Alkali-free aluminoborosilicate glasses, and uses thereof

1. A glass comprising:

a substantially alkali-free aluminoborosilicate glass;

said glass having the composition (in % by weight, based on oxide):

SiO 2

>58–65 

B 2 O 3

  >6–11.5

Al 2 O 3

>14–25 

MgO

4–8

CaO

0–8

SrO

2.6–<4 

BaO

  0–<0.5

with SrO + BaO

>3

ZnO

0–2;

said composition of said SiO 2 , said B 2 O 3 , said Al 2 O 3 , said MgO, said CaO, said SrO, said BaO, said SrO+BaO, and said ZnO being selected to provide all of (i.), (ii.), (iii.), and (iv.), wherein (i.), (ii.), (iii.), and (iv.) comprise:

(i.) a coefficient of thermal expansion α 20/300 of between 2.8×10 −6 /K and 3.8×10 −6 /K;

(ii.) a glass transition temperature, T g , of more than 700 degrees Celsius to maximize heat resistance of said glass;

(iii.) a temperature at a viscosity of 10 2 dPas of at most 1694 degrees Celsius; and

(iv.) a processing temperature, V A , at a viscosity of 10 4 dPas of at most 1273 degrees Celsius.

2. The glass according to claim 1 , wherein said glass comprises one of (a.), (b.), and (c.):

(a.) more than 18% by weight of Al 2 O 3 ;

(b.) at least 20.5% by weight of Al 2 O 3 ; and

(c.) at least 21% by weight of Al 2 O 3 .

3. The glass according to claim 2 , wherein said glass comprises more than 8% by weight of B 2 O 3 .

4. The glass according to claim 3 , wherein said glass additionally comprises (in % by weight):

ZrO 2

0–2

TiO 2

0–2

with ZrO 2 + TiO 2

0–2

As 2 O 3

0–1.5

Sb 2 O 3

0–1.5

SnO 2

0–1.5

CeO 2

0–1.5

Cl −

0–1.5

F −

0–1.5

SO 4 2−

0–1.5

with As 2 O 3 + Sb 2 O 3 + SnO 2 + CeO 2 + Cl − + F − + SO 4 2−

0–1.5.

5. The glass according to claim 4 , wherein:

said glass is free of arsenic oxide and antimony oxide, apart from unavoidable impurities; and

said glass comprises a float glass.

6. The glass according to claim 5 , wherein said glass has a coefficient of thermal expansion α 20/300 of between 2.8×10 −6 /K and 3.6×10 −6 /K and a density, ρ, of <2.600 g/cm 3 .

7. The glass according to claim 6 , wherein said glass comprises a glass substrate for one of display technology and thin-film photovoltaics.

8. A glass comprising:

a substantially alkali-free aluminoborosilicate glass;

said glass having the composition (in % by weight, based on oxide):

SiO 2

>58–65 

B 2 O 3

  >6–11.5

Al 2 O 3

>14–25 

MgO

4–8

CaO

 0–<2

SrO

>0.5–<4  

BaO

  0–<0.5

ZnO

 0–2;

said composition of said SiO 2 , said B 2 O 3 , said Al 2 O 3 , said MgO, said CaO, said SrO, said BaO, and said ZnO being selected to provide all of (i.), (ii.), (iii.), and (iv.), wherein (i.), (ii.), (iii.), and (iv.) comprise:

(i.) a coefficient of thermal expansion α 20/300 of between 2.8×10 −6 /K and 3.4×10 −6 /K;

(ii.) a glass transition temperature, T g , of more than 700 degrees Celsius to maximize heat resistance of said glass;

(iii.) a temperature at a viscosity of 10 2 dPas of at most 1694 degrees Celsius; and

(iv.) a processing temperature, V A , at a viscosity of 10 4 dPas of at most 1273 degrees Celsius.

9. The glass according to claim 8 , wherein said glass comprises one of (a.), (b.), and (c.):

(a.) more than 18% by weight of Al 2 O 3 ;

(b.) at least 20.5% by weight of Al 2 O 3 ; and

(c.) at least 21% by weight of Al 2 O 3 .

10. The glass according to claim 9 , wherein said glass comprises more than 8% by weight of B 2 O 3 .

11. The glass according to claim 10 , wherein said glass additionally comprises (in % by weight):

ZrO 2

0–2

TiO 2

0–2

with ZrO 2 + TiO 2

0–2

As 2 O 3

0–1.5

Sb 2 O 3

0–1.5

SnO 2

0–1.5

CeO 2

0–1.5

Cl −

0–1.5

F −

0–1.5

SO 4 2−

0–1.5

with As 2 O 3 + Sb 2 O 3 + SnO 2 + CeO 2 + Cl − + F − + SO 4 2−

0–1.5.

12. The glass according to claim 11 , wherein:

said glass is free of arsenic oxide and antimony oxide, apart from unavoidable impurities; and

said glass comprises a float glass.

13. The glass according to claim 12 , wherein said glass has a coefficient of thermal expansion α 20/300 of between 2.8×10 −6 /K and 3.6×10 −6 /K and a density, ρ, of <2.600 g/cm 3 .

14. The glass according to claim 13 , wherein said glass comprises a glass substrate for one of display technology and thin-film photovoltaics.

15. A glass comprising:

a substantially alkali-free aluminoborosilicate glass;

said glass having the composition (in % by weight, based on oxide):

SiO 2

>58–65 

B 2 O 3

  >6–11.5

Al 2 O 3

>21–25 

MgO

4–8

CaO

0–8

SrO

2.6–<8 

BaO

  0–<0.5

with SrO + BaO

>3

ZnO

 0–2;

said composition of said SiO 2 , said B 2 O 3 , said Al 2 O 3 , said MgO, said CaO, said SrO, said BaO, said SrO+BaO, and said ZnO being selected to provide all of (i.), (ii.), (iii.), and (iv.), wherein (i.), (ii.), (iii.), and (iv.) comprise:

(i.) a coefficient of thermal expansion α 20/300 of between 2.8×10 −6 /K and 3.6×10 −6 /K;

(ii.) a glass transition temperature, T g , of more than 700 degrees Celsius to maximize heat resistance of said glass;

(iii.) a temperature at a viscosity of 10 2 dPas of at most 1694 degrees Celsius; and

(iv.) a processing temperature, V A , at a viscosity of 10 4 dPas of at most 1273 degrees Celsius.

16. The glass according to claim 15 , wherein said glass comprises more than 8% by weight of B 2 O 3 .

17. The glass according to claim 16 , wherein said glass additionally comprises (in % by weight):

ZrO 2

0–2  

TiO 2

0–2  

with ZrO 2 + TiO 2

0–2  

As 2 O 3

0–1.5

Sb 2 O 3

0–1.5

SnO 2

0–1.5

CeO 2

0–1.5

Cl −

0–1.5

F −

0–1.5

SO 4 2−

0–1.5

with As 2 O 3 + Sb 2 O 3 + SnO 2 + CeO 2 + Cl − + F − + SO 4 2−

0–1.5.

18. The glass according to claim 17 , wherein:

said glass is free of arsenic oxide and antimony oxide, apart from unavoidable impurities; and

said glass comprises a float glass.

19. The glass according to claim 18 , wherein said glass has a coefficient of thermal expansion α 20/300 of between 2.8×10 −6 /K and 3.6×10 −6 /K and a density, ρ, of <2.600 g/cm 3 .

20. The glass according to claim 19 , wherein said glass comprises a glass substrate for one of display technology and thin-film photovoltaics.