KR100715968B1 - Non-Pb Borate glass composition with low melting point for plasma display panel - Google Patents

Abstract

The present invention relates to a lead-free low melting borate glass composition that can be used as a lead-free transparent dielectric glass composition for low-melting point displays used in plasma display panels.

The above object of the present invention is a plasma display panel for a composition comprising 10 to 30 mol%, 30 to 45 mol% ZnO and 5 to 20 mol% SiO ₂ 15 to 30 mol% B ₂ O ₃ , MgO and at least one of CaO In the lead-free low melting point borate glass composition, the composition has a technical feature in that the particle size size (d ₅₀ ) of the composition is composed of a lead-free low melting point borate glass composition for a plasma display panel having a particle size (d ₅₀ ) of less than or equal to 3.5 µm and more than 1.8 µm.

Therefore, the lead-free low melting point composition for the plasma display panel of the present invention can be used in materials requiring dielectric glass composition and other glass frits, and does not contain lead to prevent environmental pollution due to soil and water pollution. This has the effect of realizing a plasma display panel with high transmittance.

Lead Free, PDP, Display, Frit, Dielectric

Description

Non-Pb Borate glass composition with low melting point for plasma display panel

1 is a structural cross-sectional view of a PDP.

The present invention relates to a lead-free low-melting borate glass composition for a plasma display panel, more specifically, 15 to 30 mol% of B ₂ O ₃ , 10 to 30 mol%, comprising at least one or more of MgO and CaO, 30 to 45 mol% ZnO And a lead-free low melting borate glass composition for a plasma display panel comprising 5 to 20 mol% of SiO ₂ , wherein the particle size size (d ₅₀ ) of the composition is 3.5 μm or less and more than 1.8 μm or less than 1.8 μm. It relates to a borate glass composition.

Plasma Display Panels (PDPs) are used to display an image including characters or graphics by emitting phosphors by ultraviolet rays of 147 nm generated when a He + Xe or Ne + Xe gas is discharged. Such a PDP is not only thin and easy to enlarge, but also greatly improved in quality due to recent technology development.

Referring to FIG. 1, the PDP structure has an alternating current driving method including a lower glass substrate 12 on which an address electrode 11 is mounted and an upper glass substrate 14 on which a sustain electrode pair 13 is mounted. On the lower glass substrate on which the address electrode is mounted, a partition wall 16 dividing the dielectric thick film 15 and the discharge cells is formed. Phosphors are applied to the surfaces of the dielectric thick film and the partition walls. The phosphor emits light by ultraviolet rays generated during plasma discharge, thereby causing visible light to be generated. The dielectric layer 17 and the passivation layer 18 are sequentially formed on the upper glass substrate on which the sustain electrode pairs are mounted. The dielectric layer accumulates wall charges during the plasma discharge, and the protective layer protects the pair of sustain electrodes and the dielectric layer from sputtering of gas ions during the plasma discharge and increases the emission efficiency of the secondary electrons. The discharge cells of the PDP are filled with a mixed gas of He + Xe or Ne + Xe.

However, the glass composition for transparent dielectric materials used in the conventional plasma display panel has a low firing temperature, a linear expansion coefficient similar to that of the substrate, and PbO, B ₂ O ₃ and SiO ₂ having suitable dielectric constant characteristics in accordance with the thermal characteristics of the front and rear glass substrates. It has as a main component. The lead-free composition comparable to the PbO system has not been developed yet.

PbO-based glass compositions currently used as commercial transparent dielectrics for PDPs contain large amounts of PbO components that are harmful to humans and seriously affect environmental pollution. Therefore, a considerable amount of the glass is discarded during the manufacturing process. If a chemical reaction occurs with the problem of causing environmental pollution by soil and water pollution. In addition, in the case of a composition containing a large amount of conventional PbO, when made into a large area in the final product may act as a significant burden on the weight. In addition, Bi ₂ O ₃ glass, which is used as a lead-free low melting glass alternative, or BaO-based glass among alkaline earth oxides, also contains heavy metals classified as poisons. Inappropriate compositions are used.

According to Japanese Patent Laid-Open No. 2000-226231, ZnO is 20 to 45% by weight, B ₂ O ₃ is 20 to 34% by weight, SiO ₂ is 20 to 45% by weight, R ₂ O (K ₂ O, Na ₂ O and Li ₂ O) is 4 to 12% by weight, RO (sum of BaO and CaO) is 0 to 3% by weight, NaF is 0.5 to 8% by weight lead-free glass composition is introduced. In addition, U.S. Patent No. 6,417,123 has 20 to 45 wt% ZnO, 15 to 45 wt% BaO, 15 to 35 wt% B ₂ O ₃ , 3 to 15 wt% SiO ₂ , and PbO Introducing a glass composition of 0 to 24.5% by weight. All of the glass compositions provide glass compositions for use in PDP transparent dielectrics and partition wall forming agents. However, the glass composition of the Japanese Laid-Open Patent contains an alkali-based component of R ₂ O (K ₂ O, Na ₂ O, Li ₂ O), so that the reaction with the electrode is likely to occur, and the glass composition of the US patent is reduced. Although the amount is still small, the use of PbO-based components still raises the problem of not meeting the purpose of lead-free low melting glass.

Accordingly, the present invention is to solve the problems of the prior art as described above, by using a composition containing no PbO, Bi ₂ O ₃ and BaO at all lead-free low melting point for plasma display panel that can solve the environmental pollution problem It is an object to provide a borate glass composition.

Another object of the present invention is to provide a lead-free low melting borate glass composition for a plasma display panel (PDP) having a low firing temperature, strong water resistance, suitable linear expansion coefficient characteristics, and high transmittance.

The above object of the present invention is a plasma display panel for a composition comprising 10 to 30 mol%, 30 to 45 mol% ZnO and 5 to 20 mol% SiO ₂ 15 to 30 mol% B ₂ O ₃ , MgO and at least one of CaO In lead-free low melting borate glass compositions, the particle size size (d ₅₀ ) of the composition is achieved by a lead-free low melting point borate glass composition for plasma display panels having a particle size size (d ₅₀ ) of less than or equal to 3.5 µm and less than 1.8 µm.

The present invention relates to a lead-free low-melting borate glass composition for plasma display panels that does not contain heavy metals, in particular PbO and Bi ₂ O ₃ , and has a high transmittance of 80% or more.

Details of the above object and technical configuration of the present invention and the effects thereof according to the present invention will be more clearly understood by the following detailed description with reference to a table showing preferred embodiments of the present invention.

First, the thermal and chemical properties of each component of the B ₂ O ₃ -RO (composition comprising at least one of MgO and CaO) -ZnO system shown in Table 1 were mainly investigated.

1. Implementation method

The glass powder according to the present invention is a mixed batch of each raw material compound to the composition of the composition and then put into a platinum crucible or alumina crucible and melted for 60 minutes at 1300 ℃ to prepare a powder sample and a bulk specimen. The powder is milled using a mill grinder and dried after wet grinding. The particle size can be adjusted according to the milling time and the powder size is about d ₅₀ = 1.8㎛ when wet for about 3 hours. The transition point, the softening point, the coefficient of linear expansion, the water resistance, etc. were measured and shown in Table 2 below. The measurement method for each characteristic is shown below.

Lead-free low melting glass powder is mixed with an organic vehicle and made into a suitable paste form. In this case, the organic vehicle used generally uses a resin solvent solution, cellulose resin and acrylic resin as the resin, 3MMB or α-thepron as a solvent, dispersant, leveling agent, Precipitation inhibitor etc. can be mix | blended suitably. The paste may be uniformly dispersed using a three roll mill, a film is formed by screen printing, tape casting, or the like, followed by a drying process to obtain a desired dielectric glass layer through a firing process.

a) Transition point (Tg): measured by DTA (Differential Thermal Analysis) up to 1100 ℃ at a temperature increase rate of 10 ℃ / min.

b) Softening point (Ts): Measured at a rate of 25 ° C./min using a viscometer. The specimen size was measured after grinding by molding to 3mm × 3mm × 2mm.

c) Linear expansion coefficient (CTE): measured at a temperature of 5 ℃ / min using a thermal mechanical analyzer (TMA). Specimen size was prepared by molding 5mm × 5mm × 5mm.

d) Water resistance measurement: The prepared mass glass was placed in distilled water at 90 ° C. for 72 hours and then taken out to measure the change in weight.

e) Dielectric constant: An electrode having a diameter of 18 mm was formed on a dielectric film layer obtained by baking a paste on a stainless steel sheet on which an oxide film was formed, and a silver (Ag) paste was formed, and a dielectric constant of 1 MHz was measured using an impedance.

f) Transmittance: The powder-coated glass film shows a transmittance value measured at 550λ (µm) as an integrating sphere transmittance using an infrared-UV-visible spectrometer.

2. Changes in physical properties due to changes in composition

a) B ₂ O ₃ is a glass forming oxide which is an essential component for constituting glass, and is selected in the range of 15 to 30 mol% in order to obtain stable glass, and accordingly, the softening point and dielectric constant of the glass can be moderately reduced. If the amount is 30 mol% or more, a high softening point is formed and the water resistance is lowered, so it can be seen that addition of more than this content is not preferable. On the other hand, vitrification may be difficult at 15 mo1% or less.

b) RO can act as a glass modifier to lower the glass transition point and softening temperature, increase the coefficient of linear expansion and improve the withstand voltage. The composition of the RO is selected from the range of 10 to 30 mol% and is not preferable because it shows a significant increase in the coefficient of linear expansion when added more than 30 mol%, and also has high thermal properties and difficult glass formation. On the other hand, in 10 mol% or less, there exists a tendency for water resistance and durability to fall.

c) ZnO is effective in stabilizing the glass in the composition according to the present invention, and when the amount is 30 mol% or less, a suitable softening point cannot be obtained, and when it is 45 mol% or more, crystals are formed, which adversely affects the transmittance. Is not preferred.

d) SiO ₂ is a glass former that stabilizes the glass and increases water resistance and withstand voltage. If it exceeds 20 mol%, the softening point tends to be high.

e) Al ₂ O ₃ is a glass former, which stabilizes the glass in the range of 10 mol% or less, prevents powder phase, increases durability, and improves strength in partitions. The most suitable range is 0 to 5 mol% and there is a fear that vitrification becomes difficult when it exceeds 10 mol%.

f) P ₂ O ₅ is a glass former, which stabilizes the glass in the range of 10 mol% or less, and can be expected to complement the water resistance and thermal properties.

g) SnO is not an essential component, but when added in an amount of 10 mol% or less, the effect of improving water resistance and deteriorating thermal properties can be expected.

Table 2 shows the results of measuring the thermal and chemical properties of Examples 1 to 5 and Comparative Examples 6 to 7 of the present invention. Examples 1 to 5 exhibit good firing with firing at 600 ° C. or lower. However, Comparative Examples 6 to 7 did not show good firing at 600 ° C. or lower by increasing the softening point as the content of B ₂ O ₃ exceeded 30 mol% and the SiO ₂ content exceeded 20 mol%. The addition of SnO showed the effect of reducing the thermal properties and improving the water resistance.

As shown in Table 3, the effect on the permeability according to the particle size is shown that when d ₅₀ = 3.7㎛ contains a small amount of granules and relatively large bubble content according to the average particle size Could. As such, the finer the particle size, d ₅₀ = 2.5 μm d ₅₀ = 1.8 μm, the smaller the amount of inclusions, resulting in a higher transmittance of 80% or more. As a result, it was found that the particle size greatly influences the transmittance.

Therefore, the lead-free low melting borate glass composition for a plasma display panel of the present invention is a lead-free glass composition comprising B ₂ O ₃ , RO, ZnO and SiO ₂ , Al ₂ O ₃ , P ₂ O ₅ and SnO as additives. As a result, it is possible to solve the environmental pollution problem and to manufacture a dielectric glass layer for a plasma display panel having a low firing temperature, high water resistance, an effective coefficient of linear expansion, and a high transmittance.

Claims (4)

B ₂ O ₃ 15-30 mol%; 10 to 30 mol% of a composition comprising at least one of MgO and CaO; ZnO 30 to 45 mol%; SiO ₂ 5-20 mol%; And 1 to 10 mol% of at least one of P ₂ O ₅ and SnO, The particle size size (d ₅₀ ) of the composition is not less than 2.7㎛ 3.5㎛ Lead free low melting borate glass compositions for plasma display panels. B ₂ O ₃ 15-30 mol%; 10 to 30 mol% of a composition comprising at least one of MgO and CaO; ZnO 30 to 45 mol%; SiO ₂ 5-20 mol%; And 1 to 10 mol% of at least one of P ₂ O ₅ and SnO, The particle size size (d ₅₀ ) of the composition is more than 1.8 ㎛ less than 2.7 ㎛ Lead free low melting borate glass compositions for plasma display panels. B ₂ O ₃ 15-30 mol%; 10 to 30 mol% of a composition comprising at least one of MgO and CaO; ZnO 30 to 45 mol%; SiO ₂ 5-20 mol%; And 1 to 10 mol% of at least one of P ₂ O ₅ and SnO, The particle size (d ₅₀ ) of the composition is less than 1.8 ㎛ Lead free low melting borate glass compositions for plasma display panels. delete

Images