JP4079904B2 - Low dielectric materials for display panels containing organic-inorganic hybrid glassy materials - Google Patents

Description

  The present invention relates to a low dielectric material for a display panel containing an organic-inorganic hybrid glassy substance.

  With the recent development of electronic parts, particularly display panels, development of materials having physical properties that have not been required has been desired. For example, it is a material having a high visible light transmittance, a low softening temperature characteristic, and a low dielectric constant. Once such materials are developed, plasma display panels, liquid crystal display panels, electroluminescence panels, fluorescent display panels, electrochromic display panels, light emitting diode display panels, gas discharge display panels, etc. There is a high possibility that it can be applied to display panels. For example, it is expected to be applied to a plasma display panel, which is particularly attracting attention as a thin and large flat color display device.

  The plasma display panel has many cells between a front substrate and a rear substrate used as a display surface, and an image is formed by performing plasma discharge in the cells. This cell is partitioned by partition walls, and an electrode is formed for each pixel unit in order to control the display state of each pixel forming an image. An electrode for discharging plasma is formed on the front glass plate of the plasma display panel, and thin linear silver is often used as the electrode. A highly transparent insulating material is disposed around the electrode. The insulating material is preferably a so-called low dielectric material having plasma durability and a low dielectric constant. Furthermore, since transparency is required, low dielectric glass having a low softening temperature characteristic is often used as an insulating material. Similarly, glass substrates used other than plasma display panels are preferably excellent in plasma durability, transparent and have a low dielectric constant.

  On the other hand, as a method for producing a low dielectric glass having a low softening temperature characteristic, a sol-gel method, a liquid phase reaction method, an acid anhydride base reaction method, and the like are considered. In the sol-gel method, metal alkoxide is hydrolyzed and polycondensed, and heat treatment is performed at a temperature exceeding 500 ° C. (see, for example, Non-Patent Document 1), usually 700 to 1600 ° C., thereby obtaining a thin-film low dielectric glass. be able to. The sol-gel method is said to be able to obtain a bulk material, but it is porous due to the decomposition and combustion of organic substances such as alcohol introduced during the preparation of the raw material solution, or evaporative emission during the heating process of decomposition gas or water of organic substances. Therefore, a low dielectric glass having a low softening temperature characteristic has not been produced by the sol-gel method.

  The liquid phase reaction method has a low yield due to the low yield, as well as the use of hydrofluoric acid in the reaction system and the limited thin film synthesis. It is almost impossible to produce a bulk-like low dielectric glass having the above.

  The anhydride-base reaction method is a technique developed in recent years, and it is possible to produce an organic-inorganic hybrid glass having a low softening temperature characteristic (for example, see Non-Patent Document 2), but it is still under development and can be produced. Glass is also limited, and at the present time, it has not been developed even to satisfy the characteristics capable of obtaining sufficient visible light transmittance.

  Therefore, the production of glass having many low softening temperature characteristics has been carried out not by a low temperature synthesis method but by a melting method. For this reason, the glass composition is limited for the convenience of melting the glass raw material, and the type of the low dielectric glass that can be substantially produced is extremely limited.

  As described above, in the conventional method, a low dielectric glass capable of meeting the recent demand for electronic components has not been developed. That is, high visible light transmittance, softening point of less than 500 ° C. without containing lead (temperature at which Log η becomes 7.6), and dielectric constant of 10 or less are satisfied at the same time. Furthermore, chemical durability and other requirements There has never been a material that satisfies the physical properties, and its development is strongly desired.

In view of the known technology, as the transparent material exhibiting low softening temperature characteristics, for example, the 10% diameter under the integrated sieve is 1.0 μm or less, the 50% diameter is 0.3 to 5.0 μm, and the 90% diameter under the integrated sieve is 10%. Having a particle size of 0.0 μm or less, a softening point of 480 to 620 ° C., expressed in weight%, PbO of 0 to 80%, B ₂ O ₃ of 0 to 25%, SiO ₂ of 10 to 60%, MgO but 0-15%, CaO is from 0 to 15%, ZnO is 0~25%, _Al 2 _{O 3} is covering electrodes for the low melting point glass powder and a plasma display device using a low melting glass consisting of 0-15% (e.g. In addition, PbO and CuO (see Patent Document 2) are also limited to PbO, B ₂ O ₃ , SiO ₂ , CaO, and BaO + SrO + MgO. Limit amount The specified plasma display material (for example, refer to Patent Document 3) is a plasma display material in which the content of BaO + CaO + Bi ₂ O ₃ , ZnO, B ₂ O ₃ , SiO ₂ , PbO, SnO ₂ is limited (for example, Patent Document 4) is disclosed.

Japanese Patent Laid-Open No. 2000-11903 JP 2001-52621 A JP 2001-80934 A JP 2001-48577 A Kamiya, K., Sakuhana, K., Tashiro, K., Journal of Ceramic Industry Association, 618-618, 84 (1976). Masahide Takahashi, Haruki Niida, Toshinobu Yokoo, New Glass, 8-14, 17 (2002).

  Conventional low dielectric materials cannot satisfy high visible light transmittance, softening temperature of less than 500 ° C. without containing lead, and dielectric constant of 10 or less at the same time. Therefore, development of a dielectric material that solves the above-described problems, and further development of a display substrate or display panel having an improved dielectric material are awaited.

  A low dielectric material satisfying the above can be obtained by the methods disclosed in Japanese Unexamined Patent Application Publication Nos. 2000-1119039, 2001-52621, 2001-80934, and 2001-48577. I can't get it.

  The present invention relates to a low dielectric material for a display panel, wherein the material is a metal alkoxide as a starting material, a mixing step using the metal alkoxide as a raw material, water, an acid catalyst and an alcohol, a heating reaction step, a melting step A low-dielectric material for a display panel, comprising an organic-inorganic hybrid glassy material produced through a process and an aging process and having meltability.

  In addition, in the above-mentioned low dielectric material for a display panel, the dielectric constant of the organic-inorganic hybrid glassy substance is 2.5 or more and 9 or less.

  Further, the low dielectric material for a display panel described above, wherein the visible light transmittance at a thickness of 30 μm is 90% or more.

The display panel glass plate is characterized by using the above-mentioned low dielectric material for a display panel.

  According to the present invention, it is possible to obtain a low dielectric material for a display panel that has high visible light transmittance, does not contain lead, has a softening temperature of less than 500 ° C., and a dielectric constant of 10 or less.

  The present invention is a low dielectric material for a display panel containing an organic-inorganic hybrid glassy substance. There are many types of low dielectric materials for display panels, and they are used in many places. A plasma display panel will be described as an example. As shown in FIG. 1, the plasma display panel is sandwiched between a front glass plate 1 and a back glass plate 2, and the front glass plate 1 and the back glass plate 2 are sealed with a sealing material 3. There are a front glass plate 1, a transparent electrode 4, a bus electrode 5, a transparent dielectric 6 and a protective film 7 at the front of the panel, and a back glass plate 2, an address electrode 8, a white dielectric 9, and a phosphor on the back. 10 and a partition wall 11. The ultraviolet rays 12 become visible light 13 due to the action of the phosphor 10. Among these, the front glass plate 1, the rear glass plate 2, the sealing material 3, the transparent dielectric 6, the protective film 7, and the partition wall 11 can be used. That is, it is characterized in that it can be used as a substrate or a low dielectric material mixed with other materials. In order to use as a substrate, the heat treatment temperature for forming a display panel needs to be 600 ° C. or lower, more preferably 500 ° C. or lower.

  The present invention relates to a low dielectric material for a display panel, wherein the material is a metal alkoxide as a starting material, and a heating reaction step after a mixing step using the metal alkoxide as a raw material, water, an acid catalyst and an alcohol. A low dielectric material for a display panel, which is produced through a melting step and an aging step and contains an organic-inorganic hybrid glassy substance having a melting property. This organic-inorganic hybrid glassy material is that the product obtained from the oxide precursor as the raw material of the sol-gel method has a melting property, and further, it can eliminate the gelation step that required 1-3 days. It has characteristics.

  The metal alkoxide used as a raw material is an alkoxysilane substituted with an organic substituent. The organic substituent is a phenyl group, a methyl group, an ethyl group, a propyl group (n-, i-), a butyl group (n-, i-, t-), pentyl group, hexyl group, octyl group, decyl group, dodecyl group, octadecyl group, mercaptomethyl group, mercaptopropyl group, 3,3,3-trifluoropropyl group, 3-trifluoroacetoxypropyl group, vinyl It is preferably selected from a group, a benzyl group, a styryl group, and the like, and a metal alkoxide composed of a methoxy group, an ethoxy group, a propoxy group (n-, i-) or the like as an alkoxyl group. These are extremely useful raw materials for producing an organic-inorganic hybrid glassy material, particularly a transparent material having a low softness at room temperature or lower. Metal alkoxides other than those described above may be used. In addition, metal acetylacetonate, metal carboxylate, metal nitrate, metal hydroxide, metal halide, and the like can be produced as long as they are used in the sol-gel method, but may contain a phenyl group. Further preferred.

  In the mixing step, it is preferable to use a catalyst. With respect to these catalysts, there is no problem with the alkali catalyst and acid catalyst used in the conventional sol-gel method, but ammonia is more preferable as the alkali catalyst, and hydrochloric acid and acetic acid are more preferable as the acid catalyst.

  Typical alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 2-butanol, 1.1-dimethyl-1-ethanol and the like. However, it is not limited to these.

It is preferable to have a heating reaction step before entering the melting step, that is, between the starting material mixing step and the melting step by heating. This heating reaction step is preferably performed at a temperature of 40 ° C. or higher and 100 ° C. or lower. Outside this temperature range, a metal unit having an organic functional group R in its structure, for example, a silicon unit represented by (R _n SiO _{(4-n) / 2} ) (selected from n = 1, 2, 3), Further, in detail, a phenyl group metal unit (Ph _n SiO _{(4-n) / 2} ), a methyl group metal unit (Me _n SiO _{(4-n) / 2} ), an ethyl group metal unit (Et _n SiO _{(4-n) / 2} ), butyl group metal units (Bt _n SiO _{(4-n) / 2} ) (n = 1 to 3) and the like cannot be appropriately contained, so that the glass can be melted organic Obtaining an inorganic hybrid glassy material becomes extremely difficult.

  The organic functional group R is typically an alkyl group or an aryl group. The alkyl group may be linear, branched or cyclic. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group (n-, i-), a butyl group (n-, i-, t-), a pentyl group, a hexyl group (carbon number: 1 to 20). Particularly preferred are methyl and ethyl groups. Furthermore, examples of the aryl group include a phenyl group, a pyridyl group, a tolyl group, and a xylyl group, and a phenyl group is particularly preferable. Of course, the organic functional group is not limited to the above-described alkyl group or aryl group.

  The melting step by heating is preferably performed at a temperature of 40 ° C. or higher and 500 ° C. or lower. At temperatures lower than 40 ° C., it cannot be melted substantially. Further, when the temperature exceeds 500 ° C., the organic group bonded to the metal element forming the network burns, so that a desired organic-inorganic hybrid glassy material cannot be obtained, and it becomes opaque due to crushing or generation of bubbles. Or Desirably, it is 100 degreeC or more and 300 degrees C or less.

In the aging step, the treatment is performed at a temperature of 30 ° C. or higher and 400 ° C. or lower. At a temperature lower than 30 ° C., it cannot be aged substantially. When it exceeds 400 ° C., it may be thermally decomposed, and it becomes difficult to obtain a stable glassy substance. The effect of the aging temperature becomes extremely small at a temperature lower than the melting lower limit temperature. Generally, the lower limit of melting temperature to the lower limit of melting temperature (+ 150 ° C.) is desirable. Furthermore, the time required for aging is 5 minutes or more. The aging time varies depending on the processing amount, processing temperature, and allowable residual amount of reactive hydroxyl group (—OH), but generally it is extremely difficult to reach a satisfactory level in less than 5 minutes. Moreover, since productivity falls in a long time, it is 10 minutes or more and less than 1 week desirably. In addition, in the case of aging, 2 of the 1st ageing | curing | ripening performed at the temperature of 40 to 230 degreeC and the pressure of 1.5 * 10 < ^-5 > kPa or less and the 2nd ageing | curing | ripening performed at 70 to 350 degreeC under atmospheric pressure. It is also effective to divide into two steps.

  A stable organic-inorganic hybrid glassy material can be obtained through the melting step and the aging step. Since the conventional sol-gel method does not have the melting step, it naturally has no subsequent aging step, but also has a characteristic of passing through a gel body. Thus, it has different properties from the conventional organic-inorganic hybrid glassy material.

  The upper limit temperature of the heating reaction step is 100 ° C. or lower when an alcohol having a boiling point exceeding 100 ° C., for example, 1-butanol having a boiling point of 118 ° C. is used, but it is desirable to consider the boiling point of alcohol having a boiling point of 100 ° C. or lower. For example, when ethanol is used, the boiling point tends to be better at 80 ° C. or lower. This is presumably because when the boiling point is exceeded, the alcohol rapidly evaporates, so that it is difficult to achieve a uniform reaction from the amount of alcohol and changes in state.

  Since the time required for this heat treatment is about 30 minutes to 5 hours, it is greatly different from the treatment time by the conventional sol-gel method, which takes 1 to 3 days for gelation. In addition, after this heating reaction process, you may enter into a melting process immediately, and may enter into a melting process after cooling once.

  In addition, it is preferable that the softening temperature of this organic inorganic hybrid glassy substance is 80 degreeC or more and 400 degrees C or less. This is because the organic inorganic hybrid glassy material obtained has a low chemical stability at a temperature below 80 ° C., and often has no meltability at temperatures above 400 ° C. More preferably, it is 100 degreeC or more and 380 degrees C or less, More preferably, it is 100 degreeC or more and 350 degrees C or less. Here, the softening temperature of the organic-inorganic hybrid glassy substance can be determined from TMA measurement in which the temperature is increased at 10 ° C./min. That is, the shrinkage is measured under the above conditions, and the change start temperature of the shrinkage is defined as the softening temperature. This softening temperature may be considered to be substantially equal to the softening point (the temperature at which Log η becomes 7.6).

The dielectric constant of the organic-inorganic hybrid glassy substance is preferably 2.5 or more and 9 or less. If the dielectric constant of the organic-inorganic hybrid glassy material is less than 2.5, the strength cannot be maintained, so that it is difficult to use it for a display panel. On the other hand, when the dielectric constant of the organic-inorganic hybrid glassy material exceeds 9, various problems arise because it is dielectric. More preferably, it is 3-8, More preferably, it is 4-7. Here, the dielectric constant refers to the dielectric constant at 10 ⁶ Hz.

  Moreover, it is preferable that the visible light transmittance | permeability in 30 micrometers thickness of an organic inorganic hybrid glassy substance is 90% or more. When the visible light transmittance at 30 μm thickness of the organic-inorganic hybrid glassy material is less than 90%, the visible light transmittance in the case of a display panel is poor, resulting in a large light source, which consumes much energy than before. It will be necessary.

Furthermore, a display panel glass plate characterized by using the above-mentioned low dielectric material for display panels is preferable. By using such a display glass plate, an energy saving display front plate can be obtained. Obtainable.
Hereinafter, description will be made based on examples.

As a starting material, a mixed system of metal alkoxide phenyltriethoxysilane (PhSi (OEt) ₃ ) of about 10 ml and diethoxydiphenylsilane (Ph ₂ Si (OEt) ₂ ) of about 2 ml was used, and the molar ratio was 8: 2. . In a container, about 45 ml of water (molar ratio to phenyltriethoxysilane is 50), about 30 ml of ethanol (molar ratio to phenyltriethoxysilane is 10), and acetic acid as a catalyst to phenyltriethoxysilane and diethoxydiphenylsilane. About 0.5 ml (molar ratio to phenyltriethoxysilane was 0.01) was added, and after heating at 60 ° C. for 3 hours as a heating reaction step, the temperature was raised to 150 ° C. and melted for 1 hour. After melting and aging at 200 ° C. for 5 hours, the mixture was cooled to room temperature to obtain a transparent material having a thickness of about 3 mm.

The starting point of the softening behavior was determined from the change in shrinkage in the TMA measurement with the temperature raised at 10 ° C./min. The starting temperature was taken as the softening temperature, and the softening temperature of this substance was 108 ° C. The TMA curve for this material is shown in FIG. Further, it was confirmed that silicon unit R _n SiO _{(4-n) / 2} (R: organic functional group, n: 1 to 3) was present in a magnetic resonance measuring apparatus CMX-400 type manufactured by JEOL. In consideration of having an irregular network structure, the transparent material obtained this time is a material having an organic-inorganic hybrid glass structure, that is, an organic-inorganic hybrid glassy material.

The dielectric constant of this organic-inorganic hybrid glassy material was measured and found to be 4.5. This measurement is a result of 10 ⁶ Hz at 20 ° C. using a dielectric constant measuring device SI1255 type manufactured by Toyo Technica. Moreover, when the visible light transmittance of wavelength 300-800 nm was measured for this glass plate using the spectrophotometer U-4000 type made from Hitachi, the visible light transmittance in wavelength 550nm was about 86%. Therefore, the visible light transmittance at a thickness of 30 μm was estimated to be 97%.

Next, a soda-lime glass plate having a thickness of 2.9 mm and a thickness of 70 mm × 70 mm, which is commercially available as a front plate glass, was prepared. On the soda-lime glass plate, silver was printed as an electrode with a width of 63 μm and a depth of about 4 μm. Further, the periphery thereof was sealed with the above-mentioned organic-inorganic hybrid glassy substance, and heat-treated to obtain a transparent low dielectric layer. That is, an organic-inorganic hybrid glassy substance is mixed with an organic solvent such as acetone to form a paste at room temperature, and then applied using an applicator and dried at a temperature of about 100 ° C. While maintaining a vacuum of ⁻⁵ kPa, heat treatment was performed at 180 ° C. for 30 minutes. Furthermore, the transparent low dielectric material layer was obtained by baking for 1 hour at 250 degreeC under atmospheric pressure. Furthermore, the protective film of MgO was also provided, and the glass plate of the same structure as the front plate for plasma displays was obtained. When this glass plate was measured with a spectrophotometer, the visible light transmittance at a wavelength of 550 nm of this glass plate was about 85%. Note that the thickness of the organic-inorganic hybrid glassy material after coating was about 30 μm. The glass plate thus obtained was examined with the same specifications as the plasma display. As a result, the electric power charge was reduced by about 10% compared to the conventional type.

(Example 2)
An organic-inorganic hybrid glassy material similar to that obtained in Example 1 was used as a glass plate of 70 mm × 70 mm and a thickness of 3.0 mm. Next, silver was printed as an electrode with a width of 63 μm and a depth of about 4 μm, and the periphery thereof was sealed with a newly produced organic-inorganic hybrid glassy material, followed by heat treatment to obtain a transparent low dielectric layer. That is, using the meltability of the newly produced organic-inorganic hybrid glassy material, it was melted at a temperature of about 150 ° C. and then heat-treated at 180 ° C. for 30 minutes. Furthermore, it heated up to 250 degreeC and baked at atmospheric pressure for 1 hour, and the transparent dielectric material layer was obtained. Furthermore, the protective film of MgO was also provided, and the glass plate of the same structure as the front plate for plasma displays was obtained. When this glass plate was measured with a spectrophotometer, the visible light transmittance at a wavelength of 550 nm of this glass plate was about 87%. Note that the thickness of the organic-inorganic hybrid glassy material after coating was about 30 μm. The glass plate thus obtained was examined with the same specifications as the plasma display, and as a result, it was possible to achieve a reduction of about 12% in power charges compared to the conventional type.

(Comparative Example 1)
Use boric acid as the B ₂ O ₃ source, zinc white as the ZnO source, barium nitrate as the BaO source, and red lead as the PbO source. In an electric heating furnace, it is heated and melted at 1100 to 1400 ° C. for 1 to 2 hours to obtain a glass having about 45% B ₂ O ₃ , about 30% ZnO, about 1% BaO and about 24% PbO. Obtained. This glass was applied onto a soda-lime glass plate in the same manner as in the example to obtain a glass plate having the same structure as the front plate for plasma display. When this glass plate was measured with a spectrophotometer, the visible light transmittance of this glass plate was about 68%. The thickness of the low-melting glass after coating was about 30 μm, and the visible light transmittance of this glass was about 75%.

  Materials for sealing and covering display components such as PDP, optical information communication device materials such as optical switches and optical couplers, optical equipment materials such as LED chips, optical functional (non-linear) optical materials, It can be used in fields where low-melting glass is used, such as adhesive materials, and fields where organic materials such as epoxy are used.

It is the schematic of the panel for plasma displays shown in order to demonstrate the example of utilization of this invention. The TMA curve shown in Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front glass plate 2 Back glass plate 3 Sealing material 4 Transparent electrode 5 Bus electrode 6 Transparent dielectric 7 Protective film 8 Address electrode 9 White dielectric 10 Phosphor 11 Bulkhead 12 Ultraviolet 13 Visible light

Claims (4)

  In a low dielectric material for a display panel, the material is a metal alkoxide as a starting material, and after the mixing step with the metal alkoxide as a raw material and water, an acid catalyst and an alcohol, a heating reaction step, a melting step and an aging step A low dielectric material for a display panel, comprising an organic-inorganic hybrid glassy material produced through the process and having a melting property.   2. The low dielectric material for a display panel according to claim 1, wherein the organic-inorganic hybrid glassy substance has a dielectric constant of 2.5 or more and 9 or less.   The low dielectric material for display panels according to claim 1 or 2, wherein the visible light transmittance at a thickness of 30 µm is 90% or more.   A glass plate for a display panel, wherein the low dielectric material for a display panel according to any one of claims 1 to 3 is used.