Flat glass, method for producing same, and use thereof

Abstract

A flat glass is provided that exhibits high transmittance to electromagnetic radiation in a range of wavelengths from 200 nm to 1500 nm. The transmittance for the flat glass having a thickness of 1 mm is 20% or more at a wavelength of 254 nm, 82% or more at a wavelength of 300 nm, 90% or more at a wavelength of 350 nm, 92% or more at a wavelength of 546 nm, 92.5% or more at a wavelength of 1400 nm, 91.5% or more in a wavelength range from 380 nm to 780 nm, and 92.5% or more in a wavelength range from 780 nm to 1500 nm.

Claims

1. A flat glass comprising a transmittance to electromagnetic radiation for glass having a thickness of 1 mm that is 20% or more at a wavelength of 254 nm, 82% or more at a wavelength of 300 nm, 90% or more at a wavelength of 350 nm, 92% or more at a wavelength of 546 nm, 92.5% or more at a wavelength of 1400 nm, 91.5% or more in a wavelength range from 380 nm to 780 nm, and 92.5% or more in a wavelength range from 780 nm to 1500 nm, wherein the flat glass comprises B.sub.2O.sub.3, and wherein the flat glass further comprises a ratio of weight fractions of ions of iron that is 0.1≤Fe.sup.2+/(Fe.sup.2++Fe.sup.3+)≤0.3 and comprises a ratio of molar amounts Σ(Me.sub.xO.sub.y)/(Σ(SiO.sub.2+B.sub.2O.sub.3) between 0.02 to 0.10, wherein Me is selected from a group consisting of an alkali metal, an alkaline earth metal, and aluminum.

2. The flat glass of claim 1, wherein the transmittance is 60% or more at the wavelength of 254 nm, 90% or more at the wavelength of 300 nm, 91% or more at the wavelength of 350 nm, 92.5% or more at the wavelength of 546 nm, 93% or more at the wavelength of 1400 nm, 92% or more in the wavelength range from 380 nm to 780 nm, and 93% or more in the wavelength range from 780 nm to 1500 nm.

3. The flat glass of claim 2, wherein the transmittance is 85% or more at a wavelength of 254 nm and 91% or more at a wavelength of 300 nm.

4. The flat glass of claim 3, wherein the transmittance is 88% or more at a wavelength of 254 nm.

5. The flat glass of claim 1, further comprising a content of oxides of network formers of not more than 98 mol % in total.

6. The flat glass of claim 5, wherein the oxides of network formers comprise oxides of silicon and/or boron.

7. The flat glass of claim 1, further comprising a coefficient of linear thermal expansion between 2.4*10.sup.−6/K and 3.5*10.sup.−6/K.

8. The flat glass of claim 1, further comprising a content of SiO.sub.2 between 72 mol % and 85 mol %.

9. The flat glass of claim 1, further comprising a content of B.sub.2O.sub.3 between 10 mol % and 25 mol %.

10. The flat glass of claim 1, further comprising Σ(SiO.sub.2+B.sub.2O.sub.3) of 92 mol % to 98 mol %.

11. The flat glass of claim 1, further comprising ΣR.sub.2O that is between 1 mol % and 5 mol %, wherein R.sub.2O is alkali metal oxides.

12. The flat glass of claim 1, further comprising a ratio of molar amounts of B.sub.2O.sub.3/SiO.sub.2 between 0.12 to 0.35.

13. The flat glass of claim 1, wherein for the weight fractions, in ppm, of Fe, Co, Ni, Cr, Cu, Mn, and V, the following applies: Σ(1*Fe+300*Co+70*Ni+50*Cr+20*Cu+5*Mn+2*V) [ppm by mass] is less than 200 ppm, wherein a total content of considered metals is considered irrespective of an oxidation state thereof.

14. The flat glass of claim 1, further comprising a transformation temperature between 450° C. and 550° C.

15. The flat glass of claim 1, further comprising having a viscosity η, wherein Ig η has a value of 4 at temperatures between 1000° C. and 1320° C.

16. The flat glass of claim 1, further comprising a refractive index at a light wavelength of 587.6 nm that is less than 1.475.

17. The flat glass of claim 1, further comprising a value of chemical resistance against water according to DIN ISO 719 class HGB 1, a value of chemical resistance against acids according to DIN 12116 class S 1 W; and a value of chemical resistance against alkalis according to DIN ISO 695 class A3 or better.

18. The flat glass of claim 1, comprising: TABLE-US-00013 SiO.sub.2 72 mol % to 85 mol %, B.sub.2O.sub.3 10 mol % to 25 mol %, Al.sub.2O.sub.3 0.2 mol % to 2.5 mol %, Na.sub.2O 0.5 mol % to 5.0 mol %, K.sub.2O 0 mol % to 1.0 mol %, and Li.sub.2O 0 mol % to 1.5 mol %.

19. The flat glass of claim 18, wherein the Na.sub.2O, K.sub.2O, Li.sub.2O amount to less than 5 mol % in total.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows curves of spectral transmittance for electromagnetic radiation in the wavelength range from 200 nm to 1500 nm for flat glass according to the invention;

(2) FIG. 2 shows a further transmittance spectrum in the wavelength range from 200 nm to 800 nm for the exemplary glass 8 in comparison with selected comparative glasses; and

(3) FIG. 3 is a schematic view of a flat glass, not drawn to scale.

DETAILED DESCRIPTION

(4) FIG. 1 shows curves of spectral transmittance of different flat glasses for a thickness of 1 mm according to different embodiments.

(5) Transmittance curve 1 was obtained for a flat glass with a composition corresponding to glass 5 from Table 1.

(6) Transmittance curve 2 was obtained for a flat glass with a composition corresponding to glass 4 from Table 1.

(7) Transmittance curve 3 was obtained for a flat glass with a composition corresponding to glass 8 from Table 1.

(8) Transmittance curve 4 was obtained for a flat glass with a composition corresponding to glass 3 from Table 1.

(9) Transmittance curve 5 was obtained for a flat glass with a composition corresponding to glass 2 from Table 1.

(10) FIG. 2 shows a further transmittance spectrum of a flat glass for a thickness of 1 mm according to one embodiment in comparison to transmittance spectra that were obtained for selected comparative glasses, again for a thickness of 1 mm. Here, the wavelength range from 200 nm to 800 nm is considered.

(11) Transmittance curve 6 was obtained for a flat glass with a composition corresponding to glass 8 from Table 1.

(12) Transmittance curve 7 was obtained for a glass of 1 mm thickness with a composition corresponding to glass B from Table 2.

(13) Transmittance curve 8 was obtained for a glass of 1 mm thickness with a composition corresponding to glass F from Table 2.

(14) Transmittance curve 9 was obtained for a glass of 1 mm thickness with a composition corresponding to glass D from Table 2.

(15) Transmittance curve 10 was obtained for a glass of 1 mm thickness with a composition corresponding to glass I from Table 2.

(16) Transmittance curve 11 was obtained for a glass of 1 mm thickness with a composition corresponding to glass E from Table 2.

(17) It can clearly be seen that the flat glass according to an embodiment of the invention exhibits increased transmittance within the entire illustrated wavelength range, in comparison to the prior art glasses.

(18) FIG. 3 is a schematic view of a flat glass 100, not drawn to scale. Flat glass 100 comprises two surfaces 101 and 102. In the context of the present invention, the two principal surfaces of the glass body are referred to as the surfaces 101, 102 of the flat glass 100, i.e. those surfaces which are defined by the length and the width of the glass body.

(19) The flat glass 100 exhibits transmittance for electromagnetic radiation, in particular in the wavelength range from 200 nm to 1500 nm, and at a thickness of the flat glass of 1 mm the flat glass exhibits a transmittance to electromagnetic radiation which is 20% or more, preferably 60% or more, more preferably 85% or more, and most preferably 88% or more at a wavelength of 254 nm; and/or which preferably is 82% or more, preferably 90% or more, more preferably 91% or more at a wavelength of 300 nm; and/or which preferably is 90% or more, preferably 91% or more at a wavelength of 350 nm; and/or which preferably is 92% or more, preferably 92.5% or more at a wavelength of 546 nm; and/or which preferably is 92.5% or more, preferably 93% or more at a wavelength of 1400 nm; and/or which is 91.5% or more, preferably 92% or more in a wavelength range from 380 nm to 780 nm; and/or which preferably is 92.5% or more, preferably 93% or more in a wavelength range from 780 nm to 1500 nm.

(20) According to a preferred embodiment, the flat glass 100 comprises a content of oxides of network formers, in particular of oxides of silicon and/or boron, of not more than 98 mol % in total.

(21) Preferably, the flat glass 100 has a coefficient of linear thermal expansion or between 2.4*10.sup.−6/K and 3.5*10.sup.−6/K.

(22) According to one embodiment, the flat glass 100 has a content of SiO.sub.2 between 72 mol % and 85 mol %, preferably between 76 mol % and 85 mol %.

(23) According to a further embodiment, the flat glass 100 comprises B.sub.2O.sub.3, wherein preferably the content of B.sub.2O.sub.3 in the flat glass is between 10 mol % and 25 mol %, most preferably between 10 mol % and 22 mol %.

(24) The flat glass 100 preferably comprises SiO.sub.2 and B.sub.2O.sub.3, wherein preferably Σ(SiO.sub.2+B.sub.2O.sub.3) is 92 mol % to 98 mol %.

(25) According to another embodiment of the flat glass 100, ΣR.sub.2O is between 1 mol % and 5 mol %, wherein R.sub.2O stands for alkali metal oxides.

(26) With regard to the ratio of molar amounts of the components of the flat glass 100, preferably the following applies:

(27) TABLE-US-00011 B.sub.2O.sub.3/SiO.sub.2 0.12 to 0.35; and/or Σ(Me.sub.xO.sub.y)/(Σ(SiO.sub.2 + B.sub.2O.sub.3) 0.02 to 0.10;

(28) wherein Me represents a metal which usually has the oxidation number y in oxides, in particular one of an alkali metal and/or alkaline earth metal, and aluminum.

(29) According to yet another embodiment of the flat glass 100, the following applies to the ratio of weight fractions of the iron ions contained in the flat glass:
≤Fe.sup.2+/(Fe.sup.2++Fe.sup.3+)≤0.3.

(30) In accordance with yet another embodiment of the flat glass 100, the following applies to the metals Fe, Co, Ni, Cr, Cu, Mn, V contained in the flat glass 100 with regard to the weight fractions thereof, in ppm:
Σ(1*Fe+300*Co+70*Ni+50*Cr+20*Cu+5*Mn+2*V)[ppm by mass]

(31) is less than 200 ppm, preferably less than 150 ppm, more preferably less than 100 ppm, yet more preferably less than 50 ppm, and most preferably less than 25 ppm;

(32) wherein the total content of the considered metals in the flat glass 100 is considered irrespective of their oxidation state.

(33) Preferably, the transformation temperature T.sub.g of the flat glass 100 is between 450° C. and 550° C.

(34) According to one embodiment of the flat glass 100, it has a viscosity η, and Ig η has a value of 4 at temperatures between 1000° C. and 1320° C.

(35) According to yet another embodiment of the flat glass 100, the refractive index n.sub.d of the flat glass 100 at a light wavelength of 587.6 nm is less than 1.475.

(36) The flat glass 100 is preferably distinguished by values of chemical resistance

(37) against water according to DIN ISO 719 class HGB 1;

(38) against acids according to DIN 12116 class S 1 W; and

(39) against alkalis according to DIN ISO 695 class A3 or better.

(40) According to another embodiment, the flat glass 100 comprises the following constituents:

(41) TABLE-US-00012 SiO.sub.2 72 mol % to 85 mol %, preferably 76 mol % to 85 mol %, B.sub.2O.sub.3 10 mol % to 25 mol %, preferably 10 mol % to 22 mol %, Al.sub.2O.sub.3 0.2 mol % to 2.5 mol %, Na.sub.2O 0.5 mol % to 5.0 mol %, K.sub.2O 0 mol % to 1.0 mol %, Li.sub.2O 0 mol % to 1.5 mol %,

(42) wherein, preferably, the alkali metal oxides Na.sub.2O, K.sub.2O, Li.sub.2O contained in the flat glass 100, preferably all alkali metal oxides contained in the flat glass 100, amount to less than 5 mol % in total.

(43) According to one embodiment, the flat glass 100 is produced or producible by a melting process with subsequent hot forming, in particular in a float process, a rolling process, or a drawing process such as a down-draw process, preferably an overflow fusion down-draw process, or an up-draw process, or a Foucault process.