JP2005063719A - Glass plate for display and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop glass for display having a high transmittance characteristic. <P>SOLUTION: The manufacturing method of a glass plate for display using low dielectric glass as a transparent dielectric layer is provided. The method includes at least a preheating process, a vacuum burning process, and a heating treatment process. The preheating process is made at an atmospheric temperature of 300-400°C and by a degree of vacuum of 1.3×10<SP>-4</SP>-1.3×10<SP>-8</SP>kPa. The vacuum burning process is made at an atmospheric temperature of 300-650°C and by a degree of vacuum of 1.3×10<SP>-4</SP>-1.3×10<SP>-8</SP>kPa. The heating treatment process is made under an atmosphere having oxygen at an atmospheric temperature of 500-650°C, and for a treatment time of 10 minutes-1 hour. Additionally, the glass plate for display is manufactured by the method using low-fusing-point glass containing, in weight %, SiO<SB>2</SB>1-25, B<SB>2</SB>O<SB>3</SB>10-36, PbO 18-70, ZnO 5-26, BaO 0-25, CuO 0.05-1, and MnO<SB>2</SB>0.05-1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a display substrate using a low dielectric glass as a transparent dielectric layer of a display substrate, and more particularly to a front panel of a plasma display panel using a high transmission type low dielectric glass.

  With the recent development of electronic components, many types of display panels such as plasma display panels, liquid crystal display panels, electroluminescence panels, fluorescent display panels, electrochromic display panels, light emitting diode display panels, and gas discharge display panels have been developed. Has been. Among them, plasma display panels are attracting attention as thin and large flat color display devices. In a plasma display panel, there are many cells between a front substrate and a back 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. This insulating material is preferably excellent in plasma durability and transparent. For this reason, dielectric glass is often used as an insulating material. However, the conventional dielectric glass has a significant problem that the visible light transmittance is less than 90% and sufficient visible light transmittance cannot be obtained.

Looking at the known technology, 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 90 μm or less in size and softening. The point is 480-620 ° C., expressed in weight%, PbO 0-80%, B ₂ O ₃ 0-25%, SiO ₂ 10-60%, MgO 0-15%, CaO 0-15 %, ZnO is 0 to 25%, Al ₂ O ₃ is 0 to 15% low melting point glass powder for electrode coating using a low melting point glass and plasma display device (for example, see Patent Document 1), PbO A plasma display material with a limited CuO content (see, for example, Patent Document 2) is also a plasma display material with a limited content of BaO + SrO + MgO in addition to PbO, B ₂ O ₃ , SiO ₂ , CaO. For example, see Patent Document 3), and further disclosed is a material for plasma display in which the content of BaO + CaO + Bi ₂ O ₃ , ZnO, B ₂ O ₃ , SiO ₂ , PbO, SnO ₂ is limited (see, for example, Patent Document 4). Has been.
Japanese Patent Laid-Open No. 2000-11903 JP 2001-52621 A JP 2001-80934 A JP 2001-48577 A

  The conventional display panel has a problem that the visible light transmittance of the front plate is low. In particular, in a plasma display panel, low visible light transmittance is a very big problem. If the visible light transmittance is low, the brightness of the light source must be increased, but this means that a large amount of light emission energy is required, and this is contrary to the recent social needs for saving resources and energy. become. The low visible light transmittance of plasma display panels is often attributed to dielectric materials (insulating materials), but it is difficult to cope with this high transmittance, and the visible light transmittance is 90% or higher. No dielectric material has been developed. Therefore, development of a dielectric material that solves the above-described problems, particularly the development of a front plate for a plasma display having an improved dielectric material is awaited.

  That is, the method disclosed in Japanese Patent Application Laid-Open No. 2000-119033 cannot disclose a front panel for a plasma display panel having a high transmittance characteristic. Furthermore, although the methods of Japanese Patent Application Laid-Open Nos. 2001-52621, 2001-80934, and 2001-48577 are considerably improved, the visible light transmittance tends to be low.

  The present invention is a method for producing a glass plate for display, which comprises at least a preliminary heating step, a vacuum firing step and a heat treatment step in the production of a display glass plate using low dielectric glass as a transparent dielectric layer of a display substrate.

  Moreover, a preheating process is a manufacturing method of said glass plate for a display performed at the atmospheric temperature of 300-400 degreeC.

Moreover, a vacuum baking process is the manufacturing method of said glass plate for a display performed by the range of the vacuum degree of 1.3 * 10 < ^-4 > -1.3 * 10 < ^-8 > kPa at the atmospheric temperature of 300-650 degreeC. .

  Moreover, a heat processing process is said manufacturing method of the glass plate for a display performed in the atmosphere which has oxygen, and the range of the atmospheric temperature of 500-650 degreeC, and the processing time of 10 minutes-1 hour.

  The temperature difference between the end temperature of the preheating process and the start temperature of the vacuum baking process, and the temperature difference between the end temperature of the vacuum baking process and the start temperature of the heat treatment process is within 50 ° C. is there.

  Furthermore, it is a glass plate for a display which uses the low melting point glass which is manufactured by the above method and has a visible light transmittance of 90% or more at a thickness of 30 μm.

Furthermore, the low-melting-point glass is composed of 1 to 25 SiO ₂ , 10 to 36 B ₂ O ₃ , 18 to 70 PbO, 5 to 26 ZnO, 0 to 25 BaO, and 0 CuO by weight%. 0.05 to 1, and the glass plate for display as described above, which is a low melting point glass containing 0.05 to 1 MnO ₂ .

  Furthermore, it is a front plate for a plasma display panel using the glass plate for display described above.

  Furthermore, the plasma display panel front plate has a visible light transmittance of 75% or more when the low-melting glass is used as a transparent dielectric layer.

  According to the present invention, it has been possible to obtain a glass plate for display that has been low in visible light transmission, particularly a front plate for plasma display, that has high visible light transmission.

  The present invention is a method for producing a glass plate for display, which comprises at least a preliminary heating step, a vacuum firing step and a heat treatment step in the production of a display glass plate using low dielectric glass as a transparent dielectric layer of a display substrate. The above preheating step, vacuum firing step and heat treatment step are all necessary steps and are indispensable. That is, the most important step in the present invention is a vacuum baking step, but a good effect cannot be produced without a preliminary heating step or a subsequent heat treatment step. Here, the preheating step means a step performed mainly for the purpose of de-binding and preventing breakage at the start of the vacuum firing step. Further, the heat treatment process has a feature that it is performed in an oxygen atmosphere.

  The preheating step is preferably performed at an ambient temperature of 300 to 400 ° C. If it is less than 300 ° C., debinding cannot be performed well, and if it exceeds 400 ° C., effective vacuum firing cannot be performed in the subsequent vacuum firing step. This is because preliminary conditions for performing vacuum firing, such as temperature conditions and management of volatile components, are affected.

Moreover, it is preferable that a vacuum baking process is performed in the range of the vacuum of 1.3 * 10 < ^-4 > kPa-1.3 * 10 < ^-8 > kPa at the atmospheric temperature of 300-650 degreeC. Further, from the viewpoint of prevention of destruction and efficiency, it is desirable that the vacuum firing process is performed at 300 to 450 ° C. at the start and 550 to 650 ° C. at the end. If the atmospheric temperature is less than 300 ° C., a lot of time is required in the vacuum firing process, and the firing process is not efficient. Further, when the binder removal is not sufficiently performed in the previous step, it is necessary to surely remove the organic substance as the binder component as soon as possible. However, this is not possible, and a problem occurs in ensuring transparency. On the other hand, if the ambient temperature exceeds 650 ° C., the fluidity of the dielectric glass becomes too high and the electrode components ITO and Ag are eroded. Furthermore, the diffusion of silver ions into the dielectric glass becomes intense and the problem of yellowing becomes significant. More preferably, it is the range of 360-600 degreeC.

Moreover, if the degree of vacuum is less than 1.3 × 10 ⁻⁴ kPa, the number of internal bubbles in the glass increases, and the visible light transmittance decreases. On the other hand, when the degree of vacuum exceeds 1.3 × 10 ⁻⁸ kPa, the thickness of the dielectric layer becomes thin, and a problem of insulation failure occurs when a panel is formed. Preferably, it is in the range of 1.3 × 10 ⁻⁵ kPa to 1.3 × 10 ⁻⁷ kPa.

  The heat treatment step is preferably performed in an atmosphere containing oxygen and in an atmosphere temperature of 500 to 650 ° C. and a treatment time of 10 minutes to 1 hour. This is related to the fact that the vacuum firing is completed at about 650 ° C. or less, and the sample is destroyed when the temperature is lower than 500 ° C. On the other hand, when the ambient temperature exceeds 650 ° C., the fluidity of the dielectric glass becomes too high, and the electrode components ITO and Ag are eroded. Furthermore, the diffusion of silver ions into the dielectric glass becomes intense and the problem of yellowing becomes significant. More preferably, it is 500-600 degreeC.

  The temperature difference between the end temperature of the preheating process and the start temperature of the vacuum baking process and the end temperature of the vacuum baking process and the start temperature of the heat treatment process are within 50 ° C. When the temperature difference exceeds 50 ° C., there is a problem that the glass sample is broken. Preferably, it is within 30 ° C.

  Furthermore, it is a glass plate for a display which uses the low melting point glass which is manufactured by the above method and has a visible light transmittance of 90% or more at a thickness of 30 μm. By manufacturing by the above method, a glass plate for display using a low melting point glass having a visible light transmittance of 90% or more at a thickness of 30 μm can be obtained. Here, the reason for setting the thickness to 30 μm is that the transmittance varies depending on the film thickness, and for example, it is based on a thickness of 30 μm that is often used in a plasma display panel. The higher the visible light transmittance at a thickness of 30 μm, the better. However, when it is lower than 90%, the luminous efficiency must be high, and there is a problem in terms of energy.

  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 plate for plasma display composed of the front glass plate 1, the transparent electrode 4, the bus electrode 5, the transparent dielectric 6 and the protective film 7 is important for each component. It is also necessary to look comprehensively.

Furthermore, the low melting point glass, a SiO ₂ 1 to 25 _weight%, B 2 _{O 3} and 10 to 36, 18 to 70 a PbO, a ZnO 5 to 26, 0 to 25 and BaO, and CuO 0. 05-1 is preferably a display glass is a low melting glass of MnO ₂ containing 0.05.

SiO ₂ is a glass forming component, which expands the vitrification range and contributes to glass stabilization. The SiO ₂ content is preferably 1 to 25% by weight. If the amount is less than 1% by weight, the glass stabilizing effect cannot be exhibited. If the amount exceeds 25% by weight, the glass viscosity increases, and it is difficult to remove bubbles during baking.

B ₂ O ₃ is introduced as a main component of glass formation similar to SiO ₂ , and the amount of B ₂ O ₃ introduced is in the range of 10 to 36% by weight. If it is less than 10% by weight, glass formation is unstable and devitrification and crystals are likely to occur. On the other hand, if it exceeds 36% by weight, the viscosity of the glass is lowered, and bubbles are aggregated during baking to reduce the visible light transmittance.

PbO is a component necessary for lowering the melting point of glass, that is, lowering the softening point temperature and imparting fluidity, and the amount of PbO introduced is in the range of 18 to 70% by weight. If it is less than 18% by weight, the effect cannot be sufficiently exerted, and bubble removal upon firing becomes insufficient. When it exceeds 70% by weight, the softening point becomes too low, the leaching and diffusion of the transparent electrode wire and the bus electrode wire component become remarkable, and the thermal expansion coefficient becomes excessive. Preferably, ZnO in the range of 19 to 61% by weight is introduced for imparting fluidity to the glass and adjusting the coefficient of thermal expansion, and the range is 5 to 26% by weight. If the amount is less than 5% by weight, the action cannot be exerted. If the amount exceeds 26% by weight, the glass becomes unstable and is easily crystallized.

  BaO is a component used for adjusting the high temperature viscosity and adjusting the expansion coefficient, and the introduction amount is in the range of 0 to 25% by weight. If it exceeds 25% by weight, the expansion coefficient becomes excessive, and it becomes incompatible with the substrate glass.

  CuO has an effect of mitigating the reaction between the silver electrode used as the bus electrode wire and the dielectric layer, and the diffusion of silver into the dielectric layer and the color development of silver colloid (yellowing). Introduced in the range of 1% by weight. If it is less than 0.05% by weight, the effect is not sufficiently exhibited, and yellow coloring (yellowing) occurs at the end of the electrode. If it exceeds 1% by weight, the glass is colored and the transparency is lowered, which is not preferable.

MnO ₂ has the effect of suppressing the silver colloid coloration (yellowing) due to the reaction between the silver electrode used as the bus electrode wire and the dielectric layer, and the diffusion of silver into the dielectric layer. Introduced in the range of 1% by weight. If it is less than 0.05% by weight, the action is not exhibited, and yellow coloring (yellowing) occurs at the end of the electrode. If it exceeds 1% by weight, the glass is colored and the transparency is lowered, which is not preferable.

  Furthermore, it is a front plate for a plasma display panel using the glass plate for display.

  Further, the plasma display panel front plate has a visible light transmittance of 75% or more when the low-melting glass is used as a transparent dielectric layer. A front plate for a plasma display having a visible light transmittance of less than 75% requires a large energy for light emission, and thus the apparatus becomes large, which causes a problem in terms of environment. More preferably, it is 80% or more.

  A glass plate for display comprising a glass substrate having a thickness of 2 to 4 mm and a visible light transmittance of 80% or more at a thickness of 3 mm and the above-described low-melting glass is also preferable. Since the visible light transmittance of the glass substrate varies greatly with the plate thickness, the visible light transmittance at 3 mm thickness is used as a reference. If the glass substrate is thinner than 2 mm, the practicality is poor in terms of strength and rigidity. On the other hand, when it exceeds 4 mm, it becomes too heavy as display glass. More preferably, it is 2.3-3 mm.

Furthermore, in the case of using a low melting point glass described above as a glass powder, in the range the average particle diameter _{D 50} less 0.5~3μm the grinding device, preferably 0.8～2.5Myuemu, more preferably 1. It is useful to adjust the powder size to 0 to 2.0 μm or less and a maximum particle size D _MAX of 20 μm or less. When the average particle diameter D ₅₀ is less than 0.5, together with the grinding efficiency is deteriorated, because the particle size is too small, the adsorption amount of such organic materials contained in the resin at the time of paste or a sheet is increased, the dielectric This is not preferable because the transparency of the layer is lowered. If the average particle diameter D ₅₀ is more than 3.0 [mu] m, when baking low melting glass at 600 ° C. or less, along with reducing the transparency of the inherent air bubbles in the glass is increased dielectric layer, the dielectric layer The surface roughness of the surface becomes worse, and the panel contacts with the partition wall or the like when the panel is formed. Furthermore, since the dielectric strength of the surface of the dielectric layer is deteriorated, incident light to the dielectric layer is scattered and the apparent brightness becomes a problem.

  Hereinafter, description will be made based on examples.

Fine silica sand as the SiO ₂ source, boric acid as the B ₂ O ₃ source, zinc white as the ZnO source, barium nitrate as the BaO source, lead oxide as the PbO source, copper oxide as the CuO source, and dioxide as the MnO ₂ source Manganese is used to prepare the desired low-melting glass composition, and then put into a platinum crucible and heated and melted in an electric heating furnace at 1100 to 1400 ° C. for 1 to 2 hours. The low melting glass shown in Example 1 (Sample No.) is obtained. Moreover, a commercially available 70 mm × 70 mm soda-lime glass plate having a thickness of 2.9 mm was prepared as the front plate glass.

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-described low melting point glass and heat-treated to obtain a transparent low dielectric layer. That is, the paste-like low-melting glass was applied using an applicator, dried at a temperature of about 100 ° C., and then preheated for debinding at 300 ° C. and finally 390 ° C. . Then, vacuum baking was started from 405 degreeC, and it heated up to 595 degreeC, maintaining the inside of a baking furnace at the vacuum degree of 1.3 * 10 < ^-5 > kPa. After vacuum firing for about 20 minutes, air was again sent into the firing furnace and fired at atmospheric pressure for 45 minutes to obtain a transparent dielectric layer. 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 for visible light transmittance at a wavelength of 550 nm using a spectrophotometer (U-4000 type: Hitachi, Ltd.), the visible light transmittance of this glass plate was about 85%.

  Since the visible light transmittance of the soda-lime glass plate with MgO was about 91% and the average thickness of the dielectric layer was 30 μm, the visible light transmittance of the 30 μm-thick low melting point glass is Estimated to be about 93%.

(Examples 2 to 5)
The following low melting point glasses having different glass compositions were used and examined by the same production method and measurement method as in Example 1. As a result, as shown in Table 1, the low-melting glass had a visible light transmittance of more than 90%, and the front plate had a visible light transmittance of more than 75%. In Examples 1 to 5, it was confirmed that there was no yellow coloration, and that D ₅₀ was 1.0 to 2.0 μm and the maximum particle size D _MAX was 20 μm or less.

(Comparative Examples 6 to 10)
As shown in Table 2, the production conditions were changed. In addition, the place which is not specified was performed according to Example 1. As a result, in Comparative Examples 6 and 10, the sample was damaged, and the visible light transmittance could not be measured. In all cases, the low melting point glass had a visible light transmittance of less than 90%, and the front plate had a visible light transmittance of less than 75%. Furthermore, in Comparative Example 9, there was a problem of insulation failure during panel formation.

  As described above, by using a transparent insulating low-melting glass having a visible light transmittance of 90% or more as a transparent dielectric layer of the front glass plate, a plasma with a high visible light transmittance is obtained. A front plate for display was obtained.

The softening point was the temperature at which the viscosity coefficient reached ^107.6 using a Littleton viscometer. Moreover, the thermal expansion coefficient was calculated | required from the amount of elongation at 30-350 degreeC when it heated up at 5 degree-C / min with the thermal dilatometer.

1 is a schematic view of a plasma display panel showing a configuration of the present invention 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 (9)

A method for producing a glass plate for display, comprising at least a preliminary heating step, a vacuum firing step and a heat treatment step in the production of a display glass plate using low dielectric glass as a transparent dielectric layer of a display substrate. The method for producing a glass plate for a display according to claim 1, wherein the preheating step is performed at an atmospheric temperature of 300 to 400 ° C. The vacuum firing step is performed at an atmospheric temperature of 300 to 650 ° C. and in a vacuum degree range of 1.3 × 10 ^{−4 to} 1.3 × 10 ⁻⁸ kPa. The manufacturing method of the glass plate for a display of description. The heat treatment step is performed in an atmosphere containing oxygen and in an atmosphere temperature of 500 to 650 ° C and a treatment time of 10 minutes to 1 hour. Manufacturing method of glass plate for display. 5. The temperature difference between the end temperature of the preheating process and the start temperature of the vacuum baking process, and the temperature difference between the end temperature of the vacuum baking process and the start temperature of the heat treatment process is within 50 ° C. 5. The manufacturing method of the glass plate for displays of crab. A glass plate for a display, comprising a low-melting glass produced by the method according to claim 1 and having a visible light transmittance of 90% or more at a thickness of 30 μm. The low-melting glass is 1 to 25 by weight, SiO ₂ is 1 to 25, B ₂ O ₃ is 10 to 36, PbO is 18 to 70, ZnO is 5 to 26, BaO is 0 to 25, CuO is 0.05 to 1 The glass plate for a display according to claim 6, which is a low-melting glass containing 0.05 to 1 MnO ₂ . A front plate for a plasma display panel, wherein the display glass plate according to claim 6 or 7 is used. 9. The plasma display panel according to claim 8, wherein a visible light transmittance of a front plate of the plasma display panel when the low melting point glass described in claim 7 is used as a transparent dielectric layer is 75% or more. Front plate.

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