KR20090025857A - Pb-free colored dielectric glass composition for pdp - Google Patents

Abstract

A glass composition of free lead coloring dielectric for PDP is provided to be capable of sintering at 530~580°C without adding alkali component in order to lower a softening point. A glass composition of free lead coloring dielectric for PDP includes Bi2O3 20~60 weight%, B2O3 5~30 weight%, SiO2 0.1~20 weight%, Al2O3 0.1~20 weight%, BaO 5~30 weight%, ZnO 10~40 weight% and a coloring oxide or more 0.001~5 weight% selected from a group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Nd and Ce. The glass composition has light transmission more than 60% at a reference wavelength 550nm. The glass composition additionally oxide or more of 0.1~10 weight% selected from a group consisting of P2O5, MgO, CaO, SrO.

Description

Pb-free colored dielectric glass composition for PDP

The present invention relates to a glass composition of a colored dielectric for a plasma display panel (hereinafter referred to as PDP), 20 to 60% by weight of Bi ₂ O ₃ , 5 to 30% by weight of B ₂ O ₃ , 0.1 to 20% by weight of SiO ₂ , 0.1 to 10 wt% of Al ₂ O ₃ , 5 to 30 wt% of BaO, 10 to 40 wt% of ZnO, or 0.1 to 10 oxides each selected from the group consisting of P ₂ O ₅ , MgO, CaO and SrO It comprises by weight, consisting of 0.001 to 5% by weight of at least one or more colored oxides selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Nd, Ce.

The glass composition of the present invention relates to a colored dielectric film for a plasma display panel that improves contrast by exhibiting selective transmittance characteristics in a specific wavelength range in the visible light region and relieves eye fatigue. Thermally, optically, and electrically stable, the glass transition temperature (Tg) is 430-500 ° C., and low-temperature firing of 530-580 ° C. is possible.

PDP has a wide wide viewing angle, full color and fast response speed, and has been attracting attention as one of the next-generation displays because it is thin and has advantages of being larger than 40 inches. PDP puts Ne + Ar, Ne + Xe, etc. gas between the front glass and the back glass and the glass enclosed by the partition therebetween, and applies a voltage to the anode and the cathode to emit neon light to generate visible light. It is one of the flat panel image display apparatuses in which an image is transmitted to the outside by transmitting the light. In the PDP, the transparent dielectric not only enables the discharge to be maintained at a small driving voltage during gas discharge but also plays an important role in improving luminous efficiency. To this end, the requirements for transparent dielectrics should be at least 80% light transmittance, dielectric constants in the range 8 to 15, withstand voltages above 1.1 KV, and thermal expansion coefficients similar to those of glass substrates (60 to 90X10) to prevent thermal stresses between the adhesives. ^-7 / ℃), firing should be possible between 530 ~ 600 ℃.

Conventional transparent dielectrics include PbO-SiO ₂ -B ₂ O ₃ and PbO-B ₂ O ₃ based glass compositions whose main components are PbO, a very harmful substance to human body and environment. SiO ₂ -P ₂ O ₅ -ZnO-BaO system, SiO ₂ -B ₂ O ₃ -ZnO-BaO system and the like have been studied. However, in the lead-free glass composition, alkali metal oxides such as Li ₂ O, Na ₂ O, and K ₂ O are added to lower the softening point of the glass, and since alkali metal ions have very high mobility in glass, When the transparent dielectric is fired, ion exchange with adjacent Ag electrodes occurs, causing yellowing, which lowers the brightness of the panel.

An object of the present invention is environmentally friendly, which does not contain PbO in the existing transparent dielectric material, and can be fired at 530 to 580 ° C. without adding an alkali component such as Li ₂ O, Na ₂ O, K ₂ O to lower the softening point. In addition, at least one colorant oxide is added to the glass composition to provide a glass composition of a lead-free colored dielectric for PDP having a light transmittance of at least 60% or more in the visible region depending on the colorant.

The present invention is selected from the group consisting of Bi ₂ O ₃ , B ₂ O ₃ , SiO ₂ , Al ₂ O ₃ , BaO, ZnO and Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Nd, Ce It is characterized by consisting of at least one or more colored oxides.

The present invention also includes a group consisting of Bi ₂ O _3, B ₂ O ₃ , BaO, ZnO, Al ₂ O ₃ , SiO ₂ and Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Nd, Ce It includes at least one or more colored oxides selected from, and further comprises at least one oxide selected from the group consisting of P ₂ O ₅ , MgO, CaO and SrO, Li ₂ O, Na ₂ O, K ₂ O and the like It features a glass composition of a lead-free colored dielectric for PDP that can achieve light transmission properties without containing alkali metal oxides.

The glass composition of the lead-free colored dielectric for PDP according to the present invention is environmentally friendly and harmless to the human body because it does not contain lead oxide (PbO), and it is thermally and electrically stable and has a low softening point, which enables low-temperature firing at 530 to 600 ° C. In addition, it exhibits selective transmittance characteristics in specific wavelength ranges depending on the colorant in the visible region, and also has the characteristics of colored underplate and complementary colors, which can be useful for the manufacture of PDP colored dielectrics that improve contrast and relieve eye fatigue. have.

20 to 60% by weight of Bi ₂ O ₃ , 5 to 30% by weight of B ₂ O ₃ , 0.1 to 20% by weight of SiO _2, 0.1 to 20% by weight of Al ₂ O ₃ , 5 to 30% by weight of BaO, ZnO 10 40 wt% and 0.001-5 wt% of at least one or more colored oxides selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Nd, and Ce.

The present invention also includes a group consisting of Bi ₂ O _3, B ₂ O ₃ , BaO, ZnO, Al ₂ O ₃ , SiO ₂ and Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Nd, Ce At least one oxide selected from the group consisting of at least one oxide selected from the group consisting of P ₂ O ₅ , MgO, CaO and SrO, further comprising 0.1 to 10% by weight, respectively, Li ₂ O, Na ₂ Provided is a glass composition of a lead-free colored dielectric for PDP capable of achieving light transmission properties without containing alkali metal oxides such as O and K ₂ O.

Hereinafter, each component constituting the glass composition according to the present invention will be described.

Bi ₂ O ₃ acts as a glass former when added with B ₂ O ₃ or SiO ₂ , lowers the softening temperature (Ts), and increases the coefficient of thermal expansion (CTE) and dielectric constant. However, as the content of Bi ₂ O _{3 increases} , the color of the mother glass becomes dark brown and the coefficient of thermal expansion (CTE) increases, causing thermal stress with the surrounding materials. Preferably, it is more preferable that it contains 30-50 weight%.

B ₂ O ₃ is an essential oxide that is involved in glass formation, and its content should preferably be 5 to 30% by weight, more preferably 10 to 30% by weight. A B ₂ O ₃ content of less than 5% makes vitrification difficult. If the content exceeds 30%, the resulting glass may cause phase separation, increasing the softening temperature (Ts) of the glass.

BaO, as a glass formula, lowers the glass transition temperature (Tg) and softening temperature (Ts) of the glass composition, and serves to increase the dielectric constant and coefficient of thermal expansion (CTE). The content of BaO is preferably 5 to 30% by weight, more preferably 10 to 30% by weight. If the BaO content is less than 5% by weight, the softening temperature (Ts) is high, and if it exceeds 30% by weight, the coefficient of thermal expansion (CTE) becomes very large.

ZnO is a free formula, a component that lowers the softening temperature (Ts), dielectric constant, and coefficient of thermal expansion (CTE), the content is preferably 10 to 40% by weight, more preferably 20 to 40% by weight. When the content of ZnO is less than 10% by weight, the softening temperature (Ts) is high, the baking is difficult at 530 ~ 580 ℃, if the content exceeds 40% by weight, it causes the discoloration of the electrode when firing.

SiO ₂ is a glass forming component, and acts to stabilize the glass chemically and optically, while the glass transition temperature (Tg) and softening temperature (Ts) is very high. Therefore, since the softening temperature (Ts) is very high, if the content of SiO ₂ exceeds 20% by weight, the content of SiO ₂ is preferably to be 0.1 to 20% by weight, preferably comprising 1 to 10% by weight.

Al ₂ O ₃ is a glass stabilizer that increases the softening temperature (Ts) and lowers the coefficient of thermal expansion (CTE). If the content of Al ₂ O ₃ exceeds 20% by weight, the softening temperature (Ts) is very high, so the content of Al ₂ O ₃ is preferably included in an amount of 0.1 to 20% by weight, preferably 1 to 15% by weight. .

P ₂ O ₅ is a glass-forming agent that increases the softening temperature (Ts), the coefficient of thermal expansion (CTE), and lowers the dielectric constant. Therefore, when the content of P ₂ O ₅ exceeds 10% by weight, since the softening temperature (Ts) and the coefficient of thermal expansion (CTE) are high, it is preferable to include 0.1 to 10% by weight, preferably 0.1 to 5% by weight. .

MgO, CaO and SrO are free formulas, slightly lower the softening temperature (Ts), slightly increase the coefficient of thermal expansion (CTE), MgO, CaO, SrO in order of effect. However, since the specific gravity of MgO and CaO is small, and SrO is added in a large amount, at least one oxide of MgO, CaO or SrO may be 0.1 to 10% by weight, respectively. Is preferably contained in 0.1 to 5% by weight.

Oxides of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Nd and Ce are used as additives for glass and control the color of the glass. When the content is 5% by weight or more, the light transmittance may be reduced and glass stability may be lowered due to excessive coloring. Therefore, the oxide may be included in an amount of 0.001 to 5% by weight, preferably 0.01 to 2% by weight, respectively.

Therefore, the glass composition of the lead-free colored dielectric for PDP of the present invention is 30 to 50% by weight of Bi ₂ O ₃ , 10 to 30% by weight of B ₂ O _3, 10 to 30% by weight of BaO, 20 to 40% by weight of ZnO, SiO ₂ 1-10% by weight, Al ₂ O ₃ 1-15% by weight, 0.1-5% by weight of at least one oxide selected from the group consisting of P ₂ O ₅ , MgO, CaO, SrO, Ti, V, More preferably, the composition contains 0.01 to 2% by weight of at least one or more colored oxides selected from the group consisting of Cr, Mn, Fe, Co, Ni, Cu, Nd, and Ce.

The above components may be mixed in an amount within the above range to prepare a glass composition of a lead-free colored dielectric for PDP of the present invention, and the glass composition having such a composition is melted at a high temperature of 1000-1500 ° C. and then quenched and pulverized dry. A glass powder can be obtained by doing this. The glass powder may have an average particle diameter of 2 to 3 μm, and the glass powder may be mixed with a commonly used vehicle and coated on a substrate in a paste state, followed by drying and firing to produce a desired lead-free colored dielectric for PDP. It can manufacture.

The coefficient of thermal expansion in the present invention is preferably 60 ~ 90X10 ^-7 / ℃ similar to the existing glass substrate, it is possible to bake between 530 ~ 600 ℃, the dielectric constant is 8 to 15 is suitable.

Hereinafter, based on the Example, the characteristic of the glass composition for PDP colored dielectrics which concerns on this invention is demonstrated in detail. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

Examples 1-5

The glass compositions for PDP colored dielectrics were prepared by mixing the components in the respective compositions shown in Table 1 below. The prepared glass composition was melted in an electric furnace at a temperature of 1250 ° C. and then quenched dry using twin rolls. The cullet obtained by quenching was pulverized by a dry mill to prepare a glass powder having an average particle diameter of 2.5 μm. Average particle size was measured using a particle size analyzer (Mastersizer 2000, Malvern, UK). 3-roll milling by mixing 70% by weight of the prepared glass powder with 30% by weight of a vehicle (10.78% by weight of ethyl cellulose, 28.05% by weight of dibutyl phthalate, 20.37% by weight of terpineol, 40.80% by weight of butylcarbitol acetate) A paste was prepared by defoaming, and the paste was coated on a glass substrate to a thickness of 100 to 150 μm, dried, and baked at a temperature of 560 to 580 ° C. to form a PDP colored dielectric layer.

In Table 1, the coefficient of thermal expansion (CTE) was measured at a heating rate of 10 ° C./min using a thermal analyzer (TMA: TMA-50, Shimadzu, Japan), and the coefficient of thermal expansion was measured from the slope in the range of 50 to 350 ° C. .

The glass transition temperature (Tg) and softening temperature (Ts) were measured in a range of up to 600 ° C at a heating rate of 10 ° C / min using a thermal analyzer (DTA: DTA-50, Shimadzu, Japan).

The dielectric constant of the sintered compact was measured at 1 MHz using an impedance analyzer (HP4192A, USA). The specimens were prepared by SiC (# 200, # 800, # 1200, # 2000) abrasive paper, and then polished the sintered body and then coated with Ag paste on both sides to form electrodes and measured at room temperature.

       The transmittance of the fired film was measured by using a spectrophotometer (U-350, Japan) of Hitachi, Ltd., and the transmittance of light having a reference wavelength of 550 nm was set to 100% without a sample.

The dielectric layer exhibited a transmittance of 60% or more when measuring the transmittance of light having a reference wavelength of 550 nm due to the influence of one or more colorants, did not cause yellowing, and exhibited high withstand voltage characteristics of 2 KV or more. The human eye has high sensitivity for light with a wavelength of 500 nm to 600 nm, but has low sensitivity in the wavelength band where short wavelength blue light belongs, so that the light transmittance of long wavelength and short wavelength of 550 nm is increased to improve the problem of low luminance of conventional PDP. In addition, it provided a colored dielectric for PDP having a total light transmittance of 60% or more.

FIG. 1 is a light transmittance curve of a fired film having a thickness after firing of Example 3 having a thickness of 40 μm or more. From the drawing, the light transmittance of the long wavelength band is increased, and the light transmittance of the 550 nm wavelength band is increased from 500 nm to 600 nm. It can be seen that the light transmittance is 60% or more.

Comparative example

YFT-340 (PbO 42.5 wt%, SiO ₂ 8.6 wt%, B ₂ O ₃ 31.4 wt%, BaO 17.1 wt%, CuO 0.4 wt%) for PDP transparent dielectrics containing lead oxide Thus, a PDP transparent dielectric layer was formed in the same manner as in the above embodiment. Glass powders prepared from commercial glass compositions had a glass transition temperature of 484 ° C., a thermal expansion coefficient of 77.5 × 10 ⁻⁷ / ° C., and a dielectric constant of 11 to 12, and a light transmittance of 78 to 80% at a reference wavelength of 550 nm. The transmittance and withstand voltage characteristics of 1.8 KV were shown, and no yellowing phenomenon was observed.

1 is a light transmittance curve in a visible region of a colored glass substrate and a colored dielectric

Claims (8)

20 to 60 wt% Bi ₂ O ₃ , 5 to 30 wt% B ₂ O ₃ , 0.1 to 20 wt% SiO _2, 0.1 to 20 wt% Al ₂ O ₃ , 5 to 30 wt% BaO, 10 to 40 wt% ZnO % And 0.001 to 5% by weight of at least one or more colored oxides selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Nd and Ce, respectively. Glass compositions of lead-free colored dielectrics. The method of claim 1, The glass composition is a lead-free colored dielectric glass composition for PDP, characterized in that having a light transmittance of at least 60% or more at a reference wavelength of 550nm. The method of claim 1, The glass composition further comprises 0.1 to 10% by weight of at least one oxide selected from the group consisting of P ₂ O ₅ , MgO, CaO, and SrO, respectively, in the glass composition. The method according to any one of claims 1 to 3, The glass composition does not contain alkali metal oxides (Li ₂ O, Na ₂ O, K ₂ O), the glass transition temperature (Tg) is 430 ~ 500 ℃ characterized in that the low-temperature baking at 530 ~ 580 ℃ A glass composition of a lead-free colored dielectric for PDP. The method according to any one of claims 1 to 3, The thermal expansion coefficient of the said glass composition is 60-90 (x10 <^-7> / degreeC) glass composition of the lead-free colored dielectric for PDP. The method according to any one of claims 1 to 3, The glass composition has a dielectric constant of 8 to 15, the glass composition of the lead-free colored dielectric for PDP. The method according to any one of claims 1 to 3, The glass powder of the glass composition is a glass composition of the lead-free colored dielectric for PDP, characterized in that the average particle diameter of 2 to 3㎛. A colored dielectric for PDP obtained by coating a mixture of a glass powder and a vehicle made of the glass composition of any one of claims 1 to 7 on a substrate.

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