JPH11171587A - Substrate glass for plasma display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a substrate glass for a plasma display capable of giving a high luminance color image even of NiO or CoO is added so as to obtain high contrast. SOLUTION: The glass contains 0.1-10 wt.% Nd2 O3 and is a compsn. consisting of, by weight, 50-75% SiO2 , 0.5-15% Al2 O3 , 10-27% MgO+CaO+SrO+ BaO, 7-15% Li2 O+Na2 O+K2 O, 0-9% ZrO2 , 0.5% TiO2 , 0-1% Cl, 0-1% SO3 and 0.1-10% Nd2 O3 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate glass used for a front glass substrate of a color plasma display.

[0002]

2. Description of the Related Art In a color plasma display, red, green and blue phosphors are excited by ultraviolet rays generated at the time of discharge to emit visible light, and an image formed by the emission is projected through a front glass substrate. The emission wavelength of each phosphor is as follows: red: 620 nm, green: 550 nm, blue: 460 n
m. By the way, the image surface of the color plasma display has a problem that the contrast of the image is remarkably reduced due to external light, for example, sunlight, fluorescent light or the like.

In order to improve the contrast of an image by absorbing external light, a small amount of NiO or CoO is added and colored.
Use of a front glass substrate with reduced transmittance has been studied.

[0004]

SUMMARY OF THE INVENTION However, NiO
Coloring with CoO or CoO reduces the transmittance almost uniformly over the entire visible wavelength range, so that the light emitted from the red, green, and blue phosphors is also absorbed, resulting in an undesired result in that the brightness of the image is reduced.

An object of the present invention is to provide a substrate glass for a plasma display capable of obtaining a high-luminance color image even when NiO or CoO is added to obtain a high contrast.

[0006]

As a result of various studies, the present inventor has found that the luminance can be increased by reducing the transmittance of light having a wavelength other than the emission colors of the red, green and blue phosphors. It is proposed as an invention.

That is, the substrate glass for a plasma display of the present invention is characterized by containing 0.1 to 10% by weight of Nd ₂ O ₃ .

[0008]

The substrate glass for a plasma display of the present invention contains 460 nm and 550 nm since it contains Nd ₂ O _3.
m and 620 nm wavelength, high transmission and 5
It exhibits sharp absorption for light having wavelengths of 30 nm and 586 nm. Therefore, light of a wavelength corresponding to the emission color of each phosphor (460 nm (blue), 550 nm (green), 6
20 nm (red)).
586 near 30 nm (blue-green) and between red and green
The light transmittance near nm (yellow) can be reduced.
Note that light having a wavelength corresponding to the emission color of the phosphor is
The difference between the transmittances of light having wavelengths of 586 nm and 586 nm is 2.8 in thickness.
It is preferable that the adjustment be made to be 5% or more, particularly 10% or more in mm.

In order to obtain the above-mentioned effect, Nd ₂ O ₃ is added to 0.1%.
It is necessary to contain 1% or more. However, when the content is more than 6%, especially more than 10%, the glass tends to be devitrified, and the raw material cost increases, which is not preferable.

[0010] In addition to Nd ₂ O ₃ , Er ₂ O ₃ , Cr ₂ O, or
₃ , Pr ₆ O ₁₁ may be added up to 6% in total. Further, NiO is used for fine adjustment of chromaticity and light transmittance.
2,000 ppm or less, CoO 500 ppm or less, F
It is preferable to add e ₂ O ₃ at 1% or less.

In the present invention, soda lime glass used as an architectural window glass may be used as the base glass containing Nd ₂ O _3, but SiO ₂ is used as a percentage by weight.
_{50~75%, Al 2 O 3 0.5~15} %, MgO + C
aO + SrO + BaO 10 to 27%, Li ₂ O + Na
₂ O + K ₂ O 7-15%, ZrO ₂ 0-9%, TiO
_{2 0~5%,} Cl 0~1%, it is desirable to use a high strain point glass having a composition of SO ₃ 0 to 1%. In other words, soda lime glass has a drawback that it has a low strain point and thus easily shrinks during high-temperature treatment when baking electrodes and insulating pastes, and has a low volume resistivity and the electrical resistance of the electrode material tends to change. . On the other hand, the high strain point glass having the above composition has a coefficient of thermal expansion of 75 to 95 × 10 ⁻⁷ / ° C. and has a high strain point, so that it does not easily shrink during heat treatment. Moreover, it has a characteristic that the volume resistivity is higher than that of soda lime glass.

The reason why the composition of the high strain point glass is limited as described above will be described below.

[0013] SiO ₂ is a glass network former. If the content of SiO ₂ is less than 50%, the strain point of the glass is lowered, and the glass tends to be thermally shrunk.

Al ₂ O ₃ is a component for increasing the strain point of glass. If the content of Al ₂ O ₃ is less than 0.5%, no effect is obtained, and if it is more than 15%, the thermal expansion coefficient becomes too small.

MgO, CaO, SrO and BaO are all components for facilitating melting of the glass and for controlling the coefficient of thermal expansion. If the combined amount is less than 10%, the coefficient of thermal expansion tends to be small. If the combined amount is more than 27%, the glass tends to be devitrified and molding is difficult.

Li ₂ O, Na ₂ O and K ₂ O are all components for controlling the coefficient of thermal expansion. If the total amount is less than 7%, the coefficient of thermal expansion tends to be small, and
%, The strain point becomes lower.

ZrO ₂ has the effect of improving the chemical durability, but if it exceeds 9%, the coefficient of thermal expansion becomes too small, and devitrified matters are easily formed when the glass is melted, making molding difficult.

TiO ₂ is a component for preventing the glass from being colored by ultraviolet rays, but if it exceeds 5%, the glass is liable to devitrify and molding becomes difficult.

Both Cl and SO ₃ can be added as a fining agent, but if each component is more than 1%, it is not preferable because it causes bubbles.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a substrate glass for a plasma display of the present invention will be described based on embodiments.

Table 1 shows examples of the present invention (sample No. 1).
And Comparative Examples (Sample Nos. 2 and 3).

[0022]

[Table 1]

Each sample was prepared as follows.

First, raw materials were prepared so as to have the glass composition shown in the table, put in a platinum crucible, and then placed in an electric furnace at 1450.
It was melted at a temperature of 温度 1550 ° C. for 4 hours, and the molten glass was poured out onto a carbon table and formed into a plate shape.

The obtained plate glass is optically polished on both sides,
The sample is cut into a size of × 30 × 2.8mm,
The light transmittance was measured with a spectrophotometer. FIG. 1 shows the light transmittance curve of each sample. 460 nm, 530 nm, 55
The light transmittance at 0 nm, 586 nm and 620 nm is shown in the table.

As is clear from FIG. 1 and Table 1, the sample No. No. 1 shows high transmittance for light having a wavelength corresponding to the emission color of the phosphor, and shows 72% at 460 nm, 74% at 550 nm, and 620 nm.
Showed a light transmittance of 72%. It also shows large absorption at wavelengths corresponding to 530 nm blue-green light and 586 nm yellow light, and 53% at 530 nm, 58%
At 6 nm, the light transmittance was 19%, which was lower by at least 19% than the light transmittance at each wavelength corresponding to the emission color of the phosphor.

On the other hand, the sample No. 2 and 3
Had almost no absorption at wavelengths corresponding to 530 nm blue-green light and 586 nm yellow light, and the difference from the light transmittance at each wavelength corresponding to the emission color of the phosphor was 1% or less.

[0028]

As described above, since the substrate glass for a plasma display of the present invention has selective light transmission and absorption characteristics, a plasma display with high contrast and high brightness can be manufactured. Therefore, it is suitable as a front glass substrate for a color plasma display.

[Brief description of the drawings]

FIG. 1 is a graph showing a light transmittance curve of a substrate glass at a thickness of 2.8 mm.

[Explanation of symbols]

 1 Sample No. 1 light transmittance curve 2 Sample No. 1 Light transmittance curve of No. 2 3 Sample No. 2 Light transmittance curve of 3

Claims (4)

[Claims] 1. A substrate glass for a plasma display comprising 0.1 to 10% by weight of Nd ₂ O ₃ . 2. SiO ₂ 50-75% by weight, A
l ₂ O ₃ 0.5 to 15%, MgO + CaO + SrO + B
_{aO 10~27%, Li 2 O +} Na 2 O + K 2 O 7
_{~15%, ZrO 2 0~9%,} TiO 2 0~5%, Cl
_{0~1%, SO 3 0~1%,} Nd 2 O 3 0.1~1
2. The substrate glass for a plasma display according to claim 1, having a composition of 0%. 3. The glass composition contains Er ₂ O ₃ and Cr ₂ O.
_{3. The} substrate glass for a plasma display according to claim 1, wherein one or more kinds of Pr ₆ O ₁₁ are added. 4. A glass composition containing NiO, CoO, Fe ₂
O ₃ for a plasma display substrate glass of claims 1 to 3, characterized in that with the addition of one or more.