WO1998049111A1 - Glass compositions used in plasma displays - Google Patents

Glass compositions used in plasma displays Download PDF

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Publication number
WO1998049111A1
WO1998049111A1 PCT/GB1998/001227 GB9801227W WO9849111A1 WO 1998049111 A1 WO1998049111 A1 WO 1998049111A1 GB 9801227 W GB9801227 W GB 9801227W WO 9849111 A1 WO9849111 A1 WO 9849111A1
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Prior art keywords
composition
amount
less
oxide
range
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PCT/GB1998/001227
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French (fr)
Inventor
Kenneth Melvin Fyles
Ashley Carl Torr
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Pilkington Plc
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Priority claimed from GBGB9708564.1A external-priority patent/GB9708564D0/en
Priority claimed from GBGB9712681.7A external-priority patent/GB9712681D0/en
Application filed by Pilkington Plc filed Critical Pilkington Plc
Priority to AU72198/98A priority Critical patent/AU7219898A/en
Publication of WO1998049111A1 publication Critical patent/WO1998049111A1/en

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
    • C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
    • C03C3/087—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal containing calcium oxide, e.g. common sheet or container glass

Definitions

  • the present invention relates to a glass composition. More particularly, the present invention relates to a composition for making a glass primarily intended for use in plasma display panels (PDPs).
  • PDPs plasma display panels
  • PDP are a sub-division of the type of devices known as vacuum fluorescent displays. Such panels generally comprise two sheets of flat glass defining a gap there between. A gas at low pressure is located in the gap and is subjected to an electrical discharge. The gas ionises and emits ultra-violet radiation which, in turn, is caused to strike a phosphor so as to cause radiation having a wavelength in the visible portion of the electromagnetic spectrum to be emitted.
  • the manner in which such devices operate is well known and forms no part of the present invention.
  • United States Patent Specification No 5459109 describes and claims substrate glasses suitable for use in these devices.
  • the most commonly used type of glass is a soda-lime-silica glass formed by the float process although this is not ideal for modern uses.
  • Such prior specification also discusses, at some length, the three major properties which must be exhibited by the substrate glass. These are (a) the strain point of the glass, (b) the coefficient of thermal expansion of the glass and (c) ease of manufacture in a conventional flat glass-making furnace.
  • United States Patent Specification No 5459109 discloses a glass composition which is free from alkali metal oxides (other than those present as impurities in the raw materials). It is stated that these oxides have an adverse effect on the electrical properties of the deposited electrode and dielectric materials.
  • the present invention seeks to provide a glass composition which meets the three criteria set forth in United States Patent Specification No 5459109 but which has a substantially lower density. Additionally, the present invention seeks to provide a composition in which the amount of expensive, heavy oxides, such as those of strontium and barium, is substantially reduced, or even eliminated, compared with the composition of said prior art document.
  • R represent a Group I (alkali) metal and R' represent a Group II (alkaline earth) metal oxide, the total amount of the SiO 2 , Al 2 O 3 and ZrO 2 being greater than 71%, each of BaO and SrO being present in a minimum amount of 0.5% and the total amount of BaO and SrO included in the R'O lies within the range of 1% to 8%.
  • compositions for producing a glass having a strain point in excess of 570°C, a coefficient of thermal expansion lying within the range of 75 x 10 "7 /°C and 90 x 10 "7 /°C over the temperature range of 100 Q C to 300°C, a density of less than 2.70g/cm 3 and a viscosity at its liquidus temperature of at least 3000 poise comprising, in weight % on the basis of the oxide:- SiO 2 56% to 72%
  • R represents a Group I (alkali metal) oxide and R' represents a Group II (alkaline earth metal) oxide
  • the amount of K 2 O included in the R 2 O being less than 4% the total amount of the SiO ⁇ Al 2 O 3 and ZrO 2 being greater than 71%
  • the total amount of BaO and SiO, if present, included in the R'O being a maximum of 8%.
  • the different types of metal oxides used in the composition of the present invention each have a beneficial effect on one or more of the desired properties but, in general, have a disadvantageous or, at best, neutral effect on the other properties.
  • Group I metal oxides tend to increase the coefficient of expansion of the glass relative to that of the silica and also lower the liquidus temperature. However, instead of improving the strain point, they actually lower it.
  • Group II metal oxides slightly increase the coefficient of expansion and have a neutral effect on the strain point. On the other hand, they increase the liquidus temperature although this effect decreases with increasing atomic weight. Aluminium oxide and zirconium oxide both improve the strain point but adversely affect the liquidus temperature, at least compared with Group I metal oxides.
  • the first of which is the use of aluminium oxide, either in the presence or absence of zirconium oxide, in amounts which have the desired effect on the strain point.
  • devitrification temperatures increase as the amount of aluminium oxide is increased and we have determined that the upper limit for the amount present is 11%.
  • the second important consideration is to use as much R'O (Group II metal oxides), particularly calcium oxide and magnesium oxide as is feasible until an unacceptable adverse effect on the liquidus temperature is reached but, since they have an adverse effect on the density of the glass, the maximum amount of such oxides is limited.
  • lithium oxide has an adverse effect on the strain point but has a very beneficial effect on the ease of melting of the glass.
  • Sodium oxide has much the same characteristics as lithium oxide but to a lesser extent It does, however, improve the coefficient of thermal expansion of the glass to such an extent that it lies within the range required by the present invention.
  • potassium oxide has less of an adverse effect on the strain point, it causes problems during the melting of the glass. In particular, it causes both foam and bubble. Bubble, particularly, is unacceptable in the finished glass. For this reason, the amount of potassium oxide is maintained below 4%.
  • the amount of Li 2 O is less than 0.3% with the amount of Na 2 O lying within the range of 8% to 10%.
  • the amount of K 2 O is preferably less than 3%.
  • the amount of CaO lies within the range of 7% to 9% and if the amount of MgO lies within the range of 2% to 4%.
  • Aluminium oxide, Al 2 O 3 is a major constituent of the composition of the present invention in that it greatly assists in raising the strain point of the glass and has a controlling effect on the liquidus temperature. As mentioned hereinbefore, large amounts of aluminium oxide increase the devitrification temperature of the glass. To achieve the desired beneficial effects without risking the disadvantages, it is preferred if the amount of aluminium oxide present lies within the range of 7% to 10%.
  • B 2 O 3 Boron oxide, B 2 O 3 , may also be included in the composition. Its presence lowers the melt viscosity of the glass and assists in reducing the liquidus temperature. It does, however, have the disadvantage of being very corrosive insofar as the refractory materials used in a float glass tank are concerned. If used, therefore, the amount of B 2 O 3 in the composition is preferably less than 5%.
  • Phosphorus pentoxide (P 2 O 5 ) is similar to B 2 O 3 in that it corrosively attacks the refractory materials of a float glass tank. It does, however, improve the strain point and also is an aid in the melting of the glass. If more than 3% phosphorus pentoxide is present in the composition, the liquidus temperature is significantly higher and, in fact, it is preferred if the amount thereof is limited to 2%.
  • titanium dioxide TiO 2
  • the amount of such oxide is excessive or if lower amounts of the oxide are used in conjunction with any materials containing large impurity amounts of iron, titanium dioxide gives an unacceptable yellow coloration to the glass. It is therefore preferred that the amount of titanium dioxide, if present in the composition, is no more than 2%.
  • Zirconium oxide helps to raise the strain point of the glass but simultaneously raises the melt viscosity of the glass. Furthermore, it tends, in conjunction with the aluminium oxide, to push up the liquidus temperature of the glass. We have found that if the amount of aluminium oxide present is less than 10% and the total of zirconium oxide is added at the expense of SiO 2 , the adverse effect on the melt viscosity of the glass is greatly reduced. Similarly, the liquidus temperature increase is kept within acceptable limits.
  • a disadvantage is that the density of the glass is increased but by no more than 0.1, desirably no more than 0.05, g/cm 3 .
  • various other oxides may be added to the compositions of the present invention so as to modify their optical properties.
  • Typical of such oxides are lanthanum oxide (La 2 O 3 ), yttrium oxide (Y 2 O 3 ), zinc oxide (ZnO), tantalum pentoxide (Ta 2 O 5 ) and tin oxide (SnO 2 ).
  • conventional tinting agents such as iron oxide (Fe 2 O 3 ), cobalt oxide (CoO) and selenium (Se) may be included. If used, the total amount of these additional oxides should not exceed 4% and preferably, not more than 2%.
  • a refining aid such as SO 3 may be included in the composition, preferably in an amount lying within the range of 0.05% to 0.4%.
  • Table 1 examples are given of compositions in accordance with the present invention.
  • Table 2 various properties of glasses formed from some of the compositions of Table 1 are given.

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Glass Compositions (AREA)

Abstract

A composition suitable for producing a plasma display panel glass having a density of less than 2.70 g/cm3 and a viscosity at its liquidus temperature of at least 3000 poise, the composition comprising, in weight % on the basis of the oxide: SiO¿2? 56 % to 72 %; R2O 8 % to 14 %; R'O 10 % to 17 %; Al2O3 5 % to 11 %; B2O3 0 % to 5 %; ZrO2 0 % to 7 %; TiO2 0 % to 2 %; P2O5 0 % to 3 %; where R represents a Group I (alkali metal) oxide and R' represents a Group II (alkaline earth metal) oxide, the amount of K2O included in the R2O being less than 4 %, the total amount of the SiO2, Al2O3 and ZrO2 being greater than 71 %, the total amount of BaO and SrO, if present, included in the R'O being a maximum of 8 %.

Description

GLASS COMPOSITIONS USED IN PLASMA DISPLAYS
The present invention relates to a glass composition. More particularly, the present invention relates to a composition for making a glass primarily intended for use in plasma display panels (PDPs).
PDP are a sub-division of the type of devices known as vacuum fluorescent displays. Such panels generally comprise two sheets of flat glass defining a gap there between. A gas at low pressure is located in the gap and is subjected to an electrical discharge. The gas ionises and emits ultra-violet radiation which, in turn, is caused to strike a phosphor so as to cause radiation having a wavelength in the visible portion of the electromagnetic spectrum to be emitted. The manner in which such devices operate is well known and forms no part of the present invention.
United States Patent Specification No 5459109 describes and claims substrate glasses suitable for use in these devices. In this prior art document, it is pointed out that the most commonly used type of glass is a soda-lime-silica glass formed by the float process although this is not ideal for modern uses. Such prior specification also discusses, at some length, the three major properties which must be exhibited by the substrate glass. These are (a) the strain point of the glass, (b) the coefficient of thermal expansion of the glass and (c) ease of manufacture in a conventional flat glass-making furnace.
In United States Patent Specification No 5459109, the three desired properties are achieved by using a composition which is essentially free of alkali metal oxides. Instead, alkaline earth metal oxides are used at a minimum level of 45.5 weight %. Of this, strontium oxide and barium oxide must account for at least 36 weight %. Whilst this composition may well produce glasses having the desired characteristics, it does have one major disadvantage.
Such disadvantage is the one further major property which is becoming ever more important. This is the density of the glass. PDP are used, inter alia, in television screens and video display units. The former, particularly, are being made larger and larger and it will be readily appreciated that any increase in size necessarily incurs a corresponding increase in weight. The Examples of glasses disclosed in United States Patent Specification No 5459109, have a density far in excess of 2.70g/cm3 and, in fact, none has a density of less than 3.3 g/cm3.
As stated previously, United States Patent Specification No 5459109 discloses a glass composition which is free from alkali metal oxides (other than those present as impurities in the raw materials). It is stated that these oxides have an adverse effect on the electrical properties of the deposited electrode and dielectric materials.
The present invention seeks to provide a glass composition which meets the three criteria set forth in United States Patent Specification No 5459109 but which has a substantially lower density. Additionally, the present invention seeks to provide a composition in which the amount of expensive, heavy oxides, such as those of strontium and barium, is substantially reduced, or even eliminated, compared with the composition of said prior art document.
According to the present invention, there is provided a composition for producing a glass having a strain point in excess of 570δC, a coefficient of thermal expansion lying within the range of 75 x lO'^C and 90 x lσ C over the temperature range of 100°C to 300°C, a density of less than 2.70g/cm3 and a viscosity at its liquidus temperature of at least 3000/poise, the composition comprising, in weight % on the basis of the oxide:-
SiO2 56% to 70%
R2O 8% to 14%
R'O 10% to 17%
Al2O3 5% to 11%
B2O3 0% to 5%
ZrO2 0% to 7%
TiO2 0% to 2%
P2O5 0% to 3%
where R represent a Group I (alkali) metal and R' represent a Group II (alkaline earth) metal oxide, the total amount of the SiO2, Al2O3 and ZrO2 being greater than 71%, each of BaO and SrO being present in a minimum amount of 0.5% and the total amount of BaO and SrO included in the R'O lies within the range of 1% to 8%.
Also according to the present invention, there is provided a composition for producing a glass having a strain point in excess of 570°C, a coefficient of thermal expansion lying within the range of 75 x 10"7/°C and 90 x 10"7/°C over the temperature range of 100QC to 300°C, a density of less than 2.70g/cm3 and a viscosity at its liquidus temperature of at least 3000 poise, the composition comprising, in weight % on the basis of the oxide:- SiO2 56% to 72%
R2O 8% to 14%
R'O 10% to 17%
Al2O3 5% to 11%
B2O3 0% to 5%
ZrO2 0% to 7%
TiO2 0% to 2%
Figure imgf000005_0001
where R represents a Group I (alkali metal) oxide and R' represents a Group II (alkaline earth metal) oxide, the amount of K2O included in the R2O being less than 4% the total amount of the SiO^ Al2O3 and ZrO2 being greater than 71%, the total amount of BaO and SiO, if present, included in the R'O being a maximum of 8%.
To achieve the desiderata of the present invention using the prior art as a basis is not straightforward. In particular, the different types of metal oxides used in the composition of the present invention each have a beneficial effect on one or more of the desired properties but, in general, have a disadvantageous or, at best, neutral effect on the other properties.
For example, Group I metal oxides tend to increase the coefficient of expansion of the glass relative to that of the silica and also lower the liquidus temperature. However, instead of improving the strain point, they actually lower it. Similarly, Group II metal oxides slightly increase the coefficient of expansion and have a neutral effect on the strain point. On the other hand, they increase the liquidus temperature although this effect decreases with increasing atomic weight. Aluminium oxide and zirconium oxide both improve the strain point but adversely affect the liquidus temperature, at least compared with Group I metal oxides.
We have therefore ascertained that there are important factors in the present invention, the first of which is the use of aluminium oxide, either in the presence or absence of zirconium oxide, in amounts which have the desired effect on the strain point. However, devitrification temperatures increase as the amount of aluminium oxide is increased and we have determined that the upper limit for the amount present is 11%. The second important consideration is to use as much R'O (Group II metal oxides), particularly calcium oxide and magnesium oxide as is feasible until an unacceptable adverse effect on the liquidus temperature is reached but, since they have an adverse effect on the density of the glass, the maximum amount of such oxides is limited.
With regard to the Group I metal oxides, lithium oxide has an adverse effect on the strain point but has a very beneficial effect on the ease of melting of the glass. Sodium oxide has much the same characteristics as lithium oxide but to a lesser extent It does, however, improve the coefficient of thermal expansion of the glass to such an extent that it lies within the range required by the present invention. Whilst potassium oxide has less of an adverse effect on the strain point, it causes problems during the melting of the glass. In particular, it causes both foam and bubble. Bubble, particularly, is unacceptable in the finished glass. For this reason, the amount of potassium oxide is maintained below 4%.
For those reasons, we have found that it is highly desirable if the amounts of the other two oxides are limited as follows :-
Ii2O < 0.5%
Na2O 7% to 12%
It is particularly desirable if the amount of Li2O is less than 0.3% with the amount of Na2O lying within the range of 8% to 10%. The amount of K2O is preferably less than 3%.
Turning now to the Group II metal oxides, the alkaline earth metal oxides, each of these has different effects. Thus, both MgO and CaO are useful in lowering the high temperature viscosity of the glass without adversely affecting the strain point. However, as the amount of these oxides is increased, the liquidus temperature is increased. The use of strontium and barium oxides do reduce these disadvantageous effects but they, together with CaO to a lesser extent, increase the density of the glass.
With these problems in mind, it is advantageous if the amounts of these oxides are limited as follows:-
MgO < 5%
CaO 4% to 10%
BaO < 3%
BaO + SrO < 6%
It is particularly desirable if the amount of CaO lies within the range of 7% to 9% and if the amount of MgO lies within the range of 2% to 4%. Aluminium oxide, Al2O3, is a major constituent of the composition of the present invention in that it greatly assists in raising the strain point of the glass and has a controlling effect on the liquidus temperature. As mentioned hereinbefore, large amounts of aluminium oxide increase the devitrification temperature of the glass. To achieve the desired beneficial effects without risking the disadvantages, it is preferred if the amount of aluminium oxide present lies within the range of 7% to 10%.
Boron oxide, B2O3, may also be included in the composition. Its presence lowers the melt viscosity of the glass and assists in reducing the liquidus temperature. It does, however, have the disadvantage of being very corrosive insofar as the refractory materials used in a float glass tank are concerned. If used, therefore, the amount of B2O3 in the composition is preferably less than 5%.
Phosphorus pentoxide (P2O5) is similar to B2O3 in that it corrosively attacks the refractory materials of a float glass tank. It does, however, improve the strain point and also is an aid in the melting of the glass. If more than 3% phosphorus pentoxide is present in the composition, the liquidus temperature is significantly higher and, in fact, it is preferred if the amount thereof is limited to 2%.
To lower the melt viscosity of the glass whilst maintaining a high strain point, titanium dioxide (TiO2) may be employed. If, however, the amount of such oxide is excessive or if lower amounts of the oxide are used in conjunction with any materials containing large impurity amounts of iron, titanium dioxide gives an unacceptable yellow coloration to the glass. It is therefore preferred that the amount of titanium dioxide, if present in the composition, is no more than 2%.
Zirconium oxide (ZrO2) helps to raise the strain point of the glass but simultaneously raises the melt viscosity of the glass. Furthermore, it tends, in conjunction with the aluminium oxide, to push up the liquidus temperature of the glass. We have found that if the amount of aluminium oxide present is less than 10% and the total of zirconium oxide is added at the expense of SiO2, the adverse effect on the melt viscosity of the glass is greatly reduced. Similarly, the liquidus temperature increase is kept within acceptable limits. A disadvantage is that the density of the glass is increased but by no more than 0.1, desirably no more than 0.05, g/cm3. It will be readily apparent to those skilled in the art that minor modifications may be made to the present invention without departing from the scope thereof. Thus, for example, various other oxides may be added to the compositions of the present invention so as to modify their optical properties. Typical of such oxides are lanthanum oxide (La2O3), yttrium oxide (Y2O3), zinc oxide (ZnO), tantalum pentoxide (Ta2O5) and tin oxide (SnO2). Moreover, conventional tinting agents such as iron oxide (Fe2O3), cobalt oxide (CoO) and selenium (Se) may be included. If used, the total amount of these additional oxides should not exceed 4% and preferably, not more than 2%. Moreover, a refining aid such as SO3 may be included in the composition, preferably in an amount lying within the range of 0.05% to 0.4%.
The invention will be further described, by way of illustration only, with reference to the two following Tables. In Table 1, examples are given of compositions in accordance with the present invention. In Table 2, various properties of glasses formed from some of the compositions of Table 1 are given.
Figure imgf000009_0001
0
Figure imgf000010_0001
Figure imgf000011_0001
Figure imgf000012_0001
Figure imgf000013_0001
Figure imgf000014_0001

Claims

1. A composition for producing a glass having a strain point in excess of 570┬░C, a coefficient of thermal expansion lying within the range of 75 x 10"7/┬░C and 90 x 10"7/┬░C over the temperature range of 100┬░C to 300QC, a density of less than 2.70g/cm3 and a viscosity at its liquidus temperature of at least 3000 poise, the composition comprising, in weight % on the basis of the oxide:-
SiO2 56% to 72%
R2O 8% to 14%
R'O 10% to 17%
Al2O3 5% to 11%
B2O3 0% to 5%
ZrO2 0% to 7%
TiO2 0% to 2%
P2O5 0% to 3% where R represents a Group I (alkali metal) oxide and R' represents a Group II (alkaline earth metal) oxide, the amount of K2O included in the R2O being less than 4%, the total amount of the SiO2, Al2O3 and ZrO2 being greater than 71%, each of BaO and SrO being present in a minimum amount of 0.5% and the total amount of BaO and SrO included in the R'O lying within the range of 1% to 8%.
2. A composition for producing a glass having a strain point in excess of 5709C, a coefficient of thermal expansion lying within the range of 75 x 10"7/┬░C and 90 x 10"7/┬░C over the temperature range of 100┬░C to 300┬░C, a density of less than 2.70g/cm3 and a viscosity at its liquidus temperature of at least 3000 poise, the composition comprising, in weight % on the basis of the oxide: -
SiO2 56% to 72%
R2O 8% to 14%
R'O 10% to 17%
Al2O3 5% to 11%
B2O3 0% to 5% ZrO2 0% to 7%
TiO2 0% to 2%
Figure imgf000016_0001
where R represents a Group I (alkali metal) oxide and R' represents a Group π (alkaline earth metal) oxide, the amount of K2O included in the R2O being less than 4%, the total amount of the SiO_, Al2O3 and ZrO2 being greater than 71%, the total amount of BaO and SrO, if present, included in the R'O being a maximum of 8%.
3. A composition as claimed in claim 1 or 2 wherein the R2O component comprises Na2O in an amount of from 7% to 12% either alone or in admixture with K2O in an amount of less than 4% and/or lithium oxide in a maximum amount of 0.5%.
4. A composition as claimed in claim 3 wherein the maximum amount of Li2O is 0.3%.
5. A composition as claimed in any preceding claim wherein the maximum amount of K2O is 3%, optimally 2%.
6. A composition as claimed in any one of claims 3 to 5 wherein the amount of Na2O lies within the range of from 8% to 10%.
7. A composition as claimed in any preceding claim wherein the R'O oxides component comprises a mixture of MgO, CaO, BaO and SrO.
8. A composition as claimed in claim 7 wherein the amount of CaO in the composition lies within the range of 7% to 9%.
9. A composition as claimed in claim 7 or 8 wherein the amount of MgO in the composition lies within the range of 2% to 4%.
10. A composition as claimed in any one of claims 7 to 9 wherein the maximum amount of BaO in the composition is 3%.
11. A composition as claimed in any one of claims 7 to 10 wherein the total amount of the BaO plus the SrO lies within the range of from 1% to 6%.
12. A composition as claimed in any preceding claim in which the sum of the R'O oxides lies in the range of from 11% to 14%.
13. A composition as claimed in any preceding claim wherein the amount of Al2O3 in the composition lies within the range of from 7% to 10%.
14. A composition as claimed in any preceding claim in which B2O3 is present in the composition in an amount less than 5%.
15. A composition as claimed in any preceding claim in which P2Os is present in the composition in an amount less than 3%.
16. A composition as claimed in any preceding claim in which TiO2 is present in the composition in an amount of less than 2%.
17. A composition as claimed in any preceding claim in which ZrO2 is present in an amount of less than 7%, and the Al2O3 being present in an amount of less than 10% so that the total amount of ZrO2 plus Al2O3 is less than 17%, the ZrO2 being included in the composition at the expense of SrO2.
18. A composition as claimed in any preceding claim additionally including one or more of La2O3, Y2O3, ZnO, Ta2O5 and SnO in a total amount of less than 4%, optimally less than 2%.
19. A composition as claimed in any preceding claim additionally including SO3 in an amount lying in the range of 0.05% to 0.4%.
20. A composition as claimed in any preceding claim having a density of less than 2.65.
21. A glass formed from a composition as claimed in any one of claims 1 to 20.
22. A plasma display panel comprising a pair of glass plates as claimed in claim 21 separated by a gas at low pressure.
PCT/GB1998/001227 1997-04-29 1998-04-27 Glass compositions used in plasma displays WO1998049111A1 (en)

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GB9712681.7 1997-06-18

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EP0953549A1 (en) * 1998-04-28 1999-11-03 Asahi Glass Company Ltd. Plate glass and substrate glass for electronics
US6297182B1 (en) 1998-08-11 2001-10-02 Asahi Glass Company Ltd. Glass for a substrate
DE10214449A1 (en) * 2002-03-30 2003-10-23 Schott Glas Production of an aluminosilicate glass comprises adding at least one refining agent to the starting materials, melting, and hot molding the molten glass
WO2011035889A1 (en) * 2009-09-25 2011-03-31 Schott Ag Aluminosilicate glass having high thermal stability and low processing temperature
US20120172190A1 (en) * 2009-08-03 2012-07-05 Hong Li Glass Compositions And Fibers Made Therefrom
WO2015195435A3 (en) * 2014-06-19 2016-03-24 Corning Incorporated Aluminosilicate glasses
US9446983B2 (en) 2009-08-03 2016-09-20 Ppg Industries Ohio, Inc. Glass compositions and fibers made therefrom
WO2016151327A1 (en) * 2015-03-26 2016-09-29 Pilkington Group Limited Glasses
WO2016151322A1 (en) * 2015-03-26 2016-09-29 Pilkington Group Limited Novel glasses
WO2016151325A1 (en) * 2015-03-26 2016-09-29 Pilkington Group Limited Glasses
WO2016151324A1 (en) * 2015-03-26 2016-09-29 Pilkington Group Limited Novel glasses
US11951713B2 (en) 2020-12-10 2024-04-09 Corning Incorporated Glass with unique fracture behavior for vehicle windshield

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