Glass sheet having high transmission of infrared radiation

Abstract

The invention relates to a glass sheet having high transmission of infrared (IR) radiation. More specifically, the invention relates to a glass sheet having a composition which comprises, in a content expressed as percentages by total weight of glass: SiO.sub.2 55-85% AI.sub.2O.sub.3 0-30% B.sub.2O.sub.3 0-20% Na.sub.2O 0-25% CaO 0-20% MgO 0-15% K.sub.2O 0-20% BaO 0-20% total iron (expressed in the form of Fe.sub.2O.sub.3) 0.002-1%, Cr.sub.2O.sub.3 0.001-0.5% Co 0.0001-0.5% Se 0.0003-0.5%. By virtue of its high transmission of IR radiation, said glass sheet can advantageously be used in a device using a technology requiring very good transmission of IR radiation, whether through the main faces or starting from their edge (for example, a screen or panel or pad) The invention thus also relates to the use of such a glass sheet in a device using infrared radiation propagating essentially inside said sheet.

Claims

1. A glass sheet having a composition which comprises, in a content expressed as percentages by total weight of glass: SiO.sub.2: 55-85%, Al.sub.2O.sub.3: 0-30%, B.sub.7O.sub.3: 0-20%, Na.sub.2O: 0-25%, CaO: 0-20%, MgO: 0-15%, K.sub.2O: 0-20%, BaO: 0-20%, total iron, expressed in the form of Fe.sub.2O.sub.3: 0.002-1%, chromium, expressed in the form of Cr.sub.2O.sub.3: 0.001% to 0.5%, cobalt, expressed in the form of Co: 0.0001% to 0.5%, and selenium, expressed in the form of Se: 0.0003% to 0.5%, wherein the sheet has: TIR4>TLD4; TIR4 being an IR transmission for a wavelength range between 780 and 2500 nm and TLD4 being a light transmission with illuminant D65 at a solid observation angle of 2 for a wavelength range between 380 and 780 nm; each being in % and according to the ISO 9050 standard for a sheet thickness of 4 mm, and wherein the composition comprises an Fe.sup.2+ content (expressed in the form of FeO) of less than 20 ppm.

2. The glass sheet according to claim 1, wherein the composition comprises a total iron content such that: 0.002Fe.sub.2O.sub.30.3%.

3. The glass sheet according to claim 1, wherein the composition comprises a total iron content such that: 0.002Fe.sub.2O.sub.30.06%.

4. The glass sheet according to claim 1, wherein the composition comprises a total iron content such that: 0.002Fe.sub.2O.sub.30.04%.

5. The glass sheet according to claim 1, wherein Fe.sub.2O.sub.37*Cr.sub.2O.sub.3.

6. The glass sheet according to claim 1, wherein the composition comprises: a total iron content, expressed in the form of Fe.sub.2O.sub.3, 0.7%; a chromium content, expressed in the form of Cr.sub.2O.sub.3, 0.0465%; a cobalt content, expressed in the form of Co, 0.004%; wherein:
(Se*Fe.sub.2O.sub.3)0.0012%; and
(3000*Co)+(260*Cr.sub.2O.sub.3)+(10000*Se*Fe.sub.2O.sub.3)+(16.2*Fe.sub.2O.sub.3)<12.

7. The glass sheet according to claim 1, wherein the composition comprises: a total iron content, expressed in the form of Fe.sub.2O.sub.3, 0.4%; a chromium content, expressed in the form of Cr.sub.2O.sub.3, 0.027%; a cobalt content, expressed in the form of Co, 0.0023%; wherein:
(Se*Fe.sub.2O.sub.3)0.0007%; and
(3000*Co)+(260*Cr.sub.2O.sub.3)+(10000*Se*Fe.sub.2O.sub.3)+(16.2*Fe.sub.2O.sub.3)<7.

8. The glass sheet according to claim 1, wherein the composition comprises: a total iron content, expressed in the form of Fe.sub.2O.sub.3, 0.2%; a chromium content, expressed in the form of Cr.sub.2O.sub.3, 0.011%; a cobalt content, expressed in the form of Co, 0.001%; wherein:
(Se*Fe.sub.2O.sub.3)0.0003%; and
(3000*Co)+(260*Cr.sub.2O.sub.3)+(10000*Se*Fe.sub.2O.sub.3)+(16.2*Fe.sub.2O.sub.3)<3.

9. The glass sheet according to claim 1, wherein: (3000*C)+(260*Cr.sub.2O.sub.3)+(10000*Se*Fe.sub.2O.sub.3)+(16.2*Fe.sub.2O.sub.3)12.

10. The glass sheet according to claim 9, wherein: 1*Co<Se<10*Co.

11. The glass sheet according to claim 9, wherein: 2*Co<Se<17*Co.

12. The glass sheet according to claim 9, wherein: 1*Co<Cr.sub.2O.sub.3<10*Co.

13. The glass sheet according to claim 9, wherein: 2*Co<Cr.sub.2O.sub.3<10*Co.

14. The glass sheet according to claim 1, wherein the composition comprises a TLD4>80%.

15. A touch screen or touch panel or touchpad, comprising at least one glass sheet according to claim 1 as a touch surface.

16. A glass sheet having a composition which comprises, in a content expressed as percentages by total weight of glass: SiO.sub.2: 60-75%, Al.sub.2O.sub.3: 0-6%, B.sub.2O.sub.3: 0-4%, Na.sub.2O: 5-20%, CaO: 0-15%, MgO: 0-10%, K.sub.2O: 0-10%, BaO: 0-5%, total iron, expressed in the form of Fe.sub.2O.sub.3: 0.002-1%, chromium, expressed in the form of Cr.sub.2O.sub.3: 0.001% to 0.5%, cobalt, expressed in the form of Co: 0.0001% to 0.5%, and selenium, expressed in the form of Se: 0.0003% to 0.5%, wherein the sheet has: TIR4>TLD4; TIR4 being an IR transmission for a wavelength range between 780 and 2500 nm and TLD4 being a light transmission with illuminant D65 at a solid observation angle of 2 for a wavelength range between 380 and 780 nm; each being in % and according to the ISO 9050 standard for a sheet thickness of 4 mm, wherein the composition comprises an Fe.sup.2+ content (expressed in the form of FeO) of less than 20 ppm.

17. The glass sheet according to claim 6, wherein Fe.sub.2O.sub.37*Cr.sub.2O.sub.3.

18. The glass sheet according to claim 16, wherein hre composition comprises: a total iron content, expressed in the form of Fe.sub.2O.sub.3, 0.7%; a chromium content, expressed in the form of Cr.sub.2O.sub.3, 0.0465%; a cobalt content, expressed in the form of Co, 0.004%; wherein:
(Se*Fe.sub.2O.sub.3)0.0012%; and
(3000*Co)+(260*Cr.sub.2O.sub.3)+(10000*Se*Fe.sub.2O.sub.3)+(16.2*Fe.sub.2O.sub.3)<12.

19. The glass sheet according to claim 16, wherein the composition comprises a TLD4>80%.

20. A touch screen or touch panel or touchpad, comprising at least one glass sheet according to claim 16 as a touch surface.

Description

EXAMPLES

(1) Various glass sheets according to the invention were prepared or calculated/simulated, in the form of 5 sets, with variable amounts of total iron, chromium, cobalt and selenium and/or nickel.

(2) For the preparation of the glass sheets according to the invention: the starting materials were mixed in the powder form and placed in a crucible for the melting, according to an identical base composition specified in the table below, and to which were added starting materials comprising iron, chromium, cobalt and selenium and/or nickel in variable amounts as a function of the contents targeted in the final composition (it should be noted that the iron is already, at least in part, present in the starting materials of the base composition as impurity).

(3) TABLE-US-00003 Base composition Content [% by weight] SiO.sub.2 71.71 CaO 8.24 K.sub.2O 0.02 Na.sub.2O 14.20 SO.sub.3 0.33 Al.sub.2O.sub.3 1.0 MgO 4.50

(4) The optical properties of each composition prepared by melting, in sheet form, were determined on a Perkin Elmer Lambda 950 spectrophotometer equipped with an integrating sphere with a diameter of 150 mm, and in particular: the transmission TIR4 was determined according to the ISO 9050 standard for a thickness of 4 mm and for a wavelength range between 780 and 2500 nm; the light transmission TLD4 was also determined according to the ISO 9050 standard for a thickness of 4 mm at a solid observation angle of 2 (illuminant D65) and for a wavelength range between 380 and 780 nm; the CIE L*a*b* parameters were determined in transmission with the following measurement parameters: illuminant D65, 10, thickness 5 mm.

(5) For the simulation of the glass compositions according to the invention: the optical properties of various glass sheets were calculated on the basis of the optical properties of the various colourants (coefficients of absorption given by Bamford's theory).

(6) The glass sheets from Examples 12 and 13 were prepared by melting and their optical properties were measured. The same optical properties were also measured for commercial glass sheets, as comparative examples (Examples 3, 6, 9, 11 and 14).

(7) The optical properties of Examples 1, 2, 4, 5, 7, 8 and 10 are derived from simulation/calculations.

(8) Set 1

(9) Examples 1 and 2 correspond to glass sheets according to the invention. Example 3 (comparative example) corresponds to a coloured glass from the prior art having a high iron content (grey glass sold under the name Planibel Grey). Each Example 1-2 of composition according to the invention was optimized so as to achieve values of the colorimetric parameters (a*b*) and of the light transmission (TLD4) that are similar to the grey glass of the comparative example (glass offered on the market), but while maximizing the transmission of infrared radiation (TIR4).

(10) Table 1 presents the optical properties calculated for Examples 1 and 2 and measured for Comparative Example 3, and also their respective amounts of iron, chromium, cobalt, selenium and nickel.

(11) FIG. 1(a) represents the curves in transmission for one and the same glass thickness between the wavelengths 290 and 2500 nm (thus including the visible and near infrared regions) of Examples 1 and 2 according to the invention and of Example 3 according to the prior art (Planibel Grey grey glass). FIG. 1(b) represents an enlargement of FIG. 1(a) between the wavelengths 400 and 1250 nm.

(12) TABLE-US-00004 TABLE 1 Colorimetric Fe.sub.2O.sub.3 Cr.sub.2O.sub.3 Co Se Ni 850 nm 950 nm 1050 nm TLD4 TIR4 parameters ppm ppm ppm ppm ppm (m.sup.1) (m.sup.1) (m.sup.1) (%) (%) L* a* b* 1 431 288 70 200 0 4.2 4.6 5.3 55.9 89.9 75.6 1.6 2.3 2 200 133 68 468 56 7.5 8.0 2.9 55.7 89.9 75.5 1 2.4 3 3710 17 62 19 0 130.6 153.1 163.3 54.5 54.4 74.7 0.6 1.9

(13) The results obtained (see FIG. 1 and Table 1) show that the addition of chromium, cobalt and selenium and/or nickel in a content range according to the invention (second main embodiment) in combination with a low iron content makes it possible to obtain a glass sheet with a T.sub.L and a colour that are highly comparable to a commercial grey glass, while very significantly increasing the transmission in the infrared region (highly increased TIR4 or very low ).

(14) Set 2

(15) Examples 4 and 5 correspond to glass sheets according to the invention. Example 6 (comparative example) corresponds to a coloured glass from the prior art having a high iron content (dark grey glass sold under the name Planibel Dark Grey). Each Example 4-5 of composition according to the invention was optimized so as to achieve values of the colorimetric parameters (a*b*) and of the light transmission (TLD4) that are similar to the dark grey glass of Comparative Example 6 (glass offered on the market), but while maximizing the transmission of infrared radiation (TIR4).

(16) Table 2 presents the optical properties calculated for Examples 4 and 5 and measured for Example 6, and also their respective amounts of iron, chromium, cobalt, selenium and nickel.

(17) FIG. 2(a) represents the curves in transmission for one and the same glass thickness between the wavelengths 290 and 2500 nm (thus including the visible and near infrared regions) of Examples 4 and 5 according to the invention and of Example 6 according to the prior art (Planibel Dark Grey dark grey glass). FIG. 2(b) represents an enlargement of FIG. 2(a) between the wavelengths 400 and 1250 nm.

(18) TABLE-US-00005 TABLE 2 Colorimetric Fe.sub.2O.sub.3 Cr.sub.2O.sub.3 Co Se Ni 850 nm 950 nm 1050 nm TLD4 TIR4 parameters ppm ppm ppm ppm ppm (m.sup.1) (m.sup.1) (m.sup.1) (%) (%) L* a* b* 4 670 800 215 560 0 12.8 14.2 16.0 17.2 86 40 1.3 1 5 690 460 204 256 656 53.0 55.8 57.7 17.4 73.4 40.3 1.2 0.1 6 11460 68 177 37 0 451.5 533.1 568.1 17.3 16.5 40.2 0.1 0.5

(19) The results obtained (see FIG. 2 and Table 2) show that the addition of chromium, cobalt and selenium and/or nickel in a content range according to the invention (second main embodiment) in combination with a relatively low iron content makes it possible to obtain a dark grey glass sheet that is highly comparable in terms of colour and T.sub.L to a dark grey glass from the prior art, while very significantly increasing the transmission in the infrared region (highly increased TIR4 or very low ).

(20) Set 3

(21) Examples 7 and 8 correspond to glass sheets according to the invention. Example 9 (comparative example) corresponds to a coloured glass from the prior art having a high iron content (bronze glass sold under the name Planibel Bronze). Each Example 7 and 8 of composition according to the invention was optimized so as to achieve values of the colorimetric parameters (a*b*) and of the light transmission (TLD4) that are similar to the bronze glass of Comparative Example 9 (glass offered on the market), but while maximizing the transmission of infrared radiation (TIR4).

(22) Table 3 presents the optical properties calculated for Examples 7 and 8 and measured for Comparative Example 9, and also their respective amounts of iron, chromium, cobalt, selenium and nickel.

(23) FIG. 3(a) represents the curves in transmission for one and the same glass thickness between the wavelengths 290 and 2500 nm (thus including the visible and near infrared regions) of Examples 7 and 8 according to the invention and of Example 9 according to the prior art (Planibel Bronze Bronze glass). FIG. 3(b) represents an enlargement of FIG. 3(a) between the wavelengths 400 and 1250 nm.

(24) TABLE-US-00006 TABLE 3 Colorimetric Fe.sub.2O.sub.3 Cr.sub.2O.sub.3 Co Se Ni 850 nm 950 nm 1050 nm TLD4 TIR4 parameters ppm ppm ppm ppm ppm (m.sup.1) (m.sup.1) (m.sup.1) (%) (%) L* a* b* 7 400 200 45 341 0 2.7 3.0 3.4 57.9 90.5 76.7 3.1 5.2 8 206 137 38 566 41 4.8 5.1 2.9 60.9 90.4 78.7 3.3 5.3 9 3130 33 30 27 0 104.5 119.8 126.0 60.9 61.2 78.7 3.3 5.3

(25) The results obtained (see FIG. 3 and Table 3) show that the addition of chromium, cobalt and selenium and/or nickel in a content range according to the invention (second main embodiment) in combination with a low iron content makes it possible to obtain a bronze glass sheet that is highly comparable in terms of colour and T.sub.L to a commercial bronze glass, while very significantly increasing the transmission in the infrared region (highly increased TIR4 or very low ).

(26) Set 4

(27) Example 10 corresponds to a glass sheet according to the invention. Example 11 (comparative example) corresponds to a coloured glass from the prior art having a high iron content (light grey glass sold under the name Optigrey). Example 10 of composition according to the invention was optimized so as to achieve values of the colorimetric parameters (a*b*) and of the light transmission (TLD4) that are similar to the light grey glass of Comparative Example 10 (glass offered on the market), but while maximizing the transmission of infrared radiation (TIR4).

(28) Table 4 presents the optical properties calculated for Example 10 and measured for Example 11, and also their respective amounts of iron, chromium, cobalt and selenium.

(29) FIG. 4(a) represents the curves in transmission for one and the same glass thickness between the wavelengths 290 and 2500 nm (thus including the visible and near infrared regions) of Example 10 according to the invention and of Example 11 according to the prior art (Optigrey light grey glass). FIG. 4(b) represents an enlargement of FIG. 4(a) between the wavelengths 400 and 1250 nm.

(30) TABLE-US-00007 TABLE 4 Colorimetric Fe.sub.2O.sub.3 Cr.sub.2O.sub.3 Co Se 850 nm 950 nm 1050 nm TLD4 TIR4 parameters ppm ppm ppm ppm (m.sup.1) (m.sup.1) (m.sup.1) (%) (%) L* a* b* 10 750 111 36 74 2.1 2.4 2.9 70.1 90.8 84.7 0 0 11 3300 0 23 7 139.3 165.1 174.3 70.1 53 84.7 1.3 0.1

(31) The results obtained (see FIG. 4 and Table 4) show that the addition of chromium, cobalt and selenium in a content range according to the invention (second main embodiment) in combination with a low iron content makes it possible to obtain a light grey glass sheet that is highly comparable in terms of T.sub.L to a commercial light grey glass but that is aesthetically more neutral, while very significantly increasing the transmission in the infrared region (highly increased TIR4 or very low ).

(32) Set 5

(33) Examples 12 and 13 correspond to coloured glass sheets according to the invention. Example 14 (comparative example) corresponds to a conventional clear glass from the prior art (clear glass sold under the name Planibel clear).

(34) Table 5 presents the optical properties measured for Examples 12-14 and also their respective amounts of iron, chromium, cobalt and selenium.

(35) FIG. 5(a) represents the curves in transmission for one and the same glass thickness between the wavelengths 290 and 2500 nm (thus including the visible and near infrared regions) of Examples 12-13 according to the invention and of Example 14 according to the prior art (clear glass). FIG. 5(b) represents an enlargement of FIG. 5(a) between the wavelengths 400 and 1250 nm.

(36) TABLE-US-00008 TABLE 5 Colorimetric Fe.sub.2O.sub.3 Cr.sub.2O.sub.3 Co Se 850 nm 950 nm 1050 nm TLD4 TIR4 parameters ppm ppm ppm ppm (m.sup.1) (m.sup.1) (m.sup.1) (%) (%) L* a* b* 12 480 168 45 48 5.5 3.5 4.4 65.8 89.3 82.2 1.8 2.4 13 480 167 44 53 5.0 3.3 4.3 66.9 89.4 82.8 2.3 2.3 14 850 0 0 0 33.9 39.5 41.5 89.7 80.6 95.7 1.1 0.2

(37) The results obtained (see FIG. 5 and Table 5) show that the addition of chromium, cobalt and selenium in a content range according to the invention in combination with a low iron content makes it possible to obtain a coloured glass sheet (with a lower T.sub.L), while more than significantly increasing its transmission in the infrared region (with respect to the coloured glasses from the corresponding prior art, but also in comparison with a clear glass from the prior artEx. 14).

(38) Furthermore, Examples 12 and 13 according to the invention, coloured glass sheets, exhibit coefficients of absorption in the IR region which are lower than those of a clear glass from the prior art (Example 14).