# US 7,612,004 B2 · High strain point glasses

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- Number: US 7,612,004 B2
- Document ID: US7612004B2
- Status: Granted
- Kind: B2
- Application number: 11/505,205
- Filed: 2006-08-16
- Published: 2007-02-22
- Granted: 2009-11-03
- Earliest claimed: 2005-08-17
- Assignees: Corning Incorporated
- Inventors: Bruce G. Aitken; Matthew J. Dejneka; Adam J. G. Ellison; Thomas E. Paulson
- Web page: https://patentgrep.com/patent/US7612004B2

## CPC

- C03C 3/095: containing rare earths
- 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

## Abstract

A family of glasses from the rare earth alumino-silicate (RE2O3—Al2O3—SiO2) ternary system exhibiting high strain point and low liquidus temperatures; preferably the La2O3—Al2O3—SiO2 ternary system. The glasses are excellent candidates for electronics applications and have the following composition, expressed in mole percent and calculated from the glass batch on an oxide basis: 60-85% SiO2, 10-25% Al2O3, and 4-15% RE2O3.

## Claims

### Claim 1

A substrate for a flat panel display device comprising a rare earth aluminosilicate glass exhibiting a strain point greater than approximately 650° C., a liquidus temperature less than approximately 1300° C., the glass comprising the following composition when calculated in mole percent and calculated from the batch on an oxide basis:
60-75%SiO2
10.6-20% Al2O3
2-15%RE2O3
the RE being a rare earth selected from group consisting of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and mixtures thereof; and
1-12% of one or more RO, wherein R is an alkaline earth metal selected from the group consisting of Mg, Ca, Sr, or any combination thereof; or when R is Ba, at least one additional alkaline earth metal selected from the group consisting of Mg, Ca, and Sr is present;
0-9% B2O3; and
0-2% SnO2,
wherein the composition does not contain TiO2 and Ta2O5 either individually or in any combination thereof.

### Claim 2 (depends on 1)

The substrate of claim 1 wherein said substrate comprises the following composition when calculated in mole percent and calculated from the batch on an oxide basis:
65-75% SiO2
10.6-20% Al2O3
4-15% RE2O3.

### Claim 3 (depends on 1)

The substrate of claim 1 having a strain point of at least 650° C.

### Claim 4 (depends on 1)

The substrate of claim 1 wherein the substrate comprises, in mole percent and calculated from the batch on an oxide basis, 2-15% La2O3.

### Claim 5 (depends on 1)

The substrate of claim 1 having a liquidus temperature of no greater than 1300° C.

### Claim 6 (depends on 1)

The substrate of claim 1 having a liquidus viscosity greater than 10,000 poise.

### Claim 7

A rare earth aluminosilicate glass exhibiting a strain point greater than approximately 650° C., a liquidus temperature less than approximately 1300° C., the glass comprising the following composition as calculated in a mole percent on an oxide basis:
65-75% SiO2
10.6-20% Al2O3
2-15% RE2O3
the RE being a rare earth selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof; and
1-12% of one or more RO, wherein R is an alkaline earth metal selected from the group consisting of Mg, Ca, r, or any combination thereof; or when R is Ba, at least one additional alkaline earth metal selected from the group consisting of Mg, Ca, and Sr is presented;
0-9% B2O3; and
0-2% SnO2,
wherein the composition does not contain TiO2 and Ta2O5 either individually or in any combination thereof.

### Claim 8 (depends on 7)

The glass of claim 7 further exhibiting a liquidus viscosity of greater than 10,000 poise.

### Claim 9 (depends on 7)

The glass of claim 7 further exhibiting a 200 Poise temperature that is less than 1550° C.

### Claim 10 (depends on 7)

The glass of claim 7, wherein the glass is a substrate present in an electronic device.

### Claim 11 (depends on 10)

The glass of claim 10 wherein the electronic device is an LCD display.

### Claim 12 (depends on 7)

The glass of claim 7, wherein Re is La.

### Claim 13 (depends on 7)

The glass of claim 7, wherein RE is La, and the amount of La2O3 is from 2-12.49% in mole percent as calculated from the batch on an oxide basis.

### Claim 14 (depends on 7)

The glass of claim 7, wherein the amount of RO is about 7-12% mole percent as calculated from the batch on an oxide basis.

### Claim 15 (depends on 7)

The glass of claim 7, wherein the amount of RO is about 10-12% mole percent as calculated from the batch on an oxide basis.

### Claim 16 (depends on 7)

The glass of claim 7, wherein the amount of B2O3 is about 0-3% mole percent as calculated from the batch on an oxide basis.

### Claim 17 (depends on 7)

The glass of claim 7, wherein the glass has a coefficient of thermal expansion (0-300° C.) of 25-50×10−7/° C.

### Claim 18 (depends on 7)

The glass of claim 7, wherein the glass has liquidus temperature less than 1250° C.

### Claim 19 (depends on 7)

The glass of claim 7, further comprising a ratio (RO+1.5*RE2O3)/Al2O3 wherein the ratio is between 0.85 and 1.2.

### Claim 20

A rare earth aluminosilicate glass exhibiting a strain point greater than approximately 650° C., a liquidus temperature less than approximately 1300° C., the glass consisting of the following composition as calculated in a mole percent on an oxide basis:
60-75% SiO2
10-20% Al2O3
2-12.49% RE2O3
the RE being a rare earth selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof; and
1-12% of one or more RO, wherein R is an alkaline earth metal selected from the group consisting of Mg, Ca, and Sr; or when R is Ba, at least one additional alkaline earth metal, selected from the group consisting of Mg, Ca, and Sr is present;
0-9% B2O3; and
0-2% SnO2.

### Claim 21 (depends on 20)

The glass of claim 20, wherein the glass is a substrate present in an electronic device.

### Claim 22 (depends on 21)

The glass of claim 21, wherein the electronic device is an LCD display.

### Claim 23 (depends on 20)

The lass of claim 20, further comprising a 200 Poise temperature that is less than 1550° C.