit red, green and blue light, thereby realizing color image display is doing.

  Silver electrodes for ensuring conductivity are used for the bus electrodes of the display electrodes, and low-melting glass mainly composed of lead oxide is used for the dielectric layer. However, due to recent environmental concerns Examples in which a lead component is not included as a dielectric layer are disclosed (see, for example, Patent Documents 1, 2, 3, and 4).

In addition, an example in which a predetermined amount of bismuth oxide (Bi ₂ O ₃ ) is contained as a glass material for forming an electrode is also disclosed (for example, see Patent Document 5).
JP 2003-128430 A JP 2002-053342 A JP 2001-045877 A JP-A-9-050769 JP 2000-0486645 A

  In recent years, PDP has been applied to full high-definition whose number of scanning lines is more than twice that of the conventional NTSC system, and at the same time, higher brightness and improved contrast are being achieved.

  However, in the case of using a dielectric layer that does not contain a lead component or a glass material of an electrode, which is used for consideration of environmental problems, the black luminance caused by the black layer or the light shielding layer of the display electrode is deteriorated. However, there is a problem that the contrast is lowered and good image quality cannot be ensured.

  In addition, there is a need to reduce expensive rare metals due to resource savings and soaring materials, but depending on the selection of the black material component of the black layer and the light shielding layer, the metal electrode that serves as the display electrode's bus bar to the transparent electrode There has been a problem that image quality is affected by an increase in resistance value in the vertical direction of the substrate (hereinafter referred to as a contact resistance value) and an increase in power consumption.

  An object of the present invention is to solve such problems and to realize a PDP that ensures good image quality even in high-definition display and further considers environmental issues.

In order to solve the above problems, the PDP of the present invention comprises a front plate having a display electrode and a dielectric layer formed on a glass substrate, and a back plate having electrodes, barrier ribs, and a phosphor layer formed on the substrate. A PDP having a discharge space formed by facing and sealing the periphery, wherein the display electrode is composed of a plurality of layers including a metal electrode layer containing at least silver and a glass material, and oxidation of the dielectric layer The content of bismuth (Bi ₂ O ₃ ) is 5 wt% or more and 25 wt% or less, and the content of bismuth oxide (Bi ₂ O ₃ ) in the glass material of the metal electrode layer is 5 wt% or more and 25 wt%. % Or less. The black layer contains cobalt (Co), nickel (Ni), copper (Cu), or an oxide thereof.

  According to the configuration of the present invention as described above, it is possible to provide a PDP having good image display quality and considering environmental problems.

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

(Embodiment)
FIG. 1 is a perspective view showing the structure of a PDP according to an embodiment of the present invention. The basic structure of the PDP is the same as that of a general AC surface discharge type PDP. As shown in FIG. 1, the PDP 1 has a front plate 2 made of a front glass substrate 3 and a back plate 10 made of a back glass substrate 11 facing each other, and its outer peripheral portion is sealed with a glass frit or the like. The material is hermetically sealed. The discharge space 16 inside the sealed PDP 1 is filled with a discharge gas such as Ne or Xe at a pressure of 400 Torr to 600 Torr.

  On the front glass substrate 3 of the front plate 2, a pair of strip-shaped display electrodes 6 each composed of the scanning electrodes 4 and the sustain electrodes 5 and the light shielding layers 7 are arranged in a plurality of rows in parallel with each other. A dielectric layer 8 serving as a capacitor is formed on the front glass substrate 3 so as to cover the display electrode 6 and the light shielding layer 7, and a protective layer 9 made of magnesium oxide (MgO) is formed on the surface. Has been.

  On the back glass substrate 11 of the back plate 10, a plurality of strip-like address electrodes 12 are arranged in parallel to each other in a direction perpendicular to the scanning electrodes 4 and the sustain electrodes 5 of the front plate 2. Layer 13 is covering. Further, a partition wall 14 having a predetermined height is formed on the base dielectric layer 13 between the address electrodes 12 to divide the discharge space 16. For each address electrode 12, a phosphor layer 15 that emits red, blue, and green light by ultraviolet rays is sequentially applied to the grooves between the barrier ribs 14 and formed. A discharge cell is formed at a position where the scan electrode 4 and the sustain electrode 5 intersect with the address electrode 12, and the discharge cell having red, blue and green phosphor layers 15 arranged in the direction of the display electrode 6 is used for color display. Become a pixel.

FIG. 2 is a cross-sectional view showing the configuration of the front plate 2 of the PDP in the embodiment of the present invention. 2 is shown upside down from FIG. As shown in FIG. 2, a display electrode 6 and a light shielding layer 7 including scanning electrodes 4 and sustain electrodes 5 are formed in a pattern on a front glass substrate 3 manufactured by a float method or the like. Scan electrode 4 and sustain electrode 5 are each composed of transparent electrodes 4a and 5a made of indium oxide (ITO), tin oxide (SnO ₂ ), and the like, and metal bus electrodes 4b and 5b formed on transparent electrodes 4a and 5a. Has been. The metal bus electrodes 4b and 5b are used for the purpose of imparting conductivity in the longitudinal direction of the transparent electrodes 4a and 5a, and are formed of a conductive material whose main component is a silver (Ag) material. Furthermore, the metal bus electrodes 4b and 5b are composed of black black electrodes 41b and 51b and white white electrodes 42b and 52b.

  The dielectric layer 8 includes a first dielectric layer 81 provided on the front glass substrate 3 so as to cover the transparent electrodes 4a and 5a, the metal bus electrodes 4b and 5b, and the light shielding layer 7, and a first dielectric. The second dielectric layer 82 formed on the layer 81 has at least two layers, and the protective layer 9 is formed on the second dielectric layer 82.

  Next, a method for manufacturing a PDP will be described. First, the scan electrode 4, the sustain electrode 5, and the light shielding layer 7 are formed on the front glass substrate 3. The transparent electrodes 4a and 5a and the metal bus electrodes 4b and 5b are formed by patterning using a photolithography method or the like. The transparent electrodes 4a and 5a are formed using a thin film process or the like, and the metal bus electrodes 4b and 5b are solidified by baking a paste containing conductive black particles or silver (Ag) material at a desired temperature. Similarly, the light shielding layer 7 is also formed by screen printing a paste containing a black material or by forming a black material on the entire surface of the glass substrate, patterning it using a photolithography method, and baking it.

  A specific procedure for forming the metal bus electrodes 4b and 5b is generally the following procedure. A paste containing a black material is printed on the front glass substrate 3 and dried, followed by patterning by a photolithography method to form the light shielding layer 7. Further, a paste containing a pigment and a paste containing conductive particles are printed and dried repeatedly. Thereafter, patterning is performed by photolithography to form metal bus electrodes 4b and 5b composed of black black electrodes 41b and 51b and white white electrodes 42b and 52b. Here, in order to improve the contrast during image display, the black electrodes 41b and 51b are formed in the lower layer (front glass substrate 3 side), and the white electrodes 42b and 52b are formed as the upper layer.

  In the embodiment of the present invention, the black electrodes 41b and 51b of the metal bus electrode and the light shielding layer 7 are made of the same material, and a procedure of manufacturing in the same process is used. Since the present invention is a technique for improving the blackness, in the embodiment of the present invention, the blackness of the light shielding layer 7 is also improved, and the effect of the present invention can be enhanced.

  Next, a dielectric paste is applied on the front glass substrate 3 by a die coating method or the like so as to cover the scan electrode 4, the sustain electrode 5, and the light shielding layer 7, thereby forming a dielectric paste layer (dielectric glass layer). After the dielectric paste is applied, the surface of the applied dielectric paste is leveled by leaving it to stand for a predetermined time, so that a flat surface is obtained. Thereafter, the dielectric paste layer is baked and solidified to form the dielectric layer 8 that covers the scan electrode 4, the sustain electrode 5, and the light shielding layer 7. In the embodiment of the present invention, the dielectric layer 8 having a two-layer structure including the first dielectric layer 81 and the second dielectric layer 82 is formed by repeating at least the coating process of the dielectric paste. ing. The dielectric paste is a paint containing powdery dielectric glass, a binder, and a solvent. Next, a protective layer 9 made of magnesium oxide (MgO) is formed on the dielectric layer 8 by a vacuum deposition method. Through the above steps, predetermined constituent members are formed on the front glass substrate 3, and the front plate 2 is completed.

  On the other hand, the back plate 10 is formed as follows. First, the structure for the address electrode 12 is formed by a method of screen printing a paste containing silver (Ag) material on the rear glass substrate 11 or a method of patterning using a photolithography method after forming a metal film on the entire surface. An address electrode 12 is formed by forming a material layer to be an object and firing it at a desired temperature. Next, a dielectric paste is applied on the rear glass substrate 11 on which the address electrodes 12 are formed by a die coating method so as to cover the address electrodes 12 to form a dielectric paste layer. Thereafter, the base dielectric layer 13 is formed by firing the dielectric paste layer. The dielectric paste is a paint containing powdery dielectric glass, a binder, and a solvent.

  Next, a partition wall forming paste including a partition wall material is applied on the base dielectric layer 13 and patterned into a predetermined shape to form a partition wall material layer, and then fired to form the partition walls 14. Here, as a method of patterning the partition wall paste applied on the base dielectric layer 13, a photolithography method or a sand blast method can be used. Next, the phosphor layer 15 is formed by applying and baking a phosphor paste containing a phosphor material on the base dielectric layer 13 between the adjacent barrier ribs 14 and on the side surfaces of the barrier ribs 14. Through the above steps, predetermined constituent members are formed on the rear glass substrate 11 to complete the rear plate 10.

  In this way, the front plate 2 and the back plate 10 having predetermined constituent members are arranged to face each other so that the scanning electrodes 4 and the address electrodes 12 are orthogonal to each other, and the periphery thereof is sealed with a glass frit, so that a discharge space is obtained. 16 is filled with a discharge gas containing Ne, Xe or the like, thereby completing the PDP 1.

  Next, details of the display electrode 6 and the dielectric layer 8 of the front plate 2 will be described. First, the display electrode 6 will be described. Indium oxide (ITO) having a thickness of about 0.12 μm is formed on the entire surface of the front glass substrate 3 by sputtering, and then stripe-shaped transparent electrodes 4a and 5a having a width of 150 μm are formed by photolithography.

  Further, black metal fine particles of cobalt (Co), nickel (Ni), copper (Cu), metal oxide, and metal composite oxide as black materials are 5 wt% to 40 wt%, and glass materials are 10 wt% to 40 wt%. A photosensitive paste composed of 30% by weight to 60% by weight of a photosensitive organic binder component including a photosensitive polymer, a photosensitive monomer, a photopolymerization initiator, a solvent and the like on the front glass substrate 3 by a printing method or the like. Apply to the entire surface to form a black electrode paste layer.

The glass material of the black electrode paste contains at least 5% by weight to 25% by weight of bismuth oxide (Bi ₂ O ₃ ) so that the softening point of the glass material exceeds 500 ° C. Note that the black metal fine particles, metal oxide, and metal composite oxide of cobalt (Co), nickel (Ni), and copper (Cu) as the black material described above also partially function as a conductive material.

Next, at least 70% to 90% by weight of silver (Ag) particles, 1% to 15% by weight of glass material, and a photosensitive polymer, a photosensitive monomer, a photopolymerization initiator, a solvent, and the like. A photosensitive paste composed of 8% to 30% by weight of an organic binder component is applied onto the black electrode paste layer by a printing method or the like to form a white electrode paste layer. The glass material of the white electrode paste layer contains at least 5 wt% to 25 wt% of bismuth oxide (Bi ₂ O ₃ ) so that the softening point of the glass material exceeds 550 ° C.

  The black electrode paste layer and the white electrode paste layer applied on the entire surface are patterned using a photolithography method, and these are baked at a temperature of 550 ° C. to 600 ° C. to form a black electrode 41b having a line width of about 60 μm, 51b and white electrodes 42b and 52b are formed on the transparent electrodes 4a and 5a.

  As described above, in the practice of the present invention, cobalt (Co), nickel (Ni), and copper (Cu) are used for the black electrodes 41b and 51b. In the prior art, the black electrodes 41b and 51b and the light shielding layer 7 are made of chromium. There is a means for ensuring conductivity and blackness by containing (Cr), manganese (Mn), and iron (Fe). However, the inventors use chromium (Cr), manganese (Mn), and iron (Fe) for the black electrodes 41b and 51b, thereby making contact at the layer interface between the black electrodes 41b and 51b and the white electrodes 42b and 52b. It has been found that the resistance value increases and the resistance value of the entire electrode layer tends to increase. It has also been found that this depends on the glass material component of the black electrodes 41b and 51b, the component of the dielectric layer 8, and the like.

  This phenomenon is explained below. Usually, silver (Ag) contained in the white electrodes 42b and 52b comes into contact with each other by heat treatment in the electrode firing step and the dielectric firing step, and the conductivity of the electrode is developed. However, the components such as the conductive material and the black material contained in the black electrodes 41b and 51b usually move and diffuse to the white electrodes 42b and 52b in the above-described electrode firing and dielectric firing processes, and contact between silver (Ag) is caused. Try to prevent. However, when cobalt (Co), nickel (Ni), and copper (Cu) are used for the black electrodes 41b and 51b, diffusion to the white electrodes 42b and 52b can be suppressed, and as a result, silver (Ag) is Will not interfere with the contact. For this reason, it is considered that the contact resistance value at the layer interface between the black electrodes 41b and 51b and the white electrodes 42b and 52b can be reduced.

  On the other hand, if the black electrode contains the components of chromium (Cr), manganese (Mn), and iron (Fe) as a black material or conductive material, diffusion to the white electrodes 42b and 52b occurs during the firing. The contact between the silver (Ag) is hindered by the components, and this contact resistance increases.

  The prior art also discloses means for ensuring blackness and electrical conductivity by containing ruthenium (Ru) in the black electrodes 41b and 51b and the light shielding layer 7. However, since ruthenium (Ru) is also an expensive rare metal, the use of ruthenium (Ru) leads to an increase in material cost, and in a PDP whose screen size is increasing, a partial increase in cost also has a great effect. As described above, in the practice of the present invention, ruthenium (Ru) is substantially not used, so that it has an advantageous effect from the viewpoint of reducing the material cost and saving resources over the prior art. Become.

The glass material used for the black electrodes 41b and 51b and the white electrodes 42b and 52b has a bismuth oxide (Bi ₂ O ₃ ) content of 5 wt% to 25 wt% as described above. It is preferable that at least one of (MoO ₃ ) and tungsten oxide (WO ₃ ) is contained in an amount of 0.1 wt% to 7 wt%. In place of molybdenum oxide (MoO ₃ ) and tungsten oxide (WO ₃ ), cerium oxide (CeO ₂ ), copper oxide (CuO), cobalt oxide (Co ₂ O ₃ ), vanadium oxide (V ₂ O ₇ ), at least one selected from antimony oxide (Sb ₂ O ₃₎ may be included 0.1 wt to 7% by weight.

Further, as components other than the above, zinc oxide (ZnO) is 0 wt% to 40 wt%, boron oxide (B ₂ O ₃ ) is 0 wt% to 35 wt%, and silicon oxide (SiO ₂ ) is 0 wt% to A material composition that does not include a lead component, such as 15% by weight and aluminum oxide (Al ₂ O ₃ ), such as 0% by weight to 10% by weight, may be included, and the content of these material compositions is not particularly limited, It is the content range of the material composition of the prior art level.

In the present invention, the softening point temperature of the glass material is 500 ° C. or higher, and the firing temperature is 550 ° C. to 600 ° C. When the softening point of the glass material is as low as 450 ° C. to 500 ° C. as in the past, the firing temperature is nearly 100 ° C. higher than that, so that the highly reactive bismuth oxide (Bi ₂ O ₃ ) itself is silver (Ag ) And black metal fine particles, or organic binder components in the paste, reacts violently to generate bubbles in the metal bus electrodes 4b and 5b and the dielectric layer 8, thereby deteriorating the dielectric strength performance of the dielectric layer 8. On the other hand, when the softening point of the glass material is 500 ° C. or more as in the present invention, the reactivity between silver (Ag), black metal fine particles, or organic components and bismuth oxide (Bi ₂ O ₃ ) is reduced, and bubbles are generated. The occurrence of is reduced. However, if the softening point of the glass material is 600 ° C. or higher, the adhesion between the metal bus electrodes 4b and 5b and the transparent electrodes 4a and 5a, the front glass substrate 3 or the dielectric layer 8 is not preferable.

Next, the first dielectric layer 81 and the second dielectric layer 82 constituting the dielectric layer 8 of the front plate 2 will be described in detail. The dielectric material of the first dielectric layer 81 is composed of the following material composition. That is, it contains 5 wt% to 25 wt% of bismuth oxide (Bi ₂ O ₃ ) and 0.5 wt% to 15 wt% of calcium oxide (CaO), and further contains molybdenum oxide (MoO ₃ ) and tungsten oxide ( WO _3), cerium oxide (CeO _2), it contains at least one kind of 0.1 wt% to 7 wt% selected from manganese oxide (MnO _2).

  Furthermore, it contains 0.5 wt% to 12 wt% of at least one selected from strontium oxide (SrO) and barium oxide (BaO).

In place of molybdenum oxide (MoO ₃ ), tungsten oxide (WO ₃ ), cerium oxide (CeO ₂ ), and manganese oxide (MnO ₂ ), copper oxide (CuO), chromium oxide (Cr ₂ O ₃ ), cobalt oxide At least one selected from (Co ₂ O ₃ ), vanadium oxide (V ₂ O ₇ ), and antimony oxide (Sb ₂ O ₃ ) may be contained in an amount of 0.1 wt% to 7 wt%.

Further, as components other than the above, zinc oxide (ZnO) is 0 wt% to 40 wt%, boron oxide (B ₂ O ₃ ) is 0 wt% to 35 wt%, and silicon oxide (SiO ₂ ) is 0 wt% to A material composition that does not include a lead component, such as 15% by weight and aluminum oxide (Al ₂ O ₃ ), such as 0% by weight to 10% by weight, may be included, and the content of these material compositions is not particularly limited, It is the content range of the material composition of the prior art level.

  A dielectric material powder is produced by pulverizing a dielectric material composed of these composition components with a wet jet mill or a ball mill so that the average particle size is 0.5 μm to 2.5 μm. Next, the dielectric material powder 55 wt% to 70 wt% and the binder component 30 wt% to 45 wt% are well kneaded with three rolls to produce a first dielectric layer paste for die coating or printing. To do.

  Then, using this first dielectric layer paste, the front glass substrate 3 is printed by a die coating method or a screen printing method so as to cover the display electrode 6 and dried, and then a temperature slightly higher than the softening point of the dielectric material. Is fired at 575 ° C to 590 ° C.

Next, the second dielectric layer 82 will be described. The dielectric material of the second dielectric layer 82 is composed of the following material composition. That is, it contains 5 to 25% by weight of bismuth oxide (Bi ₂ O ₃ ) and 6.0 to 28% by weight of barium oxide (BaO), and further contains molybdenum oxide (MoO ₃ ) and tungsten oxide (WO ₃ ) 0.1 to 7% by weight of at least one selected from cerium oxide (CeO ₂ ) and manganese oxide (MnO ₂ ) is contained.

  Furthermore, it contains 0.8 wt% to 17 wt% of at least one selected from calcium oxide (CaO) and strontium oxide (SrO).

In place of molybdenum oxide (MoO ₃ ), tungsten oxide (WO ₃ ), cerium oxide (CeO ₂ ), and manganese oxide (MnO ₂ ), copper oxide (CuO), chromium oxide (Cr ₂ O ₃ ), cobalt oxide At least one selected from (Co ₂ O ₃ ), vanadium oxide (V ₂ O ₇ ), and antimony oxide (Sb ₂ O ₃ ) may be contained in an amount of 0.1 wt% to 7 wt%.

Further, as components other than the above, zinc oxide (ZnO) is 0 wt% to 40 wt%, boron oxide (B ₂ O ₃ ) is 0 wt% to 35 wt%, and silicon oxide (SiO ₂ ) is 0 wt% to A material composition that does not include a lead component, such as 15% by weight and aluminum oxide (Al ₂ O ₃ ), such as 0% by weight to 10% by weight, may be included, and the content of these material compositions is not particularly limited, It is the content range of the material composition of the prior art level.

  A dielectric material powder is produced by pulverizing a dielectric material composed of these composition components with a wet jet mill or a ball mill so that the average particle size is 0.5 μm to 2.5 μm. Next, the dielectric material powder 55 wt% to 70 wt% and the binder component 30 wt% to 45 wt% are well kneaded with three rolls to produce a second dielectric layer paste for die coating or printing. To do. Then, the second dielectric layer paste is used to print on the first dielectric layer 81 by a screen printing method or a die coating method and then dried, and then, a temperature slightly higher than the softening point of the dielectric material is 550 ° C. Bake at ~ 590 ° C.

  Since the effect of improving the panel brightness and reducing the discharge voltage becomes more significant as the thickness of the dielectric layer 8 is smaller, it is desirable to set the thickness as small as possible within the range where the withstand voltage does not decrease. . From the viewpoint of such conditions and visible light transmittance, in the embodiment of the present invention, the film thickness of the dielectric layer 8 is set to 41 μm or less, the first dielectric layer 81 is 5 μm to 15 μm, and the second dielectric The layer 82 is 20 μm to 36 μm.

As described above, the amount of bismuth oxide (Bi ₂ O ₃ ) contained in the dielectric layer 8 in the present invention is 5% by weight to the first dielectric layer 81 and the second dielectric layer 82 as described above. 25% by weight. By setting the amount of bismuth oxide (Bi ₂ O ₃ ) in the dielectric layer 8 within this range, the blackness of the PDP can be improved, and a desired softening point and dielectric constant as the dielectric layer 8 can be obtained. be able to. The first dielectric layer 81 and the second dielectric layer 82 need not have the same amount of bismuth oxide (Bi ₂ O ₃ ).

  The PDP front plate manufactured in this way has a good blackness and a low contact resistance value of the metal electrode, and when used as a panel, a PDP having a good contrast when displaying an image can be obtained.

(Example)
In order to confirm the effect of the embodiment of the present invention, a test sample was prepared and evaluated with a front plate configuration suitable for 42-inch high vision.

  The evaluation of blackness is performed by forming a light shielding layer 7 on a glass substrate by the above-described method, and further preparing a sample in which the dielectric layer 8 is formed by the above-described method so as to cover it. It was.

Generally, the lightness L ^* is obtained by a method defined in JISZ8722 (color measurement method) and JISZ8729 (color display method—L ^* a ^* b ^* color system and L ^* u ^* v ^* color system). In the embodiment of the present invention, the blackness is expressed by using an L ^* a ^* b ^* display system, and a low L ^* value indicates that the blackness is strong (good). When the L ^* value is low, the contrast is high when an image is displayed on the PDP. In the embodiment of the present invention, the L ^* value is measured using a Nippon Denshoku Co., Ltd. spectral color difference meter NF999.

  The measurement sample is patterned by the same method as described above so that the measurement area is 10 mm square, and the measurement is performed by stacking a white plate on the film surface side and measuring from the glass substrate side (image display side). An average value obtained by measuring three points by changing the position in the substrate is taken as a measurement result.

FIG. 3 is a diagram showing a change in the blackness L ^* value of the light shielding layer 7 with respect to the amount of bismuth oxide (Bi ₂ O ₃ ) of the dielectric layer 8. Under the measurement conditions of the inventors, a good contrast was obtained when the L ^* value of the light shielding layer 7 was 10 or less in the PDP image display. Based on this, as shown in FIG. 3, the L ^* value is 10 or less because the amount of bismuth oxide (Bi ₂ O ₃ ) in the dielectric layer 8 is 5 wt% to 30 wt%. .

Although the detailed cause for this phenomenon is unknown, the dielectric layer 8 (in particular, the first dielectric in the embodiment of the present invention) is in contact with the rear surface of the light shielding layer 7 or the end of the black electrodes 41b and 51b. This is considered to be caused by the influence of bismuth oxide (Bi ₂ O ₃ ) in the layer 81). Due to this influence, black metal fine particles, metal oxides, and metal composite oxides of cobalt (Co), nickel (Ni), and copper (Cu), which are black materials, diffuse to the front glass substrate 3 side, that is, the image display surface, and become black. I guess it is improving.

  For the evaluation of the contact resistance value of the display electrode 6, the transparent electrodes 4a and 5a, the black electrodes 41b and 51b, and the white electrodes 42b and 52b are respectively formed on the glass substrate by the above-described method, and further, the electrodes are covered. A test sample in which the dielectric layer 8 was formed by the method described above was prepared, and the performance was evaluated by measuring the resistance value with a tester. In addition, in order to omit the contact resistance of the dielectric itself, the sample is formed with an extraction terminal, and the influence of the contact resistance of the dielectric layer 8 is excluded.

FIG. 4 is a graph showing a difference in contact resistance characteristics with respect to the components contained in the black electrodes 41b and 51b. In addition, the contact resistance value was compared and examined by setting the content of bismuth oxide (Bi ₂ O ₃ ) in the dielectric layer 8 to 25 wt% and 40 wt%. The contact resistance value is that the dielectric layer 8 has a bismuth oxide (Bi ₂ O ₃ ) content of 40% by weight, and the black electrodes 41b and 51b contain chromium (Cr), manganese (Mn), and iron (Fe). The measurement result of the sample is shown as a relative value with 1.

  As a result, compared with the case where chromium (Cr), manganese (Mn), and iron (Fe) are contained as components of the black electrodes 41b and 51b, cobalt (Co) and nickel (Ni) used in the embodiment of the present invention are used. It can be seen that the contact resistance decreases when copper (Cu) is contained as a component of the black electrodes 41b and 51b. As described above, when cobalt (Co), nickel (Ni), and copper (Cu) are contained as components of the black electrodes 41b and 51b, diffusion to each electrode layer is reduced, and silver (Ag) particles This is probably because the contact is not hindered.

The contact resistance value also depends on the content of bismuth oxide (Bi ₂ O ₃ ) in the dielectric layer 8, and as shown in FIG. 4, the amount of bismuth oxide (Bi ₂ O ₃ ) is 25 wt. If it is%, the contact resistance value decreases.

Furthermore, in the embodiment of the present invention, the change in contact resistance with respect to the bismuth oxide (Bi ₂ O ₃ ) content in the glass material of the white electrodes 42 b and 52 b and the bismuth oxide (Bi ₂ O ₃ ) content in the dielectric layer 8. I also investigated. The results are shown in FIGS. FIG. 5 shows the contact resistance with respect to the bismuth oxide (Bi ₂ O ₃ ) content of the dielectric layer 8 when the bismuth oxide (Bi ₂ O ₃ ) content in the glass material of the white electrodes 42b and 52b is 25% by weight. It is a figure which shows the change of a value. On the other hand, FIG. 6 when bismuth oxide (Bi ₂ O ₃₎ content of the dielectric layer 8 is 25% by weight, white electrodes 42b, for bismuth oxide (Bi ₂ O ₃₎ content in the glass material 52b It is a figure which shows the change of a contact resistance value. Similarly to FIG. 4, the dielectric layer 8 has a bismuth oxide (Bi ₂ O ₃ ) content of 40% by weight, and the black electrodes 41b and 51b contain chromium (Cr), manganese (Mn), iron (Fe). The measurement result of the sample is shown as a relative value with 1.

In the embodiment of the present invention, if the contact resistance value is 0.9 or less in relative value, the increase amount of the resistance value of the entire display electrode is also small, and the influence on the applied voltage necessary for image display can be suppressed low. As shown in FIG. 5, the contact resistance value is 0.9 or less because the dielectric layer 8 has a bismuth oxide (Bi ₂ O ₃ ) content of 5 wt% to 30 wt%. On the other hand, the dielectric layer 8 is required to have a low dielectric constant from the viewpoint of reactive power during discharge. From this, it is more desirable that the content of bismuth oxide (Bi ₂ O ₃ ) in the dielectric layer 8 is 25% by weight or less.

As shown in FIG. 6, the contact resistance value was 0.9 or less because the bismuth oxide (Bi ₂ O ₃ ) content of the white electrodes 42b and 52b was 5 wt% to 40 wt%. On the other hand, from the viewpoint of the softening point during the firing process, the content of bismuth oxide (Bi ₂ O ₃ ) in the white electrodes 42b and 52b is more preferably 25% by weight or less.

As described above, in the embodiment of the present invention, the front plate in which the display electrode and the dielectric layer are formed on the glass substrate and the back plate in which the electrode, the barrier rib, and the phosphor layer are formed on the substrate are arranged to face each other. And the display electrode is formed of a plurality of layers including a metal electrode layer containing at least silver and a glass material, and the dielectric layer includes bismuth oxide ( The content of Bi ₂ O ₃ ) is 5 wt% or more and 25 wt% or less, and the content of bismuth oxide (Bi ₂ O ₃ ) in the glass material of the metal electrode layer is 5 wt% or more and 25 wt% or less. The black layer contains cobalt (Co), nickel (Ni), copper (Cu), or an oxide thereof. Thereby, the contact resistance value of the display electrode can be reduced, and a PDP having good blackness and high image display quality can be realized. Furthermore, the PDP according to the embodiment of the present invention is an environment-friendly PDP that can suppress the cost of materials and does not contain lead (Pb).

  As described above, the present invention can realize a PDP having a good image display contrast and considering environmental issues, and is useful for a display device having a large screen.

The perspective view which shows the structure of PDP in embodiment of this invention Sectional drawing which shows the structure of the front plate of the PDP Characteristic diagram showing the blackness of the light shielding layer relative to the amount of bismuth oxide in the dielectric layer Characteristic diagram showing the contact resistance value for the components contained in the black electrode Characteristic diagram showing the contact resistance value for the bismuth oxide content of the dielectric layer Characteristic diagram showing contact resistance value against bismuth oxide content in glass material of white electrode

Explanation of symbols

1 PDP
DESCRIPTION OF SYMBOLS 2 Front plate 3 Front glass substrate 4 Scan electrode 4a, 5a Transparent electrode 4b, 5b Metal bus electrode 5 Sustain electrode 6 Display electrode 7 Light shielding layer 8 Dielectric layer 9 Protective layer 10 Back plate 11 Back glass substrate 12 Address electrode 13 Base dielectric Body layer 14 Partition 15 Phosphor layer 16 Discharge space 41b, 51b Black electrode 42b, 52b White electrode 81 First dielectric layer 82 Second dielectric layer

Claims (2)

A front plate with a display electrode and dielectric layer formed on a glass substrate and a back plate with electrodes, barrier ribs and phosphor layers formed on the substrate are placed opposite to each other and sealed around to form a discharge space. A plasma display panel,
The display electrode comprises at least a plurality of layers including a metal electrode layer containing silver and a glass material,
The content of bismuth oxide (Bi ₂ O ₃ ) in the dielectric layer is 5 wt% or more and 25 wt% or less, and the content of bismuth oxide (Bi ₂ O ₃ ) in the glass material of the metal electrode layer is A plasma display panel, wherein the content is 5% by weight or more and 25% by weight or less. The plasma display panel according to claim 1, wherein the black layer contains cobalt (Co), nickel (Ni), copper (Cu), or an oxide thereof.

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