JP2001261370A - Glass frit and glass substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass frit capable of heightening the transparency of a sintered compact for covering a transparent electrode of a plasma display panel. SOLUTION: This glass frit usable for the cover for an electrode comprises one or more kinds of compound powders selected from the group consisting of PbO2, Pb3O4, Pb(NO3)2, PbSO4, CuO, SnO2, Sb2O3, Sb2O5 and CeO2, and a glass powder, and is regulated so that the content of the powders of the compounds may be <=3.7 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass frit suitable for electrode coating or partition wall formation in a plasma display panel (PDP), a fluorescent display tube (VFD) and the like.

[0002]

2. Description of the Related Art In a PDP that has recently attracted attention as a large thin flat panel color display device, a cell is defined by a front substrate, a rear substrate, and a partition used as a display surface. Generates an image by forming a plasma discharge. On the surface of the front substrate, a transparent electrode made of ITO (indium oxide doped with tin), tin oxide or the like is formed.

In order to protect the transparent electrode from plasma, it is essential to cover the transparent electrode with glass having excellent plasma durability. This coating is usually performed by applying a glass paste obtained by forming a glass frit containing a glass powder into a paste using an organic vehicle to a transparent electrode and baking it. The organic vehicle contains a binder such as a resin and its solvent. Further, a sheet prepared by kneading the glass frit with a resin is attached to a transparent electrode and fired.

[0004]

In order to improve the image quality of the PDP, it is required that the glass frit used for coating the transparent electrode has higher transparency of a fired body obtained by firing the glass frit. ing. An object of the present invention is to provide a glass frit that solves this problem and a glass substrate using the glass frit.

[0005]

SUMMARY OF THE INVENTION The present invention provides a PbO_Two, P
b (NO_Three)_Two, PbSO_Four, CuO, SnO_Two, Sb
_TwoO _Three, Sb_TwoO_FiveAnd CeO_TwoSelected from the group consisting of
A powder containing at least one compound powder and glass powder;
Content is 3.7% or less in terms of mass percentage
Provide a glass frit (first glass frit).
Also, PbO_Two, Pb_ThreeO_Four, Pb (NO_Three)_Two, PbS
O_Four, CuO, SnO_Two, Sb_TwoO_Three, Sb_TwoO_FiveAnd Ce
O_TwoOne or more compound powders selected from the group consisting of
Glass powder, and the content of the compound powder is in terms of mass percentage.
Gas used for electrode coating, which is 3.7% or less in terms of percentage
Provide a lath frit (second glass frit). Sa
Further, a glass substrate on which a transparent electrode is formed,
The transparent electrode is covered with the fired body of the glass frit.
To provide a glass substrate.

The inventor of the present invention has found that the cause of the reduction in the transparency of the fired body of glass frit used for coating the transparent electrode is the coloring of the fired body and / or bubbles in the fired body. The present inventors have presumed that the cause of the coloring and / or the bubbles is residual carbon-containing impurities described below in the fired body, and have reached the present invention.

That is, most of the carbon-containing impurities present in the organic vehicle and the like are volatilized and escaped by the reaction with oxygen and the like in the firing atmosphere during firing of the glass frit, but some of the carbon-containing impurities are volatilized.・ Escape does not occur and remains on the sintered body of glass frit. The residual carbon-containing impurities color the fired body. In addition, the residual carbon-containing impurities generate bubbles such as carbon dioxide gas during the firing.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The glass frit of the present invention is usually made into a glass paste by an organic vehicle, and this glass paste is applied to a glass substrate or the like and fired to obtain a fired body. The method for forming the fired body is not limited to this. For example, a sheet may be prepared by kneading and molding a glass frit with a resin, and the sheet may be attached to a glass substrate or the like and fired. The glass transition point of a glass substrate used for a PDP or the like is usually 550 to 620 ° C.
The firing of the glass frit applied to the glass substrate is performed at 620 ° C. or lower.

[0009] The first glass frit of the present invention comprises PbO ₂ , Pb
(NO ₃ ) ₂ , PbSO ₄ , CuO, SnO ₂ , Sb ₂ O ₃ ,
One or more compound powders selected from the group consisting of Sb ₂ O ₅ and CeO ₂ are contained as essential components. The second glass frit of the present invention includes PbO ₂ , Pb ₃ O ₄ , Pb (NO ₃ ) ₂ ,
One or more compound powders selected from the group consisting of PbSO ₄ , CuO, SnO ₂ , Sb ₂ O ₃ , Sb ₂ O ₅ and CeO ₂ are contained as essential components.

[0010] The first glass frit and the second glass frit of the present invention.
In the glass frit, the compound powder, during firing of the glass frit, reacts with the glass powder or glass generated by softening or melting the glass powder to generate oxygen, and the oxygen reacts with carbon-containing impurities, It is believed that the residual carbon-containing impurities are reduced.

The total content of the compound powder is as follows:
It is 3.7% or less in terms of mass percentage. If it exceeds 3.7%, the generation of the oxygen is too large, and the generation of bubbles due to this is increased, which in turn lowers the transparency of the fired body. It is preferably at most 3%, more preferably at most 2%, particularly preferably at most 1%. Hereinafter, the content in the present invention is shown by mass percentage.

The total content of the compound powder is preferably 0.1% or more. If it is less than 0.1%, the effect of reducing residual carbon-containing impurities may be too small. It is more preferably at least 0.2%, particularly preferably at least 0.3%.

The average particle size of the compound powder is 0.5
It is preferably at least μm. If it is less than 0.5 μm,
There is a possibility that the number of air bubbles in the fired body is increased and the transparency of the fired body is reduced, or a time for forming the powder is too long. It is more preferably at least 0.7 μm.
Further, the maximum particle size of the compound powder is preferably 35 μm or less. The thickness of the fired body covering the transparent electrode of PDP is usually 40 μm or less, but the maximum particle size is 35 μm.
If it exceeds μm, irregularities are generated in the fired body, and the transparency of the fired body may be reduced. More preferably, it is 20 μm or less.

The first glass frit and the second glass frit contain glass powder as an essential component. The softening point of the glass powder is preferably from 450 to 650 ° C. If it exceeds 650 ° C., the glass flow during firing may be insufficient. It is more preferably 640 ° C or lower, particularly preferably 630 ° C or lower. When there is no contact with a metal electrode, the softening point is more preferably 500 ° C or lower, and most preferably 490 ° C or lower.

If the temperature is lower than 450 ° C., the metal electrode may be eroded or the erosion of the transparent electrode via the metal electrode may be accelerated. It is more preferably at least 460 ° C, particularly preferably at least 470 ° C. When there is contact with a metal electrode or the like, the softening point is more preferably 550 ° C or more, most preferably 560 ° C or more. The metal electrode referred to here is a metal layer formed on the transparent electrode when the electric resistance of the transparent electrode alone is too high.
Examples thereof include a layer, an Al layer, and a Cr-Cu-Cr layer having a three-layer structure.

The average linear expansion coefficient α of the glass powder at 50 to 350 ° C. is preferably 60 × 10 ^{−7 to} 100 × 10 ⁻⁷ / ° C. If it is less than 60 × 10 ⁻⁷ / ° C., the glass substrate may be warped. More preferably 7
0 × 10 ⁻⁷ / ° C. or higher. If it exceeds 100 × 10 ⁻⁷ / ° C., the strength of the glass substrate may decrease. More preferably 90 × 10 ⁻⁷ / ° C. or less, particularly preferably 85 × 10 ⁻⁷ / ° C.
^-7 / ° C or less.

The glass powder is represented by the following oxide percentage mass percentage: 25 to 85% of PbO, 0 to 60% of B ₂ O _3, 0 to 40% of SiO _2, 0 to 25% of Al ₂ O ₃ , Bi _{2 O 3 0~35%, MgO + CaO} + SrO + BaO 0~40%, ZnO 0~55%, Li 2 O + Na 2 O + K 2 O 0~20%, preferably consists essentially of. In addition, components other than the above components may be contained within a range that does not impair the object of the present invention, but the content of these components is preferably 20% or less. It is more preferably at most 10%.

The glass frit of the present invention may contain other powders in addition to the compound powder and the glass powder as long as the object of the present invention is not impaired. Examples of such a powder include fillers and pigments, and the content of the other powder is preferably 30% or less.

The glass substrate of the present invention is manufactured, for example, as follows. That is, the glass frit of the present invention is applied on the transparent electrode formed on the surface thereof and fired, thereby producing a fired body covering the transparent electrode.

[0020]

EXAMPLE A prepared raw material was melted in a platinum crucible at 1350 ° C. for 1 hour, and the composition expressed by mass percentage was PbO: 4.
_{0.5%, B 2 O 3:} 30.3%, SiO 2: 8.2%,
Al ₂ O ₃ : 3.7%, BaO: 17.3%, a thin plate glass was produced. This thin glass was pulverized with a ball mill to produce glass powder A. The softening point of this glass powder A was 595 ° C., and α was 75 × 10 ⁻⁷ / ° C.

Similarly, the composition expressed by mass percentage is P
_{bO: 65%, B 2 O} 3: 21.3%, SiO 2: 2.3
%, Al ₂ O ₃ : 3.9%, ZnO: 7.5%, to prepare a glass powder B. The softening point of this glass powder B was 485 ° C., and α was 81 × 10 ⁻⁷ / ° C.

Next, glass powder A or B and PbO ₂
A sample powder containing the powder and the Pb ₃ O ₄ powder in the proportions shown by mass percentage in the table was prepared. Glass powder in sample powders 1 to 6 is glass powder A, and sample powder 7 to
The glass powder in 12 is glass powder B. Also,
The average particle size of both the PbO ₂ powder and the Pb ₃ O ₄ powder is 0.1.
8 μm and the maximum particle size were all 5 μm. Sample powders 1 to 4, 7 to 10 are examples, and sample powders 5, 6, 11, 1
2 is a comparative example.

Further, with respect to the sample powders 1 to 6, 80 g and 20 g of the organic vehicle were kneaded to obtain glass paste. As the organic vehicle, a solution prepared by dissolving 10% by mass of ethyl cellulose in α-terpineol was used. For sample powders 7 to 12, 60 g and 40 g of organic vehicle were kneaded, respectively.
Glass paste was used. As the organic vehicle, ethyl cellulose was added to α-terpineol in terms of mass percentage.
A solution dissolved at 0% was used.

2.8 mm thick, 50 mm × 75 m
m glass substrate having an ITO transparent electrode formed on the surface of a soda lime silica glass plate (α: 87 × 10 ⁻⁷ /
C), the glass paste was applied by a screen printing method or the like. The glass substrate on which the glass paste was applied was dried at 120 ° C. for 10 minutes, and then fired at 570 ° C. for 30 minutes to form a fired body on the ITO transparent electrode.

The transmittance (unit:%) and turbidity (unit:%) of the glass substrate on which the fired body was formed were measured by the methods described below. The results are shown in the table. Transmittance: wavelength of 550 nm using an integrating sphere type self-recording spectrophotometer (trade name: U-3500, manufactured by Hitachi, Ltd.)
Was measured. It is preferably at least 80%. Turbidity: Total light transmittance _Tt and diffuse transmittance _Td were measured with an integrating sphere type haze meter (manufactured by Suga Test Instruments Co., Ltd.) using a C light source, and ( _Td / _Tt ) × 100 was measured. Turbidity was taken. It is preferably at most 15%.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

According to the present invention, it is possible to increase the transparency of a fired body covering a transparent electrode of PDP or VFD, and as a result, P
The image quality of DP and VFD is improved.

Continued on the front page F-term (reference) 4G062 AA08 AA09 AA15 BB04 DA01 DA02 DA03 DA04 DA05 DB01 DB02 DB03 DB04 DC01 DC02 DC03 DC04 DC05 DC06 DD01 DE01 DE02 DE03 DE04 DE05 DE06 DF04 DF05 DF06 DF07 EA01 EA02 EA03 EB04 EB03 EC02 EC03 EC04 ED01 ED02 ED03 ED04 ED05 EE01 EE02 EE03 EE04 EE05 EF01 EF02 EF03 EF04 EF05 EG01 EG02 EG03 EG04 EG05 FA01 FA10 FB01 FC01 FD01 FE01 FF01 FG01 F01G01 H01 GA01 GA01 HH11 HH13 HH15 HH17 HH20 JJ01 JJ03 JJ05 JJ07 JJ10 KK01 KK03 KK05 KK07 KK10 MM05 MM12 NN26 NN29 NN32 PP01 PP11

Claims (6)

[Claims] (1) PbO_Two, Pb (NO_Three)_Two, PbSO_Four, C
uO, SnO_Two, Sb_TwoO_Three, Sb_TwoO _FiveAnd CeO_TwoFrom
At least one compound powder and glass powder selected from the group consisting of:
And the content of the compound powder is represented by mass percentage.
Glass frit of not more than 3.7%. 2. PbO_Two, Pb_ThreeO_Four, Pb (NO_Three)_Two, P
bSO_Four, CuO, SnO_Two, Sb_TwoO _Three, Sb_TwoO_Fiveand
CeO_TwoAt least one compound powder selected from the group consisting of
And glass powder, and the content of the compound powder is mass
3.7% or less in percent, used for electrode coating
Glass frit. 3. The glass frit according to claim 1, wherein the softening point of the glass powder is 450 to 650 ° C. 4. The glass frit according to claim 1, wherein the average thermal expansion coefficient of the glass powder at 50 to 350 ° C. is in the range of 60 × 10 ^{−7 to} 100 × 10 ⁻⁷ / ° C. 5. A glass powder comprising: 25 to 85% of PbO, 0 to 60% of B ₂ O _3, 0 to 40% of SiO _2, 0 to 25% of Al ₂ O ₃ , in terms of mass percentage based on the following oxides: 5. The method according to claim 1, which substantially consists of 0 to 35% of Bi ₂ O ₃ , 0 to 40% of MgO + CaO + SrO + BaO, 0 to 55% of ZnO, and 0 to 20% of Li ₂ O + Na ₂ O + K ₂ O. Glass frit. 6. A glass substrate on which a transparent electrode is formed, wherein the transparent electrode is covered with the fired body of the glass frit according to claim 1.