JP5076303B2 - Plasma display panel - Google Patents

Description

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

  In recent years, expectations for large screens and wall-mounted televisions have increased, and display devices such as plasma display panels (PDP), liquid crystal display panels (LCD), field emission displays (FED), electroluminescence displays (EL), etc. There are many things. Among these display devices, in particular, PDPs are attracting attention as thin display devices with excellent visibility because they are self-luminous and can display beautiful images and are easy to make large screens. Development for screen creation is in progress.

  This PDP is broadly divided into AC type and DC type in terms of driving, and there are two types of discharge types, a surface discharge type and a counter discharge type. From the viewpoint of high definition, large screen, and ease of manufacturing. At present, AC type and surface discharge type PDPs are becoming mainstream.

  The AC type surface discharge type PDP is generally formed by forming a large number of discharge cells between a front plate and a back plate arranged to face each other. In the front plate, a plurality of pairs of scan electrodes and sustain electrodes are formed in parallel as display electrodes on a transparent substrate such as glass, and a dielectric layer and a protective layer are formed so as to cover these display electrodes. Note that MgO is used as a material for the protective layer.

In the back plate, a plurality of address electrodes are formed in parallel with each other on a substrate, and a dielectric layer is formed so as to cover them. A plurality of barrier ribs are formed on the dielectric layer in parallel with the address electrodes, and a phosphor layer is formed on the surface of the dielectric layer and the side surfaces of the barrier ribs. Then, the front plate and the rear plate are sealed so that the display electrode and the data electrode cross each other, and a discharge gas is sealed in a discharge space inside the PDP at a pressure of, for example, about 66500 Pa (about 500 Torr). (For example, refer nonpatent literature 1).
Heki Uchiike and Shigeo Miko, “All about Plasma Displays”, Industrial Research Council, Inc., May 1, 1997, p79-p80

  In the above-described PDP, there may be a problem that the partition wall is peeled off. In some cases, the gas adhering to the barrier ribs adversely affects the discharge characteristics in the panel.

  The above problems become more prominent when higher efficiency and higher definition are required, and as a result, it is necessary to reduce the width of the partition wall. That is, in order to ensure luminance even in high definition, it is necessary to secure a discharge space, and for that purpose, it is necessary to reduce the width of the barrier ribs. As the wall becomes thinner, the strength against impacts such as dropping and vibration becomes insufficient, and the high definition of the partition wall increases the surface area of the partition wall and increases the amount of gas adsorbed there. is there.

  The present invention has been made in view of the above circumstances, and has an object to realize a partition structure having sufficient strength and suppressed gas generation, thereby realizing a high-efficiency and high-quality PDP. To do.

In order to achieve the above object, a plasma display panel of the present invention includes a front plate and a back plate that are opposed to each other with a partition wall interposed therebetween so as to form a discharge space, and the partition wall has at least a two-layer structure, Both of the two layers include three or more types of inorganic materials, and in the two layers, the lower layer is formed using an inorganic material having a lower softening point than the upper layer, and the softening point is the highest among the three or more types of inorganic materials. A low inorganic material is in the form of particles whose particle size distribution is smaller than that of other types of inorganic materials.

  According to the PDP of the present invention, it is possible to realize a partition structure with sufficient strength and suppressed gas generation, and thus, a highly efficient and high quality PDP can be realized.

That is, the invention according to claim 1 of the present invention includes a front plate and a back plate that are arranged to face each other with a partition wall interposed therebetween so as to form a discharge space, and the partition wall has at least a two-layer structure, Both layers include three or more types of inorganic materials, and in the two layers, a lower layer is formed using an inorganic material having a lower softening point than the upper layer, and the softening point is the lowest among the three or more types of inorganic materials. The inorganic material is a plasma display panel whose particle size distribution is smaller than that of other types of inorganic materials.

The invention according to claim 2 is the invention according to claim 1, wherein the partition wall has a cross-girder shape having different heights in the vertical direction and the horizontal direction, and has a portion having a different height as a boundary. a two-layer structure.

  FIG. 1 is a cross-sectional perspective view showing a schematic configuration of a plasma display panel according to an embodiment of the present invention.

  As shown in FIG. 1, the PDP includes a front plate 1 and a back plate 2.

  The front plate 1 is, for example, a stripe-shaped display electrode 6 that is paired with a scan electrode 4 and a sustain electrode 5 on a transparent front substrate 3 such as a glass substrate made of sodium borosilicate glass by a float method. And a dielectric layer 7 is formed so as to cover the display electrode 6 group, and a protective film (protective layer) 8 made of MgO is formed on the dielectric layer 7. Has been. Scan electrode 4 and sustain electrode 5 are composed of transparent electrodes 4a and 5a, and bus electrodes 4b and 5b made of Cr / Cu / Cr or Ag electrically connected to transparent electrodes 4a and 5a, respectively. Has been.

  In addition, the back plate 2 forms an address electrode 10 in a direction crossing the display electrode 6 on a back side substrate 9 disposed opposite to the substrate 3, and the dielectric layer 11 covers the address electrode 10. Is forming. For example, stripe-shaped partition walls 12 are formed on the dielectric layer 11.

  Here, in the PDP according to the embodiment of the present invention described above, the partition wall 12 includes at least three kinds of inorganic materials.

  A phosphor layer 13 is formed on the side surfaces between the partition walls 12 and the surface of the dielectric layer 11. For color display, the phosphor layer 13 is usually arranged in order of three colors of red, green, and blue.

  Then, the front plate 1 and the back plate 2 are arranged so as to face each other with the partition wall 12 interposed therebetween so that the display electrode 6 and the address electrode 10 intersect and form a minute discharge space inside, and the periphery is sealed. The PDP is configured by sealing with a sealing frit as a deposition member, and sealing the discharge space with a discharge gas obtained by mixing neon, xenon, helium, and the like at a pressure of about 66500 Pa (500 Torr).

  As described above, the discharge space of the PDP is partitioned into a plurality of sections by the barrier ribs 12, and a unit light emitting region and a portion between the barrier ribs 12 and the display electrodes 6 and the address electrodes 10 are orthogonal to each other. A plurality of discharge cells are formed. Then, a discharge is generated by a periodic voltage applied to the display electrode 6 and the address electrode 10, and an image is displayed by irradiating the phosphor layer 13 with ultraviolet rays resulting from the discharge and converting it into visible light.

  FIG. 2 is a plan view showing a schematic configuration of the image display unit of the PDP according to the embodiment of the present invention described above. As shown in FIG. 2, the scan electrodes 4 and the sustain electrodes 5 are alternately arranged in the column direction so as to be adjacent to each other with a discharge gap 14 in each line of the matrix display. Here, a region surrounded by the barrier ribs 12 becomes a discharge cell 15 which is a unit light emitting region. Further, a black stripe (not shown) may be formed in the non-light emitting region 16 for the purpose of improving the contrast.

  Here, as shown in FIG. 3 as a schematic cross-sectional view, the partition wall of the conventional PDP has an inorganic component 12a called a filler having a very high softening point (or melting point) (for example, the softening point of alumina used for the filler is 1800 ° C.) and an inorganic component (glass) 12b that softens at the firing temperature of the partition wall (for example, 550 ° C.) (composition distribution can be confirmed by measuring the cross section with EDAX or the like) According to the PDP of one embodiment of the present invention, since the partition wall 12 contains three or more kinds of inorganic materials, the viscosity at the firing temperature (for example, 600 ° C.) of the partition wall varies depending on the respective inorganic materials. The sintered state can be made denser than in the case of the conventional material configuration.

  Here, as the three or more kinds of inorganic materials, one is at least one selected from, for example, titanium oxide, alumina, barium titanate, zirconia, cordierite, mullite, and high-melting glass powder. An inorganic component filler (first inorganic material), which is included in a conventional partition wall. This is used to maintain the shape of the partition wall 12 and hardly changes at the firing temperature of the partition wall 12. Another of the three or more types of inorganic materials is, for example, glass (second inorganic material) having a softening point substantially equal to the firing temperature, which is also a material included in a conventional partition wall. The other is an inorganic material (third inorganic material) having a softening point lower than that of the second inorganic material. Due to the presence of the third inorganic material, the third inorganic material softens before the firing temperature of the partition 12 reaches the maximum temperature (a temperature substantially equal to the softening point of the second inorganic material), As the viscosity rises, the viscosity is greatly reduced to provide fluidity, and the molten third material flows into the gaps between the materials of the second inorganic component, thereby improving the sintered state of the partition wall 12. can do. Thereby, the intensity | strength of the partition 12 can be improved.

  Here, in the conventional partition, although there are some differences depending on how to select the softening point of the inorganic component and the setting of the firing temperature, there are cases where voids remain between the inorganic powders after firing in the cross section of the partition. Due to the presence of this void, when the structure in which the width of the partition wall is narrowed is adopted, the improvement of the strength of the partition wall against dropping, vibration, etc. is reduced. In addition, when the chipping or the like occurs due to insufficient strength of the partition walls, there is a case where an adverse effect on discharge characteristics or crosstalk due to local shape variation may occur. However, in the PDP according to the embodiment of the present invention described above, the occurrence of the above-described problems can be suppressed due to the presence of the third inorganic material.

  In addition, by using the third inorganic material, the surface roughness of the top, side, and bottom of the partition 12 is significantly improved as compared with the conventional partition. As described above, the third inorganic material has fluidity because the viscosity of the third inorganic material is significantly reduced before reaching the maximum firing temperature of the partition wall 12 as described above. Further, since the second inorganic component and the third inorganic component that are softened near the maximum firing temperature are glass components similar to each other, the wettability is good, and the third inorganic material is the second inorganic material. Easy to cover the surface. Thereby, the surface roughness of the partition wall 12 is reduced, and the surface area can be reduced. As a result, the amount of gas adsorbed can be reduced, so that the problem that the gas adhering to the partition wall adversely affects the discharge characteristics in the panel can be suppressed.

In the above description, the second and third inorganic materials become the partition walls 12 that are glass sintered bodies by firing. For example, a ZnO—B ₂ O ₃ —SiO ₂ -based mixture, PbO —B ₂ O ₃ —SiO ₂ type mixture, PbO—B ₂ O ₃ —SiO ₂ —Al ₂ O ₃ type mixture, PbO—ZnO—B ₂ O ₃ —SiO ₂ type mixture, Bi ₂ O ₃ — B ₂ O ₃ -SiO ₂ -based, etc. _{ZnO-Bi 2 O 3 -B 2} O 3 -SiO 2 based mixtures can be mentioned.

Here, the softening point temperature can be adjusted by changing the composition ratio of the main component (for example, PbO) contained in the material or the composition ratio of SiO ₂ . In general, when it is desired to lower the softening point, it is effective to increase the composition ratio of PbO and to decrease the composition ratio of SiO ₂ . For example, as a glass powder having a softening point of around 600 ° C., the total weight is 100% by weight, lead oxide (PbO) is 45% to 65% by weight, boron oxide (B ₂ O ₃ ) is 10% to 30% by weight, Silicon oxide (SiO ₂ ) 10 wt% to 30 wt%, calcium oxide (CaO) 1 wt% to 10 wt%, aluminum oxide (Al ₂ O ₃ ) 0 wt% to 3 wt% as additives. On the other hand, in order to lower the softening point by 50 ° C., it can be realized by increasing the weight percentage of PbO by 5 to 10% and decreasing the increased amount by another composition.

  Further, as shown in FIGS. 4A and 4B as a cross-sectional perspective view of a schematic configuration and a cross-sectional view of a schematic configuration (a phosphor layer is not shown), as a partition 12, a vertical direction 12c and a horizontal direction 12d It has a two-layer structure consisting of a lower layer 12f and an upper layer 12g with a cross-sectional shape having different heights and a portion having a different height as a boundary 12e, and at least one of these two layers is three or more types It is good also as what contains these inorganic materials. By adopting such a configuration, it is possible to optimize each of the two layers of the partition wall 12. That is, it is considered that the partition wall 12 is chipped by contacting the front plate 1, and the strength of the upper layer 12g of the partition wall 12 is considered to be very important. Therefore, the strength of the upper layer 12g of the partition wall 12 can be improved for the above-described reason by making the partition wall 12 have a two-layer structure of the upper layer 12g and the lower layer 12f and the upper layer 12g includes three or more kinds of inorganic materials. it can. In addition, due to the presence of the third inorganic material, the shape of the upper surface of the upper layer 12g can be made to have relatively few local protrusions, etc. Therefore, it is possible to prevent the occurrence of problems such as chipping of the partition wall 12.

  Further, for example, the upper layer 12g has an optimum composition system in contact with the front plate 1 as described above, and the lower layer 12f has a smoother surface in order to reduce gas adsorption, and voids inside the partition walls of the lower layer 12f. As a result, it is possible to use an inorganic material having a lower softening point than the upper layer 12g.

  Here, the structure of the partition is not limited to the above, and may be two or more layers, or may be a two-layer structure in a stripe shape or a cross-beam shape.

  Further, only one of the upper layer 12g and the lower layer 12f may include three or more kinds of inorganic materials.

  Further, the softening point of the third inorganic material having the lowest softening point is within a range of −50 ° C. to + 150 ° C. with respect to the softening point of the sealing frit which is a sealing member for sealing the PDP at the periphery thereof. It is preferable that Here, for example, when the softening point of the sealing frit is around 410 ° C., it is conceivable that the sealing is performed at around 460 ° C. That is, the aforementioned temperature range is ± 100 ° C. with the sealing temperature as the center. By setting it as such a temperature range, the viscosity of the 3rd inorganic material of a partition can be reduced moderately by baking at the time of PDP sealing, and the above-mentioned operation can fully be obtained, and with the front plate 1 The above-described effect that the contact state can be made satisfactory can be sufficiently obtained. The softening point of the third inorganic material is preferably equal to or lower than the sealing temperature, but if it is too low, it is not preferable because the glass itself is difficult to prepare. As the upper limit, when the softening point of the third inorganic material is 100 ° C. or more away from the sealing temperature, the viscosity cannot be sufficiently reduced, and the above-described functions and effects are sufficiently obtained. It may not be obtained.

  In addition, it is preferable that the three or more types of inorganic materials have at least two types of inorganic materials in the form of particles having different particle size distributions. That is, the softening temperature of the inorganic material is affected by the particle size distribution in addition to the softening point. For example, even if the softening point is the same, the smaller the particle size distribution, the faster the softening. This is presumably because the surface energy is reduced by making the particles finer. Therefore, the fluidity of the inorganic material with respect to firing can be changed by changing the particle size distribution in each inorganic material. From this viewpoint, the particle size distribution may be set so that the softening point of the third inorganic material is the lowest. Further, by making the particle size distribution of the third inorganic material smaller than the particle size distribution of the first and second inorganic materials, it becomes easy to enter between the particles of the first and second inorganic materials, and the voids are reduced. You can also get the effect.

  Further, the partition wall 12 has at least a two-layer structure, includes an inorganic component having at least three different particle size distributions, and the particle size distribution of at least one inorganic component in each layer is different in each layer. Is also preferable. In this case, by reducing the particle size distribution of the inorganic material serving as the filler, the surface-specific protrusions and shape changes can be reduced. Therefore, the first layer 12g of the upper layer 12g of the partition wall 12 in contact with the front plate 1 is used. It is preferable to reduce the particle size distribution of the filler which is an inorganic material.

  In the above description, the particle size distribution is a value of D50, and ranges from 0.1 to 20 μm. Within this range, for example, the D50 of the third component may be 2 μm or less, but is not limited thereto.

  Further, in the case of high definition, for the purpose of improving the discharge efficiency, there are cases where the partial pressure of xenon, for example, is 5% to 50% as the discharge gas. It is possible to obtain similarly.

  Of the three types of inorganic materials, the first inorganic material can be easily identified by analyzing the cross section with EDAX or the like after the back plate 2 is formed. In addition, the second and third inorganic materials can be easily distinguished if the compositions constituting the glass are different. Even when the same glass composition system is used, the fact that the softening point is changed means that, as described above, the weight percentage of the main component of the glass is significantly different. Therefore, by quantitative analysis, for example, PbO (or Pb) It can be determined if there are regions having different content ratios.

  As described above, according to the present invention, it is possible to provide a partition structure having sufficient strength and suppressed gas generation, and thus to provide a PDP capable of high efficiency and high image quality. It becomes possible.

1 is a cross-sectional perspective view showing a schematic configuration of a plasma display panel according to an embodiment of the present invention. The top view which shows schematic structure of the plasma display panel by one embodiment of this invention Sectional drawing which shows schematic structure of the partition of the conventional plasma display panel 1 is a cross-sectional perspective view showing a schematic configuration of a plasma display panel according to an embodiment of the present invention, and FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front plate 2 Back plate 4 Scan electrode 5 Sustain electrode 6 Display electrode 7 Dielectric layer 8 Protective layer 9 Substrate 10 Address electrode 11 Dielectric layer 12 Partition 13 Phosphor layer 14 Discharge gap

Claims (2)

Across the partition wall so as to form a discharge space provided with an opposed the front plate and the back plate, the partition wall is at least two-layered structure, both of the two layers comprises three or more kinds of inorganic materials, wherein In the two layers, the lower layer is formed using an inorganic material having a softening point lower than that of the upper layer, and the inorganic material having the lowest softening point among the three or more types of inorganic materials has a particle size distribution of other types of inorganic materials. A plasma display panel having a particle size smaller than the particle size distribution. The partition wall includes a in at different heights parallel crosses shaped vertical and horizontal directions, and a plasma display panel according to the two-layer structure der Ru claim 1, boundary different portions of heights.

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