JP4747725B2 - Plasma display panel - Google Patents

Description

  The present invention relates to a plasma display panel known as a display device, and more particularly to a plasma display panel realizing high image quality.

  In recent years, expectations for large screens and wall-mounted televisions are increasing as interactive information terminals, and there are many display devices such as liquid crystal display panels, field emission displays, and electroluminescence displays. Among these display devices, the plasma display panel (hereinafter referred to as “PDP”) is a thin display device with excellent visibility because it is self-luminous and can display beautiful images and can be easily enlarged. Development for higher definition and larger screen is underway.

  PDP is broadly divided 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. However, due to high definition, large screen, and ease of manufacturing, At present, AC type and surface discharge type PDPs have become the mainstream.

  The PDP is formed from a front plate formed of a constituent such as a display electrode, a dielectric layer, a protective layer made of MgO on a transparent substrate, and a constituent such as an address electrode, a dielectric layer, a partition wall, and a phosphor layer on the substrate. And a back plate.

  On the other hand, from the influence on the environment, it is required to use glass materials that do not contain lead for the glass material forming the dielectric layer of the PDP, and such glass materials are disclosed (for example, Patent Document 1, Patents). Reference 2).

In addition, when the display electrode made of a silver electrode is covered with a dielectric layer, a phenomenon occurs in which the substrate turns yellow. In order to suppress these phenomena, an oxidizing agent is contained in the paste of the glass material forming the dielectric layer. The example which mixes is disclosed (for example, refer patent document 3).
JP 2004-35297 A JP 2005-41734 A JP 2002-25341 A

  The dielectric layer of the PDP has high transparency of the dielectric layer, high insulation resistance without bubbles in the dielectric layer, and having an appropriate dielectric constant as a capacitor, Furthermore, it is required that reaction with the electrode is suppressed.

However, when the dielectric layer is formed of a Bi ₂ O ₃ glass material not containing lead, the dielectric constant of the dielectric layer increases and the capacitance of the dielectric layer increases. It had the problem of increasing. On the other hand, when the dielectric layer is formed of a glass material containing R ₂ O (R is at least one selected from Li, Na, and K), the dielectric constant is not increased. There is a large amount of non-bridging oxygen, and silver ions diffused from the previously formed silver electrode are reduced through the non-bridging oxygen to form a silver colloid, and the dielectric layer is colored yellow. It had the problem of generating a phenomenon called “hen”.

  Such yellowing not only affects the image quality of the PDP, but also causes bubbles in the dielectric layer, thereby reducing the insulation resistance of the dielectric layer. Moreover, the method of mixing an oxidizing agent for the purpose of suppressing these yellowing has problems such as impairing the permeability of the dielectric layer.

  The present invention solves the above-mentioned problems, and realizes a PDP having excellent display quality with no discoloration and the like by using a dielectric layer containing no lead, satisfying transmittance, insulation resistance and dielectric constant. With the goal.

In order to solve the above problems, the PDP of the present invention is a PDP in which a dielectric layer is provided so as to cover the display electrode, and the dielectric layer does not contain a lead component but contains Bi ₂ O ₃ , And a first dielectric layer covering the display electrode and a second dielectric layer covering the first dielectric layer. The first dielectric layer is composed of MO (MO is CeO ₂ , CuO, MnO ₂ , Cr ₂ O ₃ , Co ₂ O ₃ , V ₂ O ₃ , MoO ₃ ), R ₂ O (R is at least one selected from Li, Na, K), and The two dielectric layers contain R ₂ O (R is at least one selected from Li, Na, K), and MO (MO is CeO ₂ , CuO, MnO ₂ , Cr ₂ O ₃ , Co ₂ O ₃ , V ₂ O ₃ and at least one selected from MoO ₃ ) are not contained.

  With this configuration, the entire dielectric layer can be made of a glass material that does not contain a lead component, a dielectric layer that satisfies the dielectric constant and insulation resistance is realized, and a PDP with excellent display quality is provided. can do.

  According to the PDP of the present invention, the entire dielectric layer is made of an environmentally friendly glass material that does not contain lead, and a PDP with excellent display quality that does not have a decrease in transmittance or a decrease in insulation resistance due to generation of bubbles is realized. can do.

  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 panel 2 made of a front glass substrate 3 and a rear panel 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 neon and xenon at a pressure of 400 Torr to 600 Torr.

  On the front glass substrate 3 of the front panel 2, a pair of strip-shaped display electrodes 6 each consisting of the scanning electrodes 4 and the sustain electrodes 5 and a plurality of black stripes (light shielding layers) 7 are arranged in parallel to 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 panel 10, a plurality of strip-like address electrodes 12 are arranged in parallel to each other in a direction orthogonal to the scan electrodes 4 and the sustain electrodes 5, and this is covered with a base dielectric layer 13. is doing. 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. 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 for each address electrode 12. 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.

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. Scan electrode 4 and sustain electrode 5 are configured by a transparent electrode made of indium tin oxide (ITO), tin oxide (SnO ₂ ), or the like, and a metal bus electrode made of silver paste or the like formed thereon. These electrodes are formed by patterning using a photolithography method or the like. These electrode material layers are fired and solidified at a desired temperature. Similarly, the light shielding layer 7 is formed by screen printing a paste containing a black pigment or by forming a black pigment on the entire surface of the glass substrate, patterning it using a photolithography method, and baking it.

  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 material 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. The dielectric paste is a paint containing a dielectric material such as glass powder, 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 components (scanning electrode 4, sustaining electrode 5, light shielding layer 7, dielectric layer 8, and protective layer 9) are formed on front glass substrate 3, and front panel 2 is completed.

  On the other hand, the back panel 10 is formed as follows. First, a material layer that becomes a constituent for the address electrode 12 by a method of screen printing a silver paste on the back glass substrate 11 or a method of patterning using a photolithography method after forming a metal film on the entire surface. Are formed and fired at a desired temperature to form the address electrode 12. 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 a dielectric material such as glass powder, a binder and a solvent.

  Next, a partition wall forming paste containing a partition wall material is applied onto 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 faces of the barrier ribs 14. Through the above steps, the rear panel 10 having predetermined components on the rear glass substrate 11 is completed.

  In this way, the front panel 2 and the back panel 10 provided with 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 neon, xenon, or the like, thereby completing the PDP 1.

  Next, the dielectric layer 8 that is a feature of the present invention will be described in detail. FIG. 2 is a cross-sectional view of front panel 2 showing the configuration of dielectric layer 8 of the PDP in the embodiment of the present invention. 2 is shown upside down from FIG. As shown in FIG. 2, display electrodes 6 and black stripes 7 made of scanning electrodes 4 and sustain electrodes 5 are formed in a pattern on a front glass substrate 3 manufactured by a float process or the like. Scan electrode 4 and sustain electrode 5 are each composed of transparent electrodes 4a and 5a and metal bus electrodes 4b and 5b formed on transparent electrodes 4a and 5a. 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 such as a silver material.

  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 black stripe 7, and a first dielectric layer. The second dielectric layer 82 formed on the layer 81 has at least two layers. A protective layer 9 is formed on the second dielectric layer 82.

In the embodiment of the present invention, the first dielectric layer 81 is formed using a dielectric glass material containing Bi ₂ O ₃ , and the second dielectric layer 82 is formed of R ₂ O (R is Li, Na, K). It is formed using a dielectric glass material containing at least one selected from Further, the first dielectric layer 81 that contacts with the metal bus electrodes 4b and 5b to form an interface has a dielectric glass of MO (MO is CeO ₂ , MnO ₂ , Cr ₂ O ₃ , CuO, Co ₂ O ₃ , V ₂ O ₃ or at least one selected from MoO ₃ ) may be contained. Therefore, the dielectric layer 8 composed of the first dielectric layer 81 and the second dielectric layer 82 can be a dielectric layer 8 that does not contain a lead component.

  The first dielectric layer 81 and the second dielectric layer 82 can be formed by the following method. That is, a dielectric paste composed of glass powder of each dielectric glass and a solvent containing resin is applied on the front glass substrate 3 on which the display electrodes 6 and the black stripes 7 are formed by a screen printing method or the like. After drying, baking is performed at 450 ° C. to 600 ° C. to form each dielectric layer.

  As another method, a dielectric paste composed of glass powder of each dielectric glass and a solvent containing a resin is formed on a film, and the display electrode 6 and the black stripe 7 are formed on the front surface. A method in which the respective dielectric layers are formed by transferring onto the glass substrate 3 and then firing at 450 ° C. to 600 ° C. is also applicable.

In the embodiment of the present invention, a dielectric glass material containing R ₂ O (R is at least one selected from Li, Na, and K) is used for the second dielectric layer 82, and the first dielectric layer 81 is formed using a dielectric glass material containing Bi ₂ O ₃ . Therefore, since the dielectric constant of the second dielectric layer 82 is smaller than the dielectric constant of the first dielectric layer 81, the second dielectric layer 82 is made to be the first dielectric layer in order to optimize the dielectric constant of the dielectric layer 8. It may be formed thicker than the layer 81.

(Example)
As a specific example of the embodiment of the present invention, a PDP in which the material components of the dielectric glass of the first dielectric layer 81 and the second dielectric layer 82 were changed was produced and evaluated for the following items.

(Evaluation Experiment 1)
In order to evaluate the degree of yellowing due to the difference in dielectric glass material, the first dielectric layer and the second dielectric layer are formed on the front glass substrate on which the silver electrode is formed, and the b * value is measured using a color difference meter. Were evaluated and compared. In addition, it shows that discoloration is so large that b * value is large.

(Evaluation Experiment 2)
In order to evaluate the dielectric strength voltage of the dielectric layer, a dielectric breakdown test was performed on the dielectric layer formed with the first dielectric layer and the second dielectric layer. In the dielectric breakdown test of the dielectric layer, a metal plate is placed on the dielectric layer 8 of the front panel 2 in a rare gas space, and an AC voltage is applied between the display electrode 6 and the metal plate to evaluate the breakdown voltage. did.

(Evaluation Experiment 3)
The dielectric constant of the dielectric layer was measured using a LCR meter for the relative dielectric constant at a frequency of 1 MHz.

  Table 1 shows the material component ratio of the dielectric glass for forming the first dielectric layer 81 and the second dielectric layer 82 and the dielectric constant of the material in this embodiment.

In Table 1, A and B are dielectric glass materials for forming the second dielectric layer 82, and C, D, and E are dielectric glass materials for forming the first dielectric layer 81. . As shown in Table 1, the dielectric glass materials C, D, and E of the first dielectric layer 81 are mainly composed of Bi ₂ O ₃ and contain a small amount of CeO ₂ and MnO ₂ as MO materials. The dielectric glass materials A and B of the second dielectric layer 82 contain an R ₂ O glass material and do not contain an MO material.

  Table 2 shows examples of the present invention and comparative examples as combinations of dielectric layers produced using the material components shown in Table 1.

  As shown in Table 2, each dielectric layer is a lead-free dielectric layer, the dielectric layers of Examples 1 to 4 as examples of the present invention, and a comparison as a comparative example with respect to the examples. Examples 1 to 4 were prepared, and the above b * value, dielectric breakdown test, and dielectric layer dielectric constant evaluation experiment were performed.

FIG. 3 is a diagram showing the result of b * value indicating the degree of yellowing of the dielectric layer of the PDP according to the embodiment of the present invention. It can be seen that Comparative Examples 1 to 4 have a larger b * value than Examples 1 to 4 of the present invention. In particular, in Comparative Examples 3 and 4, when the metal bus electrodes 4b and 5b and the dielectric glass material of the R ₂ O component are in contact with each other, a large amount of silver colloid of the metal bus electrodes 4b and 5b is generated and yellowing proceeds. As a result, the b * value is significantly increased to 5 or more. On the other hand, in Comparative Examples 1 and 2, the b * value is larger than 3 although the yellowing is suppressed compared to Comparative Examples 3 and 4.

On the other hand, in the embodiment of the present invention, as shown in Embodiments 1, 2, 3, and 4, the first dielectric layer 81 is formed using a dielectric glass material mainly composed of Bi ₂ O ₃ , and the second The dielectric layer 82 is formed using a dielectric glass material containing R ₂ O (R is at least one selected from Li, Na, and K). Further, the first dielectric layer 81 that contacts with the metal bus electrodes 4b and 5b to form an interface has a dielectric glass of MO (MO is CeO ₂ , MnO ₂ , Cr ₂ O ₃ , CuO, Co ₂ O ₃ , At least one selected from V ₂ O ₃ and MoO ₃ ). As a result, the b ^* value can be suppressed to 2 or less by including an oxide component such as CeO ₂ or MnO ₂ in the lower dielectric glass. In addition, it is considered that the yellowing is suppressed by these oxides because reduction of silver deposited from the silver electrode which is a metal bus electrode is suppressed.

  FIG. 4 is a diagram showing the result of the dielectric breakdown test of the dielectric layer of the PDP according to the embodiment of the present invention, and shows the number of dielectric breakdowns within a predetermined area. From the results of FIG. 4, it can be seen that the dielectric layer configurations of Comparative Examples 1, 2, 3, and 4 cannot ensure sufficient withstand voltage performance. As shown in FIG. 3 showing the degree of yellowing, the cause of this is the generation of silver colloid when yellowing occurs, and the dielectric breakdown voltage performance of the dielectric layer due to the generation of bubbles as a result. It is thought that it has deteriorated.

  On the other hand, in Examples 1, 2, 3, and 4, since there is no cause of these yellowing occurrences, it is considered that sufficient withstand voltage performance as a dielectric layer can be secured.

  The dielectric constants of Examples 1 to 4 of the present invention are all values of 11 or less, and are values that can be driven without increasing the power consumption of the PDP in actual use. Yes.

In the above-described embodiment, Ce ₂ O ₃ or MnO ₂ is contained in the first dielectric layer 81 as the material of the MO component, but Co ₂ O ₃ , CuO, Cr ₂ O ₃ , V ₂ O _3, the same effect also contain MoO ₃ is confirmed that the obtained.

In the present invention, a dielectric layer in contact with a silver electrode or the like is a dielectric glass material mainly composed of Bi ₂ O ₃ containing no lead component, and further contains a trace amount of MO component, and lead is added to the upper layer. A two-layer structure in which a dielectric layer of R ₂ O not included is provided. As a result, it is possible to realize a dielectric layer for PDP that does not cause yellowing and does not deteriorate the dielectric strength performance.

  As described above, the PDP of the present invention does not cause yellowing of the dielectric layer and does not deteriorate the withstand voltage performance, realizes a PDP excellent in display quality, and is useful for a large screen display device.

The perspective view which shows the structure of PDP in embodiment of this invention Sectional drawing of the front panel showing the configuration of the dielectric layer of the PDP The figure which shows the result of b * value which shows the degree of yellowing of the dielectric material layer of the PDP The figure which shows the result of the dielectric breakdown test of the dielectric material layer of the PDP

Explanation of symbols

1 PDP
2 Front panel 3 Front glass substrate 4 Scan electrode 4a, 5a Transparent electrode 4b, 5b Metal bus electrode 5 Sustain electrode 6 Display electrode 7 Black stripe (light shielding layer)
DESCRIPTION OF SYMBOLS 8 Dielectric layer 9 Protective layer 10 Back panel 11 Back glass substrate 12 Address electrode 13 Base dielectric layer 14 Partition 15 Phosphor layer 16 Discharge space 81 1st dielectric layer 82 2nd dielectric layer

Claims (1)

A plasma display panel that covers a display electrode and is provided with a dielectric layer,
The dielectric layer includes a first dielectric layer that does not contain a lead component, contains Bi ₂ O ₃ , covers the display electrode , and a second dielectric layer covers the first dielectric layer. And
The first dielectric layer contains MO (MO is at least one selected from CeO ₂ , CuO, MnO ₂ , Cr ₂ O ₃ , Co ₂ O ₃ , V ₂ O ₃ , MoO ₃ ), and R _2. Does not contain O (R is at least one selected from Li, Na, K),
The second dielectric layer contains R ₂ O (R is at least one selected from Li, Na, and K), and MO (MO is CeO ₂ , CuO, MnO ₂ , Cr ₂ O ₃ , Co ₂ O). ₃ , at least one selected from V ₂ O ₃ and MoO ₃ ).

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