JP2005353435A - Plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem, wherein in a reflecting layer formed of white pigment powder, impurity gas of moisture (H<SB>2</SB>O), carbon dioxide (CO<SB>2</SB>) or the like adsorbed to its surface is emitted by discharge, and the emitted impurity gas is adsorbed to a protective film or the like, whereby the discharge characteristics are degraded, that is to say, the discharge start voltage is raised and the sustaining voltage is made large as well. <P>SOLUTION: A second dielectric layer 56 is so structured as to contain a glass layer 70 incorporating bubbles 72 and a white pigment 74 in contact with the bubbles 72. Thereby, the reflectivity thereof is large and will not degrade. In addition, since the white pigment 74 contacts the bubbles 72 or is covered with the glass layer 70, emission of the impurity gas from its surface is restrained, even if the white pigment 74 adsorbs the impurity gas of H<SB>2</SB>O or the like, whereby the discharge characteristics will not be degraded. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

  The plasma display panel is a flat display that displays an image by exciting phosphors with ultraviolet rays generated by gas discharge. The plasma display panel is classified into a transmission type and a reflection type depending on how light is extracted from the phosphor layer that has emitted light. Since the transmissive type extracts light through the phosphor layer, a part of the visible light is absorbed and reflected by the phosphor layer, and the luminance is lowered. On the other hand, the reflection type can extract light directly from the front surface of the phosphor layer, and light directed toward the back surface is reflected by the phosphor layer and extracted, resulting in high brightness.

However, even in the case of such a reflection type plasma display panel, the reflection of the phosphor layer is not sufficient, and a configuration in which a reflection layer is provided inside the partition wall on the back side of the phosphor layer in order to further increase the luminance. It is disclosed. Here, as the reflective layer, a white glaze layer in which fine glass such as titanium oxide (TiO ₂ ) or alumina (Al ₂ O ₃ ) is dispersed is used which is mainly composed of lead glass having a low softening point.

One factor that determines the reflective performance of a reflective layer using such a white glaze layer is the difference in refractive index between the glass component and the dispersed powder. That is, the reflectance of the white glaze layer increases as the refractive index difference between the glass component and the dispersed powder increases. Although the refractive index of TiO ₂ is as large as about 2.6, the refractive index of the glass component is as large as about 1.8 and the difference in refractive index cannot be taken so much, so that the reflectance is small and the luminance is not greatly improved. Accordingly, a configuration has been proposed in which a white pigment layer in which fine powder white pigments such as TiO ₂ and Al ₂ O ₃ are filled with high density without using a glass component is used as the reflective layer (for example, Patent Document 1).
JP 10-74555 A

However, the white pigment as described above easily adsorbs moisture (H ₂ O) and carbon dioxide (CO ₂ ). Therefore, the reflective layer using the white pigment layer absorbs a large amount of H ₂ O and CO ₂ . It is in an adsorbed state. During the gas discharge, impure gases such as H ₂ O and CO ₂ adsorbed on the surface are released from the reflective layer. Then, the released impure gas is adsorbed by the protective film and the like, and as a result, the discharge characteristics are deteriorated, which causes a problem of an increase in sustain voltage due to an increase in discharge start voltage and an increase in power consumption resulting therefrom. There was a case.

  The present invention has been made to solve the above-described problems, and realizes a plasma display panel including a reflective layer that can suppress the generation of impure gas and can secure a necessary reflectance. With the goal.

  The present invention relates to a plasma display panel in which a front substrate on which display electrodes are formed, a rear substrate on which data electrodes and barrier ribs are formed are arranged to face each other so that the display electrodes and the data electrodes intersect with each other. A dielectric layer is provided so as to cover the dielectric layer, and the dielectric layer includes a glass layer containing bubbles and a white pigment in contact with the bubbles.

With such a configuration of the dielectric layer, the white pigment is covered with the bubbles and the glass layer. Therefore, even if the dielectric layer is exposed to discharge, moisture (H ₂ O) or carbon dioxide (CO ₂ ) ) And the like are suppressed, and the discharge characteristics are not deteriorated. Furthermore, since the white pigment having a large refractive index difference and the bubbles are in contact with each other, the reflectance is not greatly reduced.

  The present invention also relates to a plasma display panel in which a front substrate on which display electrodes are formed, a rear substrate on which data electrodes and barrier ribs are formed are arranged to face each other so that the display electrodes and the data electrodes intersect with each other. A reflective layer is provided on the side surface of the glass plate, and the reflective layer includes a glass layer containing bubbles and a white pigment in contact with the bubbles.

With such a reflective layer configuration, the white pigment is covered with bubbles and a glass layer, so that emission of impure gases such as H ₂ O and CO ₂ from the white pigment is suppressed even when ultraviolet rays are irradiated during discharge. The discharge characteristics are not deteriorated. Furthermore, since the white pigment having a large refractive index difference and the bubbles are in contact with each other, the reflectance is not greatly reduced.

The white pigment of the plasma display panel of the present invention may contain at least one of titanium oxide (TiO ₂ ), alumina (Al ₂ O ₃ ), and silica (SiO ₂ ). Since these white pigments have a high refractive index, the reflectance also increases.

  The glass layer of the plasma display panel of the present invention may be made of a glass material having a refractive index of 1.7 or less. When a material having a small refractive index of the glass layer is used as described above, the difference in refractive index from the white pigment increases and the reflectance also increases.

  The glass layer of the plasma display panel of the present invention may be made of a glass material having a dielectric constant of 8 or less. When a material having a low dielectric constant of the glass layer is used as described above, the capacitance between the data electrodes is reduced, leading to reduction of reactive power.

  The volume ratio of the glass layer constituting the dielectric layer or the reflective layer of the plasma display panel of the present invention to the bubbles and the white pigment is 40% or more and 80% or less for the glass layer, 5% or more and 50% for the bubbles. Hereinafter, the white pigment may be 10% or more and 50% or less.

  When the volume ratio of the glass layer, the bubbles, and the white pigment is increased, the ratio of the white pigment that comes into contact with the bubbles increases, the reflectance increases, and the white pigment is covered with the bubbles and the glass layer. Generation of gas is suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the plasma display panel provided with the reflection layer which can suppress generation | occurrence | production of impure gas and can ensure a required reflectance is realizable.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment)
FIG. 1 is a perspective view showing a main configuration of a plasma display panel for explaining a plasma display panel and a manufacturing method thereof according to an embodiment of the present invention. The front substrate 10 and the rear substrate 40 are arranged to face each other, and have a transparent and insulating front glass substrate 14 and a rear glass substrate 44 as base materials. On the front substrate 10, display electrodes 28 including scan electrodes 24 and sustain electrodes 26 arranged in parallel are arranged. In order to improve contrast between the display electrodes 28, a black pigment such as chromium (Cr) is mixed with glass frit to form a paste, patterned, and baked to form the light shielding layer 30. And while forming the 1st dielectric material layer 32 so that these may be covered, the protective layer 34 is further formed on this 1st dielectric material layer 32, and the process of manufacturing the front substrate 10 is completed.

Here, a predetermined number of display electrodes 28 are formed on the front substrate 10 with a certain pitch. Both the scanning electrode 24 and the sustain electrode 26 are composed of transparent electrodes 24a and 26a and bus electrodes 24b and 26b made of silver electrodes or the like and having a narrower width than the transparent electrodes 24a and 26a. Further, the first dielectric layer 32 is required to be formed so as to reliably cover the display electrode 28 after the display electrode 28 is formed. Here, the first dielectric layer 32 is formed by applying a dielectric paste with, for example, a die coater and drying it, followed by firing in a firing furnace. Examples of the dielectric paste material include so-called (PbO—) containing, for example, lead oxide (PbO), silicon oxide (SiO ₂ ), boron oxide (B ₂ O ₃ ), zinc oxide (ZnO), barium oxide (BaO), and the like. A low-melting glass paste having a (SiO ₂ —B ₂ O ₃ —ZnO—BaO) glass composition can be used. Alternatively, a glass paste containing at least one of lead oxide (PbO), bismuth oxide (Bi ₂ O ₃ ), and phosphorus oxide (PO ₄ ) as a main component can be used.

  The protective layer 34 is provided to prevent the first dielectric layer 32 from being sputtered by plasma discharge, and is required to be a material excellent in sputtering resistance. For this reason, magnesium oxide (MgO) is often used.

  On the other hand, on the rear substrate 40, data electrodes 54 arranged in parallel for writing image data as an electrode group are arranged and formed in a direction orthogonal to the display electrodes 28 of the front substrate 10. Then, after the second dielectric layer 56 is formed so as to cover the data electrodes 54, a plurality of partition walls 58 are formed in parallel with the data electrodes 54 at substantially the center between the data electrodes 54. Then, the phosphor layer 60 that emits red, green, and blue light is formed between the partition walls 58 including the side surfaces of the partition walls 58, and the process of manufacturing the back substrate 40 is completed.

  Thereafter, when the front substrate 10 and the back substrate 40 are overlapped and joined, a discharge space surrounded by the barrier ribs 58, the protective layer 34, and the phosphor layer 60 is generated. Then, the gas in the discharge space is exhausted, and a gas mixed with neon (Ne), xenon (Xe) or the like is sealed at a pressure of about 66.5 kPa, and the assembly process is completed, and a color image is displayed. A plasma display panel (hereinafter, the plasma display panel having this configuration is referred to as panel A) is obtained.

  Here, the volume ratio of the glass layer, bubbles, and white pigment constituting the second dielectric layer 56 is 40% to 80% for the glass layer, 5% to 50% for the bubbles, and 10% for the white pigment. It may be determined so that it is 50% or less and the total does not exceed 100%. When the volume ratio of the glass layer, the bubbles, and the white pigment is increased, the ratio of the white pigment that comes into contact with the bubbles increases, the reflectance increases, and the white pigment is covered with the bubbles and the glass layer. Generation of gas is suppressed. If the glass layer is less than 40%, the white pigment cannot be sufficiently covered. On the other hand, when the white pigment exceeds 50%, it becomes difficult to mix the materials for forming a paste.

  The dielectric paste as the material of the second dielectric layer 56 is prepared by mixing a glass material, a filler, an organic binder, and an organic solvent. As the glass material, a low melting point glass material having a refractive index of 1.7 or less is preferable. With such a glass material having a low refractive index, a difference in refractive index from the white pigment can be increased, and the reflectance can be increased. A low melting point glass material having a dielectric constant of 8 or less is preferable. With such a glass material having a low dielectric constant, the capacitance between the data electrodes 54 can be reduced, and the reactive power can be reduced.

Specific examples of the glass material described above include ZnO—B ₂ O ₃ —SiO ₂ (refractive index: Nd = 1.57, dielectric constant: ε = 7.2), ZnO—B ₂ O ₃ —. Al ₂ O ₃ (Nd = 1.62, ε = 7.4), ZnO—B ₂ O ₃ —SiO ₂ —Al ₂ O ₃ (Nd = 1.60, dielectric constant: ε = 7.3) It is done. Further, these glass materials may contain an alkali metal oxide. By including the alkali metal oxide, the softening temperature of the glass material can be lowered.

The filler includes at least one selected from titanium oxide (TiO ₂ ), alumina (Al ₂ O ₃ ), and silica (SiO ₂ ), which are white pigments. These white pigments have a high refractive index and are necessary for increasing the reflectance.

  The organic binder is preferably ethyl cellulose or an acrylic resin, and the organic solvent is preferably a high boiling point such as α-terpineol or butyl carbitol acetate.

  Then, after applying this dielectric paste in a coating process using a coating method such as a die coater or a screen printing method, it is dried in a drying process using a warm air drying furnace, a far-infrared drying furnace, etc. to evaporate the organic solvent. Let

  Next, the organic binder is decomposed in the baking step of the baking furnace, and the glass material is softened and melted to form a glass film having a thickness of about 15 μm. Here, it is necessary to bake in a temperature range from the glass softening temperature of the glass material to a temperature lower than the temperature at which bubbles in the glass material finish defoaming. Here, as a factor for generating bubbles, the through holes due to the gaps between the glass particles are closed at the softening temperature of the glass material.

FIG. 2 is a cross-sectional view showing the configuration of the second dielectric layer 56 according to the embodiment of the present invention. The second dielectric layer 56 includes a glass layer 70 containing bubbles 72 and a white pigment 74 in contact with the bubbles 72. Thus, since the white pigment 74 is in contact with the bubbles 72 or is covered with the glass layer 70, even if the white pigment 74 adsorbs an impure gas such as H ₂ O, the impure gas from the surface thereof. Release is suppressed. Further, the reflectance of light incident on a medium having a different refractive index increases as the refractive index difference between the media increases, so that the white pigment 74 is in contact with the glass layer 70 having a small refractive index difference. The reflectance is larger when the bubble 72 is in contact with a larger refractive index difference. Therefore, it is necessary to form the second dielectric layer 56 so as to include the bubbles 72, and the firing temperature range is less than the temperature at which the bubbles of the glass powder finish defoaming from the glass softening temperature at which bubbles are generated. It is.

The specific firing temperature is glass softening when the glass material is ZnO—B ₂ O ₃ —SiO ₂ , ZnO—B ₂ O ₃ —Al ₂ O ₃ , or ZnO—B ₂ O ₃ —SiO ₂ —Al ₂ O _3. At a temperature of about 500 ° C., bubbles having a diameter of 1 μm to 2 μm start to be generated. Then, at about 600 ° C., which is 100 ° C. higher, the bubbles are completely degassed. The bubble diameter is more preferably 3 μm to 7 μm from the viewpoint of improving the reflection performance, and a firing temperature of 530 ° C. or higher and 570 ° C. or lower forming the bubble diameter is a more preferable temperature range.

  Next, FIG. 3 is a cross-sectional view of the back substrate of the plasma display panel according to another embodiment of the present invention. In this configuration, a reflective layer 76 is provided between the partition walls 58, and a phosphor layer 60 is provided on the reflective layer 76. The plasma display panel having such a configuration is referred to as a panel B. The reflective layer 76 is made of the same material as that of the second dielectric layer 56 in the configuration of the panel A, and is applied by screen printing, and then baked at the same baking temperature as that of the second dielectric layer 56. did. The back substrate 40 has the same structure as that of the panel A. On the back glass substrate 44, a data electrode 54 and a second dielectric layer 57 are formed so as to cover the data electrode 54, and a partition wall 58 is provided. . However, the second dielectric layer 57 was formed by the same material and firing method as the first dielectric layer 32 in the configuration of the panel A.

In the present invention, the second dielectric layer 56 in the configuration of the panel A and the reflective layer 76 in the configuration of the panel B are 50% glass layer, 30% bubbles, and 20% white pigment layer of TiO ₂ by volume. Formed with. The second dielectric layer 56 in the configuration of the panel A and the reflective layer 76 in the panel B are formed by 50% of the glass layer and 50% of the white pigment layer of TiO ₂ by volume ratio, and Comparative Example 1 To do. Further, a comparative layer _{2 in} which the reflective layer 76 in the configuration of the panel B is formed of only TiO ₂ powder is referred to as Comparative Example 2.

  Table 1 shows the reflectance and sustain voltage in the present invention, Comparative Example 1 and Comparative Example 2 in the configurations of Panel A and Panel B. The reflectance is measured in a wavelength range of 360 nm to 740 nm, and a value of 550 nm is shown as a representative value. For the measurement, a spectrocolorimeter (manufactured by Minolta Co., Ltd .: CM-3600d) was used. Further, the sustain voltage is shown as a relative value based on the case of Comparative Example 1.

As can be seen from Table 1, when the configuration of the panel A, that is, the second dielectric layer 56 is the configuration of the present invention, the reflectance is improved by 10% compared with the comparative example 1 which is the conventional configuration, and the sustain voltage is also increased. does not change. Further, if the configuration of the panel B, that is, the reflective layer 76 is the configuration of the present invention, the reflectance is improved by 9% compared to the comparative example 1, and the sustain voltage is not changed. Furthermore, compared with Comparative Example 2 formed only in powder white pigment conventional TiO _2, although the reflectivity is reduced 2%, the sustain voltage is reduced to 1 to 1.2, the discharge characteristics are improved .

This is because the second dielectric layer or the reflective layer includes a glass layer containing bubbles and a white pigment such as TiO ₂ that comes into contact with the bubbles, thereby suppressing impure gas emission from the surface of the white pigment, This is because the discharge characteristics are improved. Further, since the white pigment is in contact with the air bubbles, a large difference in refractive index can be obtained, and the reflectance is not greatly reduced as compared with the case of using only the white pigment.

  In the embodiment of the present invention, the second dielectric layer or the reflective layer is configured to include a glass layer containing bubbles and a white pigment that contacts the bubbles. Both layers may have the above structure. Further, the barrier ribs may be formed of the same material and firing method as the dielectric layer and the reflective layer containing the white pigment, and the reflectance may be further increased by contacting the white pigment with the bubbles.

  According to the plasma display panel of the present invention, since the emission of impure gas can be suppressed without greatly reducing the reflectance, the discharge characteristics such as the sustain voltage are not lowered, and the dielectric of the back plate of the plasma display panel Useful for layers and reflective layers.

The perspective view which shows the main structures of the plasma display panel in embodiment of this invention Sectional drawing which shows the structure of the 2nd dielectric material layer of embodiment of this invention Sectional drawing of the back substrate of the plasma display panel of other embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Front substrate 14 Front glass substrate 24 Scan electrode 24a, 26a Transparent electrode 24b, 26b Bus electrode 26 Sustain electrode 28 Display electrode 30 Light-shielding layer 32 First dielectric layer 34 Protective layer 40 Back substrate 44 Back glass substrate 54 Data electrode 56 57 Second dielectric layer 58 Bulkhead 60 Phosphor layer 70 Glass layer 72 Bubbles 74 White pigment 76 Reflective layer

Claims (6)

A plasma display panel having a front substrate on which display electrodes are formed, a rear substrate on which data electrodes and barrier ribs are formed facing each other so that the display electrodes and the data electrodes intersect with each other, and covering the data electrodes A plasma display panel, wherein a dielectric layer is provided, the dielectric layer including a glass layer containing bubbles and a white pigment in contact with the bubbles. A plasma display panel in which a front substrate on which display electrodes are formed, a back substrate on which data electrodes and barrier ribs are formed are arranged to face each other so that the display electrodes and the data electrodes intersect with each other, and at least a side surface of the barrier ribs A plasma display panel, wherein a reflective layer is provided, and the reflective layer includes a glass layer containing bubbles and a white pigment in contact with the bubbles. _3. The plasma display panel according to claim 1, wherein the white pigment includes at least one of titanium oxide (TiO ₂ ), alumina (Al ₂ O ₃ ), and silica (SiO ₂ ). The plasma display panel according to any one of claims 1 to 3, wherein the glass layer is made of a glass material having a refractive index of 1.7 or less. The plasma display panel according to any one of claims 1 to 3, wherein the glass layer is made of a glass material having a dielectric constant of 8 or less. The volume ratio of the glass layer, bubbles, and white pigment is that the glass layer is 40% or more and 80% or less, the bubbles are 5% or more and 50% or less, and the white pigment is 10% or more and 50% or less. 6. The plasma display panel according to claim 4, wherein the plasma display panel is characterized.

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