초록 ▼

The present invention provides a glass sheet formed on molten tin, that exhibits a high transmittance that is originally inherent to its composition. In this glass sheet, the difference between a visible light reflectance of a surface formed in contact with the molten tin and a visible light reflect

The present invention provides a glass sheet formed on molten tin, that exhibits a high transmittance that is originally inherent to its composition. In this glass sheet, the difference between a visible light reflectance of a surface formed in contact with the molten tin and a visible light reflectance of a surface on the opposite side thereof is not greater than 0.25%. And when the glass sheet's thickness is 4 mm, a light transmittance at 540 nm wavelength is at least 91.5%, and a light transmittance at 450 nm wavelength is at least 91.0%, and after irradiating UV light for 6 hours as specified in the radiation-proofing test according to JIS R3212, a light transmittance at 540 nm wavelength is at least 91.0% and a light transmittance at 450 nm wavelength is at least 90.5%.

대표청구항 ▼

The invention claimed is: 1. A glass sheet formed on molten tin, wherein a difference between a visible light reflectance of a surface formed in contact with the molten tin and a visible light reflectance of a surface on the opposite side thereof is not greater than 0.25%; wherein, when the glass s

The invention claimed is: 1. A glass sheet formed on molten tin, wherein a difference between a visible light reflectance of a surface formed in contact with the molten tin and a visible light reflectance of a surface on the opposite side thereof is not greater than 0.25%; wherein, when the glass sheet's thickness is 4 mm, a light transmittance at 540 nm wavelength is at least 91.5%, and a light transmittance of at 450 nm wavelength is at least 91.0%, and wherein after irradiating UV light for 6 hours as specified in the radiation-proofing test according to Japanese Industrial Standard (JIS) R3212, a light transmittance at 540 nm wavelength is at least 91.0% and a light transmittance at 450 nm wavelength is at least 90.5%; wherein a maximum value of tin oxide concentration in terms of SnO2, in the glass sheet at a depth of up to 10 μm from the surface formed in contact with the molten tin, measured by a wavelength dispersive X-ray detector (WDX) mounted to an electron probe micro-analyzer (EPMA), is not greater than 1 mass %; and wherein a maximum value of iron oxide concentration in terms of Fe2O3, in the glass sheet at a depth of up to 5 μ m from the surface formed in contact with the molten tin, measured by a wavelength dispersive X-ray detector (WDX) mounted to an electron probe micro-analyzer (EPMA), is not greater than 0.2 mass %. 2. The glass sheet according to claim 1, wherein said difference of the visible light reflectance is not greater than 0.15%. 3. The glass sheet according to claim 1, wherein both the visible light reflectance of a surface formed in contact with the molten tin and the visible light reflectance of a surface on the opposite side thereof is not greater than 4.5%. 4. The glass sheet according to claim 3, wherein both the visible light reflectance of a surface formed in contact with the molten tin and the visible light reflectance of a surface on the opposite side thereof is not greater than 4.25%. 5. The glass sheet according to claim 1, wherein, in a rest without a portion up to a depth of 10 pm from the surface formed in contact with the molten tin, the glass sheet has a composition with an amount of iron oxide total in terms of Fe2O3 that is not greater than 0.04 mass %. 6. The glass sheet according to claim 5, wherein the composition is substantially free from cerium oxide. 7. The glass sheet according to claim 5, wherein the composition includes, in mass %: 65 to 80% SiO2, 0 to 5% Al2O3, 0 to 10% MgO, 5 to 15% CaO, 10 to 18% Na2O, 0 to 5% K2O, 5 to 15% MgO+CaO, 10 to 20% Na2O+K2O, 0.05 to 0.3% SO3, and 0 to 5% B2O3. 8. A glass sheet for a photoelectric conversion device comprising the glass sheet according to claim 1 and a conductive film deposited on that glass sheet. 9. The glass sheet for a photoelectric conversion device according to claim 8, wherein the conductive film is deposited on the surface opposite from the surface formed in contact with the molten tin. 10. The glass sheet for a photoelectric conversion device according to claim 8, further comprising an undercoating film disposed between the glass sheet and the conductive film. 11. The glass sheet according to claim 1, wherein the glass sheet is formed on the molten tin in a float bath in an atmosphere such that formation of the tin oxide in the molten tin is suppressed by maintaining a ratio of hydrogen gas to nitrogen gas in the atmosphere of the float bath at a level in which no tin oxide is found in the molten tin. 12. The glass sheet according to claim 1, wherein the iron concentration in the molten tin is less than 100 ppm. 13. The glass sheet according to claim 12, wherein the iron concentration in the molten tin is less than 95 ppm. 14. The glass sheet according to claim 12, wherein the iron concentration in the molten tin is less than 90 ppm.