VOTE

Abstract

The purpose of the present invention is to provide a glass that enables the containment of warping in solar cells while minimizing the deterioration of mechanical and optical properties, even when the glass is made thinner and larger. This glass has a relative density of 2.2 to 2.7, a Young's modulus of 60 GPa or more, and an average coefficient of thermal expansion at 50 to 200 °C of 2.0 to 6.0 (× 10⁻⁶). -6 / K) and is a rectangle where one side of the main surface is 50 cm to 300 cm and furthermore has a plate thickness of 0.01 mm to 0.5 mm and which, in mass percent on an oxide basis, contains a total content of Li2O, Na2O and K2O of 0 to 3.5% and 0.1 to 10% CeO2.

Description

TECHNICAL AREA

[0001] The present invention relates to a glass, and in particular a glass suitable as a solar cell cover glass for use in a space satellite, as a UV-blocking glass, as an electron beam shielding glass, or the like. STATE OF THE ART

[0002] A satellite constellation is a method of implementing a function or service by linking multiple satellites, ranging from several hundred to several thousand. Since building a satellite constellation requires a large number of satellites, reducing satellite costs is essential. Solar power generation using solar cells has been investigated as a power source for the satellites. Silicon is generally used for solar cells, and a protective cover glass is used to shield the cells.

[0003] For example, patent document 1 discloses a borosilicate glass composition suitable for use as a protective cover for solar cells in artificial satellites, such as a cover glass for space solar cells. Furthermore, patent document 2 discloses a glass substrate for space solar power generation. DOCUMENT LISTPATENT DOCUMENTS Patent Document 1: JP S63-95138 A Patent document 2: WO 2023 / 022074 SUMMARY OF THE INVENTIONAL PROBLEM

[0004] Especially when glass is used in space-based solar cells, low satellite costs are essential. To reduce costs, lowering the glass size and thickness can be achieved. However, due to the difference in thermal expansion coefficients between the silicon used in the solar cell and the glass, increased size and reduced thickness are expected to result in greater distortion of the solar cell compared to a prior art product. Furthermore, the thinner glass may compromise the mechanical and optical properties of the glass compared to the prior art product.

[0005] Therefore, it is an object of the present invention to provide a glass that can prevent a deterioration of mechanical and optical properties, while preventing distortion of a solar cell even in the case where the size is increased and the thickness is reduced. SOLUTION TO THE PROBLEM

[0006] The inventors of the present invention found that the aforementioned problems could be solved by adjusting the composition of a glass to a specific range and have thus made the present invention. That is to say, the present invention is as follows. 1. Glass with a relative density of 2.2 to 2.7, exhibits a Young's modulus of 60 GPa or more, an average coefficient of thermal expansion in a range of 50 °C to 200 °C of 2.0 to 6.0 (× 10 -6 / K) exhibits has a rectangular shape, a main surface with one side measuring 50 cm or more and 300 cm or less, has a thickness of 0.01 mm or more and 0.5 mm or less, exhibits a total content of Li2O, Na2O and K2O of 0% to 3.5% as mass % based on oxides, and Contains 0.1% to 10% CeO2 as mass-% based on oxides. 2. Glass according to the preceding 1, further comprising, as mass % based on oxides: 0.01 % to 10 % TiO2. 3. Glass according to the preceding 1, further containing, as mass % based on oxides: 5% to 10% TiO2. 4. Glass having a relative density of 2.2 to 2.7, exhibits a Young's modulus of 60 GPa or more, an average coefficient of thermal expansion in a range of 50 °C to 200 °C of 2.0 to 6.0 (× 10 -6 / K) exhibits has a rectangular shape, a main surface with one side measuring 50 cm or more and 300 cm or less, has a thickness of 0.01 mm or more and 0.5 mm or less, and Contains 5% to 10% TiO2 as mass-% based on oxides. 5. Glass, containing as mass % based on oxides: 50% to 80% SiO2; 0% to 25% B2O3; 0% to 30% Al2O3; and 0.1% to 10% CeO2, and that has a total content of Li2O, Na2O and K2O of 0% to 3.5%, has a rectangular shape, a main surface with one side measuring 50 cm or more and 300 cm or less, and has a thickness of 0.01 mm or more and 0.5 mm or less. 6. Glass, containing as mass % based on oxides: 50% to 80% SiO2; 0% to 25% B2O3; 0% to 30% Al2O3; and 5% to 10% TiO2, and that has a total content of Li2O, Na2O and K2O of 0% to 3.5%, has a rectangular shape, a main surface with one side measuring 50 cm or more and 300 cm or less, and has a thickness of 0.01 mm or more and 0.5 mm or less. 7. Glass, containing as mass % based on oxides: 50% to 80% SiO2; 0% to 25% B2O3; 0% to 30% Al2O3 0.01% to 10% TiO2; and 0.1% to 10% CeO2, and that has a total content of Li2O, Na2O and K2O of 0% to 3.5%, has a rectangular shape, a main surface with one side measuring 50 cm or more and 300 cm or less, and has a thickness of 0.01 mm or more and 0.5 mm or less. 8. Glass according to any of the preceding 5 to 7, having an average coefficient of thermal expansion in a range of 50 °C to 200 °C of 2.0 to 6.0 (× 10 -6 / K). 9. Glass according to any of the preceding 1 to 7, having a total content of As2O3 and Sb2O3 of 0% or more and less than 0.25% as mass % on the basis of oxides. 10. Glass according to any of the preceding 1 to 7, further containing, as mass % based on oxides: 0.01 % to 0.4 % or less SnO2. 11. Glass according to any of the preceding 1 to 7, having a BaO content of 0% or more and 6.5% or less as mass % based on oxides. 12. Glass according to any of the preceding 1 to 7, which exhibits an average extinction change magnitude in a wavelength range of 400 nm to 800 nm during electron beam irradiation of 0.01 or less based on a thickness of 100 µm. 13. Glass according to any of the preceding 1 to 7, which has a fracture toughness value (K IC ) of 0.78 MPa · m 1 / 2 or more. 14. Glass according to any of the preceding 1 to 7, which has a value of 50% or more obtained by subtracting a light transmittance at a wavelength of 300 nm from a light transmittance at a wavelength of 400 nm. 15. Glass according to any of the preceding 1 to 7, which has a value E / p, obtained by dividing a Young's modulus E (GPa) by a relative density p, of 27.0 GPa or more. 16. Glass according to any of the preceding 1 to 7, which has a β-OH of 1.0 mm -1 or less. 17. Glass according to any of the preceding 1 to 7, comprising: a conductive film on at least one surface. 18. Glass according to any of the preceding 1 to 7, comprising: an anti-reflective film on at least one surface. 19. Solar cell cover glass for a space satellite, comprising: the glass according to any of the preceding 1 to 7. 20. UV-blocking glass, comprising: the glass according to any of the preceding 1 to 7. 21. Electron beam shielding glass, comprising: the glass according to any of the preceding 1 to 7. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0007] Since the glasses according to the first and fifth embodiments of the present invention have a side of the main surface and the thickness within the specific ranges, the relative density, the Young's modulus and the coefficient of thermal expansion within the specific ranges and the glass composition within the specific range, distortion of a solar cell can be prevented and deterioration of mechanical and optical properties can be prevented.

[0008] Since the glasses according to the second to fourth embodiments of the present invention have a side of the main surface and the thickness within the specific areas and the glass composition within the specific area, the distortion of a solar cell can be prevented and the deterioration of mechanical and optical properties can be prevented. BRIEF DESCRIPTION OF THE DRAWINGS [ Fig. 1] Fig. Figure 1 is a diagram showing a correlation between an average coefficient of thermal expansion and (absolute value of the distortion δ / length in the distortion direction of the glass). DESCRIPTION OF EXECUTION FORMS

[0009] The present invention is described in detail below based on embodiments; however, the present invention is not limited to the following embodiments and can be freely modified and implemented without departing from the essential nature of the present invention. Furthermore, embodiments of the present invention (hereinafter also referred to as the present embodiment) include a first through fifth embodiment, which are described below. In this description, "to" indicating a numerical range is used in the sense that it encompasses the numerical values ​​indicated before and after the "to" as a lower limit and an upper limit, and unless otherwise specified, "to" is used below with the same meaning.

[0010] In this description, "is substantially free from" a particular component means that the component is not present, except for unavoidable impurities introduced from starting materials and the like. That is to say, it means that it is not intentionally included. It should be noted that, unless otherwise stated, in this description the content of each component of the glass is given as a mass percent based on oxides. <glas>

[0011] A glass according to the first embodiment has a relative density of 2.2 to 2.7, a Young's modulus of 60 GPa or more, and an average coefficient of thermal expansion in a range of 50 °C to 200 °C of 2.0 to 6.0 (× 10 -6 / K), a rectangular shape, a main surface with a side of 50 cm or more and 300 cm or less, a thickness of 0.01 mm or more and 0.5 mm or less and a total content of Li2O, Na2O and K2O of 0% to 3.5% as mass-% based on oxides and contains 0.1% to 10% CeO2 as mass-% based on oxides.

[0012] A glass according to the second embodiment contains, as mass percent based on oxides: 50% to 80% SiO2; 0% to 25% B2O3; 0% to 30% Al2O3; and 0.1% to 10% CeO2 and has a total content of Li2O, Na2O and K2O of 0% to 3.5%, a rectangular shape, a main surface area with one side of 50 cm² or more and 300 cm² or less and a thickness of 0.01 mm or more and 0.5 mm or less.

[0013] A glass according to the third embodiment contains, as mass percent based on oxides: 50% to 80% SiO2; 0% to 25% B2O3; 0% to 30% Al2O3; and 5% to 10% TiO2 and has a total content of Li2O, Na2O and K2O of 0% to 3.5%, a rectangular shape, a main surface area with one side of 50 cm² or more and 300 cm² or less and a thickness of 0.01 mm or more and 0.5 mm or less.

[0014] A glass according to the fourth embodiment contains, as mass percent based on oxides: 50% to 80% SiO2; 0% to 25% B2O3; 0% to 30% Al2O3; 0.01% to 10% TiO2; and 0.1% to 10% CeO2 and has a total content of Li2O, Na2O and K2O of 0% to 3.5%, a rectangular shape, a main surface area with one side of 50 cm² or more and 300 cm² or less and a thickness of 0.01 mm or more and 0.5 mm or less.

[0015] A glass according to the fifth embodiment has a relative density of 2.2 to 2.7, a Young's modulus of 60 GPa or more, and an average coefficient of thermal expansion in a range of 50 °C to 200 °C of 2.0 to 6.0 (× 10 -6 / K), a rectangular shape, a main surface with a side of 50 cm or more and 300 cm or less and a thickness of 0.01 mm or more and 0.5 mm or less, and contains 5% to 10% TiO2 as mass-% based on oxides.

[0016] The glasses according to the first and fifth embodiments have a relative density of 2.2 to 2.7. The glasses according to the first and fifth embodiments preferably have a relative density of 2.21 or more, 2.22 or more, 2.23 or more, 2.24 or more, 2.25 or more, 2.26 or more, 2.27 or more, 2.28 or more, 2.29 or more, 2.30 or more, 2.31 or more, 2.32 or more, 2.33 or more, 2.34 or more, 2.35 or more, 2.36 or more, 2.37 or more, or 2.38 or more.The glasses according to the first and fifth embodiments preferably have a relative density of 2.69 or less, 2.68 or less, 2.67 or less, 2.66 or less, 2.65 or less, 2.64 or less, 2.63 or less, 2.62 or less, 2.61 or less, 2.60 or less, 2.59 or less, 2.58 or less, 2.57 or less, 2.56 or less, 2.55 or less, 2.54 or less, 2.53 or less, 2.52 or less, 2.51 or less, 2.50 or less, 2.49 or less, 2.48 or less, 2.47 or less, or 2.46 or less.

[0017] The glasses according to the second to fourth embodiments preferably have a relative density of 2.2 to 2.7. The glasses according to the second to fourth embodiments more preferably have a relative density of 2.21 or more, 2.22 or more, 2.23 or more, 2.24 or more, 2.25 or more, 2.26 or more, 2.27 or more, 2.28 or more, 2.29 or more, 2.30 or more, 2.31 or more, 2.32 or more, 2.33 or more, 2.34 or more, 2.35 or more, 2.36 or more, 2.37 or more, or 2.38 or more.The glasses according to the second to fourth embodiments more preferably have a relative density of 2.69 or less, 2.68 or less, 2.67 or less, 2.66 or less, 2.65 or less, 2.64 or less, 2.63 or less, 2.62 or less, 2.61 or less, 2.60 or less, 2.59 or less, 2.58 or less, 2.57 or less, 2.56 or less, 2.55 or less, 2.54 or less, 2.53 or less, 2.52 or less, 2.51 or less, 2.50 or less, 2.49 or less, 2.48 or less, 2.47 or less or 2.46 or less.

[0018] If the relative density is 2.2 or higher, electron and proton beams are effectively shielded, and deterioration of a solar cell can be prevented, particularly when the glass is used as a solar cell cover. If the relative density is 2.7 or lower, a reduction in weight can be achieved even with increased size.

[0019] The relative density is measured using the Archimedes method.

[0020] The glasses according to the first and fifth embodiments have a Young's modulus of 60 GPa or more, and preferably 61 GPa or more, 62 GPa or more, 63 GPa or more, 64 GPa or more, 65 GPa or more, 66 GPa or more, 67 GPa or more, 68 GPa or more, 69 GPa or more, 70 GPa or more, 71 GPa or more, or 72 GPa or more.

[0021] The glasses according to the second to fourth embodiments preferably have a Young's modulus of 60 GPa or more and more preferably 61 GPa or more, 62 GPa or more, 63 GPa or more, 64 GPa or more, 65 GPa or more, 66 GPa or more, 67 GPa or more, 68 GPa or more, 69 GPa or more, 70 GPa or more, 71 GPa or more or 72 GPa or more.

[0022] If the Young's modulus is 60 GPa or more, the fracture toughness is increased, thus improving the strength and ensuring the strength required for increasing the size and decreasing the thickness.

[0023] On the other hand, with regard to reducing the generation of thermal stress due to a rapid temperature difference, the Young's modulus of the glass according to the present embodiment is preferably 105 GPa or less, more preferably 100 GPa or less, even more preferably 95 GPa or less and particularly preferably 90 GPa or less.

[0024] The Young's modulus is measured using the ultrasonic pulse method (JIS R1602, 1995).

[0025] In the glass according to the present embodiment, the E / p value obtained by dividing the Young's modulus E (GPa) by the relative density p is preferably 27.0 GPa to 37.0 GPa. More preferably, the E / p value is 27.2 GPa or more, 27.4 GPa or more, 27.6 GPa or more, 27.8 GPa or more, 28.0 GPa or more, 28.2 GPa or more, 28.4 GPa or more, 28.6 GPa or more, 28.8 GPa or more, or 29.0 GPa or more. Furthermore, the E / p value is preferably 36.8 GPa or less, 36.6 GPa or less, 36.4 GPa or less, 36.2 GPa or less, 36.0 GPa or less, 35.8 GPa or less, 35.6 GPa or less, 35.4 GPa or less, 35.2 GPa or less, or 35.0 GPa or less. If the E / p value is 27.0 GPa or more, the strength required for increasing the size and decreasing the thickness can be ensured.If the E / p value is 37.0 GPa or less, the strength required for increasing the size and decreasing the thickness can be improved, while a reduction in weight is ensured when the size is increased.

[0026] Increasing the size and decreasing the thickness of the glass used in a solar cell makes warping of the solar cell due to a difference in the coefficient of thermal expansion between silicon and the glass that forms the solar cell a problem. As described in the Fig. As shown in Figure 1, an absolute value of a distortion magnitude δ has a correlation with the average coefficient of thermal expansion, and it is assumed that the distortion of the solar cell, when used in the solar cell, can be effectively reduced by setting the range of the average coefficient of thermal expansion.

[0027] The glasses according to the first and fifth embodiments have an average coefficient of thermal expansion in a range of 50 °C to 200 °C of 2.0 to 6.0 (× 10 -6 / K). In the glasses according to the first and fifth embodiments, the average coefficient of thermal expansion in a range from 50 °C to 200 °C is preferably 2.1 (× 10 -6 / K) or more, 2.2 (× 10 -6 / K) or more, 2.3 (× 10 -6 / K) or more, 2.4 (× 10 -6 / K) or more, 2.5 (× 10 -6 / K) or more, 2.6 (× 10 -6 / K) or more, 2.7 (× 10- 6 / K) or more, 2.8 (× 10 -6 / K) or more, 2.9 (× 10 -6 / K) or more, 3.0 (× 10 -6 / K) or more, 3.1 (× 10 -6 / K) or more or 3.2 (× 10 -6 / K) or more. In the glasses according to the first and fifth embodiments, the average coefficient of thermal expansion in a range from 50 °C to 200 °C is preferably 5.9 (× 10 -6 / K) or less, 5.8 (× 10 -6 / K) or less, 5.7 (× 10 -6 / K) or less, 5.6 (× 10 -6 / K) or less, 5.5 (× 10 -6 / K) or less, 5.4 (× 10 -6 / K) or less, 5.3 (× 10 -6 / K) or less, 5.2 (× 10 -6 / K) or less, 5.1 (× 10 -6 / K) or less, 5.0 (× 10 -6 / K) or less, 4.9 (× 10 -6 / K) or less, 4.8 (× 10 -6 / K) or less, 4.7 (× 10 -6 / K) or less, 4.6 (× 10 -6 / K) or less or 4.5 (× 10- 6 / K) or less.

[0028] The glasses according to the second to fourth embodiments preferably have an average coefficient of thermal expansion in a range of 50 °C to 200 °C of 2.0 to 6.0 (× 10 -6 / K). In the glasses according to the second to fourth embodiments, the average coefficient of thermal expansion in a range of 50 °C to 200 °C is more preferably 2.1 (× 10 -6 / K) or more, 2.2 (× 10 -6 / K) or more, 2.3 (× 10 -6 / K) or more, 2.4 (× 10 -6 / K) or more, 2.5 (× 10 -6 / K) or more, 2.6 (× 10- 6 / K) or more, 2.7 (x 10 -6 / K) or more, 2.8 (× 10 -6 / K) or more, 2.9 (× 10 -6 / K) or more, 3.0 (× 10 -6 / K) or more, 3.1 (× 10 -6 / K) or more or 3.2 (× 10 -6 / K) or more. In the glasses according to the second to fourth embodiments, the average coefficient of thermal expansion in a range of 50 °C to 200 °C is preferably 5.9 (× 10 -6 / K) or less, 5.8 (× 10 -6 / K) or less, 5.7 (× 10 -6 / K) or less, 5.6 (× 10 -6 / K) or less, 5.5 (× 10 -6 / K) or less, 5.4 (× 10 -6 / K) or less, 5.3 (× 10 -6 / K) or less, 5.2 (× 10 -6 / K) or less, 5.1 (× 10 -6 / K) or less, 5.0 (× 10 -6 / K) or less, 4.9 (× 10 -6 / K) or less, 4.8 (× 10 -6 / K) or less, 4.7 (× 10 -6 / K) or less, 4.6 (× 10 -6 / K) or less or 4.5 (× 10 -6 / K) or less.

[0029] If the average coefficient of thermal expansion is within the range of 50 °C to 200 °C, the distortion of the solar cell due to a difference in the coefficient of thermal expansion between silicon and the glass used in the solar cell, particularly in the case of the use of a solar cell cover glass, can be reduced.

[0030] In this description, the average coefficient of thermal expansion is measured using a differential thermal expansion gauge according to a procedure specified in JIS R3102 (1995). The measurement temperature range is 50 °C to 200 °C and the unit is × 10⁻⁶. -6 / K.

[0031] The glass according to the present embodiment has a rectangular shape and a main surface with one side measuring 50 cm or more and 300 cm or less. If one side of the main surface is 50 cm or more, the labor required to assemble the solar cell is reduced, and a reduction in cost can be achieved by increasing the size. Furthermore, if one side of the main surface is 300 cm or less, thin glass without cracks can be easily handled, and cost reduction can be achieved. The length of one side of the main surface is preferably 60 cm or more, 70 cm or more, and 80 cm or more in that order; more preferably 90 cm or more, 100 cm or more, and 110 cm or more in that order; still more preferably 120 cm or more, 130 cm or more, and 140 cm or more in that order; and particularly preferably 150 cm or more.Furthermore, the length of one side of the main surface is more preferably 290 cm or less, 280 cm or less, 270 cm or less, 260 cm or less, 250 cm or less, 240 cm or less, 230 cm or less, 220 cm or less, 210 cm or less, or 200 cm or less.

[0032] The glass according to the present embodiment has a thickness of 0.01 mm or more and 0.5 mm or less. If the thickness is 0.01 mm or more, sufficient strength can be ensured and the electron and proton beams can be adequately shielded. Furthermore, if the thickness is 0.5 mm or less, a reduction in weight can be achieved, particularly in space applications. The thickness is preferably 0.48 mm or less, 0.46 mm or less, 0.44 mm or less, 0.42 mm or less, 0.40 mm or less, 0.38 mm or less, 0.36 mm or less, 0.34 mm or less, 0.32 mm or less, 0.30 mm or less, 0.28 mm or less, 0.26 mm or less, 0.24 mm or less, 0.22 mm or less, 0.20 mm or less, 0.18 mm or less, 0.16 mm or less, 0.14 mm or less, 0.12 mm or less, or 0.10 mm or less.Furthermore, the thickness is preferably 0.02 mm or more, 0.03 mm or more, 0.04 mm or more, or 0.05 mm or more.

[0033] In the glass according to the present embodiment, the average extinction change in a wavelength range of 400 nm to 800 nm, based on a thickness of 100 µm, during electron beam irradiation is preferably 0.01 or less, and more preferably 0.009 or less, 0.008 or less, 0.007 or less, 0.006 or less, or 0.005 or less. If the average extinction change, based on a thickness of 100 µm, is 0.01 or less, staining due to the electron beam is prevented, and sufficient optical properties for space applications can be ensured. The lower limit of the average extinction change, based on a thickness of 100 µm, is not particularly restricted and is, for example, 0.0001 or more.

[0034] In the present description, the value “based on a thickness of 100 µm” refers to a value obtained by converting the extinction change magnitude into a value when the thickness of the glass is 100 µm.

[0035] The average extinction change magnitude in the wavelength range from 400 nm to 800 nm, based on a thickness of 100 µm during electron beam irradiation, is determined by the following method. (a1) For electron beam irradiation, a glass substrate to be irradiated is placed horizontally on a table and the glass substrate is irradiated with an electron beam of 1 × 10 15 electrons / cm 2 irradiated at an energy level of 1 MeV using an electron beam irradiation device (e.g., model number EPS-3000 kV, manufactured by NHV Corporation). (a2) The transmittance is measured for each glass substrate after electron beam irradiation. The measurement is carried out within one week after electron beam irradiation. The absorbance before and after electron beam irradiation is calculated based on the measured transmittance and converted into the absorbance at a thickness of 100 µm. (a3) The average extinction change magnitude in the wavelength range from 400 nm to 800 nm is calculated according to the following equation. ∑λ=400800(Anach[λ]−Avor[λ])400 A [λ]: Extinction at wavelength λ A nach [λ]: Extinction at wavelength λ before electron beam irradiation A vor [λ]: Extinction at wavelength λ after electron beam irradiation

[0036] In the glass according to the present embodiment, a value obtained by subtracting the light transmittance at a wavelength of 300 nm from the light transmittance at a wavelength of 400 nm at a thickness of 100 µm is preferably 50% or more, and more preferably 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, or 80% or more. If the value is 50% or more, deterioration of the solar cell's properties due to the electron beam can be effectively prevented, particularly in space applications. The upper limit of the value is not specifically restricted and is, for example, 95% or less.

[0037] The transmittance can be measured using a spectrophotometer (for example, the U-4100, manufactured by Hitachi High-Tech Corporation).

[0038] The glass according to the present embodiment preferably has a transmittance of 80% to 93% at a wavelength of 400 nm and a thickness of 100 µm. The transmittance is more preferably 81% or more, more preferably 82% or more, more preferably 83% or more, more preferably 84% or more, more preferably 85% or more, and most preferably 86% or more. If the transmittance at a wavelength of 400 nm and a thickness of 100 µm is 80% or more, the power generation characteristics of the solar cell can be further improved when the glass is used as a solar cell cover glass.

[0039] In the present description, the permeability at a thickness of 100 µm refers to the permeability measured at a thickness of 100 µm.

[0040] The glass according to the present embodiment preferably has a transmittance of 0% to 10% at a wavelength of 300 nm and a thickness of 100 µm. The transmittance is more preferably 0.5% or more, more preferably 1% or more, more preferably 1.5% or more, more preferably 2% or more, more preferably 2.5% or more, and most preferably 3% or more. If the transmittance at a wavelength of 300 nm and a thickness of 100 µm is 0% or more, the power generation characteristics of the solar cell can be further improved when the glass is used as a cover glass for the solar cell. If the transmittance at a wavelength of 300 nm and a thickness of 100 µm is 10% or less, degradation of the solar cell due to ultraviolet radiation can be prevented.

[0041] In the glass according to the present embodiment, a wavelength at which a transmittance of 50% is achieved at a thickness of 100 µm is preferably 300 nm to 370 nm. The wavelength is more preferably 310 nm or more, even more preferably 320 nm or more, and particularly preferably 330 nm or more. Furthermore, the wavelength is more preferably 360 nm or less, even more preferably 355 nm or less, and even more preferably 350 nm or less. If the wavelength is 300 nm or more, deterioration of the solar cell due to ultraviolet radiation can be prevented. If the wavelength is 370 nm or less, the power generation characteristics of the solar cell can be further improved if the glass is used as a solar cell cover glass.

[0042] The glass according to the present embodiment preferably has a transmittance of 80% to 94% at a wavelength of 400 nm and a thickness of 50 µm. The transmittance is more preferably 81% or more, more preferably 82% or more, more preferably 83% or more, more preferably 84% or more, more preferably 85% or more, and particularly preferably 86% or more. Furthermore, the transmittance is preferably 94% or less, more preferably 93% or less, more preferably 92% or less, more preferably 91% or less, and particularly preferably 90% or less. If the transmittance at a wavelength of 400 nm and a thickness of 50 µm is 80% or more, the power generation characteristics of the solar cell can be further improved if the glass is used as a solar cell cover glass.

[0043] In the present description, the permeability at a thickness of 50 µm refers to the permeability measured at a thickness of 50 µm.

[0044] The glass according to the present embodiment preferably has a transmittance of 0% to 25% at a wavelength of 300 nm and a thickness of 50 µm. The transmittance is more preferably 1% or more, more preferably 2% or more, more preferably 3% or more, more preferably 4% or more, more preferably 5% or more, and particularly preferably 7% or more. Furthermore, the transmittance is more preferably 23% or less, more preferably 20% or less, more preferably 15% or less, and particularly preferably 10% or less. If the transmittance at a wavelength of 300 nm is 0% or more at 50 µm, the power generation characteristics of the solar cell can be further improved if the glass is used as a solar cell cover glass.If the transmittance at a wavelength of 300 nm at 50 µm is 25% or less, deterioration of the solar cell due to ultraviolet radiation can be prevented.

[0045] In the glass according to the present embodiment, a wavelength at which a transmittance of 50% is achieved at a thickness of 50 µm is preferably 250 nm to 360 nm. The wavelength is more preferably 260 nm or more, even more preferably 270 nm or more, particularly preferably 280 nm or more, even more preferably 290 nm or more, and even more preferably 300 nm or more. Furthermore, the wavelength is more preferably 350 nm or less, even more preferably 340 nm or less, even more preferably 330 nm or less, particularly preferably 320 nm or less, and especially 310 nm or less. If the wavelength is 250 nm or more, deterioration of the solar cell due to ultraviolet radiation can be prevented. If the wavelength is 360 nm or less, sufficient optical properties can be ensured even in the case of increased size.

[0046] In the glass according to the present embodiment, the fracture toughness value K is IC preferably 0.78 MPa · m 1 / 2 or more, preferably 0.80 MPa · m 1 / 2 or more, preferably 0.81 MPa · m 1 / 2 or more, and especially preferably 0.82 MPa · m 1 / 2 or more. If K IC 0.78 MPa · m 1 / 2 or more, sufficient strength can be ensured even in cases where the size is increased. The upper limit of the fracture toughness value K IC is not specifically limited and can, for example, be 1.00 MPa · m 1 / 2 or less.

[0047] In the present description, the fracture toughness value K refers to IC to a value measured using a double cleavage drilled compression (DCDC) method (Acta metall. mater., Vol. 43, pp. 3453-3458, 1995) or an SSEP method specified in JIS R1607 (2015). Since the DCDC method determines the fracture toughness value K IC The fracture toughness value K can be determined more accurately than the SEPB method. IC A value that can be determined using the DCDC method is preferred.

[0048] In the glass according to the present embodiment, β-OH is preferably 1.0 mm. -1 or less, preferably more 0.5 mm -1 or less, preferably 0.4 mm -1 or less and especially preferably 0.3 mm -1 or less. If β-OH 1.0 mm -1 If the β-OH value is less than or equal to 0.01 mm, the amount of platinum eluted into the glass from a platinum crucible, platinum stirrer, or other production equipment or plant components where platinum is used can be increased, and the ultraviolet radiation absorption effect can be improved. The lower limit of β-OH is not specifically restricted and is, for example, 0.01 mm. -1 or more.

[0049] The β-OH of the glass is determined by measuring the transmittance of the glass using FT-IR and by using the following equations. β−OH=(1X)log10(T1T2) X: Thickness (mm) of the glass T1: Transmittance (%) at a reference wavelength of 3846 cm -1 T2: Minimum transmittance (%) in the vicinity of the hydroxyl group absorption wavelength of 3600 cm⁻¹ -1

[0050] In the glass according to the present embodiment, the “absolute value of the distortion δ / length in the distortion direction of the glass” is a value obtained by dividing the absolute value of the calculated distortion δ by the length (mm) in a distortion direction of the glass on the basis of a bimetallic distortion calculation defined by the following equation, preferably e.g. the following (b1) to (b4). (b1) In the case where the length in the distortion direction of the glass is 1000 mm and the thickness of the glass is 0.1 mm, the absolute value of the distortion δ / length in the distortion direction of the glass is preferably 0.30 or less, more preferably 0.20 or less, even more preferably 0.15 or less, particularly preferably 0.10 or less, and especially 0.05 or less. The absolute value of the distortion δ / length in the distortion direction of the glass is preferably as small as possible, and its lower limit is not specifically limited and is, for example, 0.001 or more. (b2) In the case where the length in the distortion direction of the glass is 1000 mm and the thickness of the glass is 0.05 mm, the absolute value of the distortion δ / length in the distortion direction of the glass is preferably 0.20 or less, more preferably 0.15 or less, even more preferably 0.10 or less, and particularly preferably 0.05 or less. The absolute value of the distortion δ / length in the distortion direction of the glass is preferably as small as possible, its lower limit not being specifically restricted and being, for example, 0.001 or more. (b3) In the case where the length in the distortion direction of the glass is 500 mm and the thickness of the glass is 0.1 mm, the absolute value of the distortion δ / length in the distortion direction of the glass is preferably 0.20 or less, more preferably 0.15 or less, even more preferably 0.10 or less, and particularly preferably 0.05 or less. The absolute value of the distortion δ / length in the distortion direction of the glass is preferably as small as possible, and its lower limit is not specifically restricted and is, for example, 0.001 or more. (b4) In the case where the length in the distortion direction of the glass is 500 mm and the thickness of the glass is 0.05 mm, the absolute value of the distortion δ / length in the distortion direction of the glass is preferably 0.20 or less, more preferably 0.15 or less, even more preferably 0.10 or less, and particularly preferably 0.05 or less. The absolute value of the distortion δ / length in the distortion direction of the glass is preferably as small as possible, and its lower limit is not specifically restricted and is, for example, 0.001 or more.

[0051] If (absolute value of the distortion extent δ / length in the distortion direction of the glass) is identical to or smaller than the upper limit for (b1) to (b4), the function of the solar cell can be ensured even in the case where the solar cell glass has a reduced thickness and an increased size. δ=6L2(α1−α1)(T2−T1)(1+m)28h[3(1+m)2+(1+nm){m2+(mm)−1}] L: Length [mm] in the direction of distortion of the glass α1: Coefficient of thermal expansion [ppm / K] of the solar cell α2: Coefficient of thermal expansion [ppm / K] of the glass E1: Young's modulus [GPa] of the solar cell E2: Young's modulus [GPa] of the glass T1: Assumed maximum temperature (°C) T2: Assumed minimum temperature (°C) a1: Thickness [mm] of the solar cell a2: Thickness [mm] of the glass h: a1 + a2 [mm] m: a1 / a2 n: E1 / E2 δ: Deformation dimension [mm]

[0052] It is assumed that the solar cell used is "MAXEON™ GENIII SOLAR CELLS" manufactured by Sunpower, as a single-crystal silicon. The coefficient of thermal expansion and the Young's modulus of the solar cell are α1 = 3.2 ppm / °C and E1 = 190 GPa, respectively, again assuming the use of single-crystal silicon. The coefficient of thermal expansion of the glass is a value of the average coefficient of thermal expansion (ppm / °C) in the range of 50 °C to 200 °C. The thickness of the solar cell is assumed to be 0.15 mm.

[0053] The glass according to the present embodiment has a temperature (T2) at which the logarithmic viscosity η2 (poise) is preferably 1800 °C or lower, more preferably 1750 °C or lower, and even more preferably 1700 °C or lower, with a view to reducing viscosity, improving productivity, and achieving SDGs. T2 is generally 1400 °C or higher.

[0054] The glass according to the present embodiment has a temperature (T4) at which the logarithmic viscosity η4 (poise) is preferably 1550 °C or lower, more preferably 1500 °C or lower, more preferably 1450 °C or lower, 1400 °C or lower, and 1350 °C or lower in that order, and particularly 1300 °C or lower, with a view to reducing viscosity, improving productivity, and achieving SDGs. T4 is generally 800 °C or higher.

[0055] The glass according to the present embodiment has an average flatness (Ra) within 1 µm × 1 µm of preferably 2.0 nm or less, more preferably 1.5 nm or less, more preferably 1.0 nm or less, and more preferably 0.8 nm or less, wherein the flatness (Ra) within 1 µm × 1 µm is obtained by cutting five 50 mm × 50 mm pieces of glass from a glass with a side of 50 cm or more at the center and at positions near four corners, and performing a measurement using AFM. A flatness of 2.0 nm or less provides strength that makes breakage during handling less likely.The lower limit of the average value of the flatness is preferably 0.2 nm or more, more preferably 0.3 nm or more, even more preferably 0.4 nm or more and even more preferably 0.5 nm or more, since a certain degree of roughness helps to reduce the static electricity from an intermediate paper placed between the glass and the glass during handling. < <zusammensetzung>>

[0056] In the first to fourth embodiments, R2O (the total content of Li2O, Na2O and K2O) is 0% to 3.5%. In the first to fourth embodiments, R2O is preferably 3.4% or less, 3.3% or less, 3.2% or less, 3.1% or less, 3.0% or less, 2.9% or less, 2.8% or less, 2.7% or less, 2.6% or less, 2.5% or less, 2.4% or less, 2.3% or less, 2.2% or less, 2.1% or less, 2.0% or less, 1.9% or less, 1.8% or less, 1.7% or less, 1.6% or less, 1.5% or less, 1.4% or less, 1.3% or less, 1.2% or less, 1.1% or less, 1.0% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less. 0.5% or less, 0.4% or less, 0.3% or less, 0.2% or less, or 0.1% or less.

[0057] In the fifth embodiment, R2O is preferably 0% to 3.5%. In the fifth embodiment, R2O is more preferably 3.4% or less, 3.3% or less, 3.2% or less, 3.1% or less, 3.0% or less, 2.9% or less, 2.8% or less, 2.7% or less, 2.6% or less, 2.5% or less, 2.4% or less, 2.3% or less, 2.2% or less, 2.1% or less, 2.0% or less, 1.9% or less, 1.8% or less, 1.7% or less, 1.6% or less, 1.5% or less, 1.4% or less, 1.3% or less, 1.2% or less, 1.1% or less, 1.0% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, 0.5 % or less, 0.4% or less, 0.3% or less, 0.2% or less, or 0.1% or less.

[0058] By adjusting R2O to 3.5% or less, the difference in the coefficient of thermal expansion between silicon and the glass used in the solar cell can be reduced, and the distortion of the solar cell can be effectively reduced even when the size is increased. R2O is preferably as small as possible and, for manufacturability reasons, is, for example, 0.01% or less.

[0059] Li₂O is an optional component that improves the Young's modulus and fracture toughness of the glass and enhances its mechanical properties. In the present embodiment, when Li₂O is included, its content is preferably 0.01% or more, more preferably 0.02% or more, even more preferably 0.03% or more, particularly preferably 0.04% or more, and especially 0.1% or more. Furthermore, with a view to reducing the difference in the coefficient of thermal expansion between silicon and the glass and effectively reducing distortion of the solar cell itself in cases of increased size, the Li₂O content is preferably 2.0% or less, more preferably 1.5% or less, even more preferably 1.0% or less, and particularly preferably 0.5% or less.

[0060] Na₂O is an optional component that improves the meltability of the glass and may be included. In the present embodiment, if Na₂O is included, its content is preferably 0.01% or more, more preferably 0.02% or more, even more preferably 0.05% or more, particularly preferably 0.5% or more, and especially 1.0% or more. Furthermore, with a view to reducing the difference in the coefficient of thermal expansion between silicon and the glass and effectively reducing distortion of the solar cell itself in the case where the size is increased, the content of Na₂O is preferably 2.0% or less, more preferably 1.5% or less, even more preferably 1.2% or less, and particularly preferably 1.1% or less.

[0061] K₂O is an optional component that improves the meltability of the glass and may be included. In the present embodiment, if K₂O is included, its content is preferably 0.01% or more, more preferably 0.02% or more, even more preferably 0.03% or more, and particularly preferably 0.05% or more. Furthermore, with a view to reducing the difference in the coefficient of thermal expansion between silicon and the glass and effectively reducing distortion of the solar cell itself in the case where the size is increased, the content of K₂O is preferably 3.0% or less, more preferably 2.0% or less, even more preferably 1.5% or less, particularly preferably 1.0% or less, and especially 0.5% or less.

[0062] Due to exposure to ultraviolet rays, electron beams, proton beams, and cosmic radiation (e.g., gamma and alpha radiation), glass tends to deteriorate, and its transmittance properties tend to worsen. Therefore, examples of properties required for glass used as solar cell cover glass in space applications include transmittance of a spectrally sensitive wavelength range of the solar cell, shielding from ultraviolet rays, electron beams, proton beams, and cosmic radiation, and not deterioration of transmittance properties as a result of these radiations.

[0063] CeO2 is a component that improves the ultraviolet radiation shielding effect and prevents staining due to the electron beam.

[0064] In the first, second, and fourth embodiments, the CeO2 content is 0.1% to 10% to ensure sufficient coloration of the glass due to the electron beam and the ultraviolet radiation shielding effect. In the first, second, and fourth embodiments, the CeO2 content is more preferably 0.2% or more, 0.4% or more, and 0.6% or more in that order; more preferably 0.8% or more, 1.0% or more, and 1.2% or more in that order; and particularly preferably 1.4% or more, 1.6% or more, and 1.8% or more in that order. Furthermore, in the first, second, and fourth embodiments, the CeO2 content is preferably 10% or less to prevent devitrification; more preferably 7% or less; more preferably 6% or less; particularly preferably 5% or less; and especially 3% or less.

[0065] In the third and fifth embodiments, the CeO2 content is preferably 0.1% to 10% to ensure sufficient coloration of the glass due to the electron beam and ultraviolet radiation shielding effect. In the third and fifth embodiments, the CeO2 content is more preferably 0.2% or more, 0.4% or more, and 0.6% or more in that order, more preferably 0.8% or more, 1.0% or more, and 1.2% or more in that order, and particularly preferably 1.4% or more, 1.6% or more, and 1.8% or more in that order. Furthermore, in the third and fifth embodiments, the CeO2 content is preferably 10% or less to prevent devitrification, more preferably 7% or less, more preferably 6% or less, particularly preferably 5% or less, and especially 3% or less.

[0066] In the present embodiment, when the thickness t is (mm) and the CeO2 content in the glass composition is α (wt%), α / t is preferably 0.2 wt% / mm to 200 wt% / mm to improve the ultraviolet shielding effect. α / t is more preferably 5 wt% / mm or more, more preferably 10 wt% / mm or more, and particularly preferably 15 wt% / mm or more. Furthermore, in the present embodiment, α / t is more preferably 160 wt% / mm or less, more preferably 120 wt% / mm or less, and particularly preferably 80 wt% / mm or less.

[0067] TiO2 is a component that prevents solarization by UVC.

[0068] In the first and second embodiments, the TiO2 content is preferably 0.01% to 10%. In the first and second embodiments, to better prevent solarization by UVC, the TiO2 content is preferably 0.30% or more, 0.50% or more, and 0.70% or more in that order, more preferably 1.0% or more, 1.2% or more, and 1.4% or more in that order, and even more preferably 1.5% or more, 2.0% or more, 3.0% or more, 4.0% or more, and 5.0% or more in that order. Furthermore, in the first and second embodiments, to even better prevent solarization by UVC and to prevent discoloration of the glass, the TiO2 content is more preferably 7% or less, more preferably 6% or less, and particularly preferably 5% or less.

[0069] In the third and fifth embodiments, the TiO2 content is 5% to 10%. In the third and fifth embodiments, the TiO2 content is preferably 5.5% or more, more preferably 6.0% or more, and even more preferably 7% or more, to further improve the prevention of solarization by UVC. Furthermore, in the third and fifth embodiments, to further improve the prevention of solarization by UVC and to prevent discoloration of the glass, the TiO2 content is preferably 9.0% or less, more preferably 8.5% or less, even more preferably 8.0% or less, and particularly preferably 7.5% or less.

[0070] In the fourth embodiment, the TiO2 content is 0.01% to 10%. In the fourth embodiment, to further improve the prevention of solarization by UVC, the TiO2 content is preferably 0.30% or more, 0.50% or more, and 0.70% or more in that order, more preferably 1.0% or more, 1.2% or more, and 1.4% or more in that order, and even more preferably 1.5% or more, 2.0% or more, and 3.0% or more in that order. Furthermore, in the fourth embodiment, to further improve the prevention of solarization by UVC and to prevent discoloration of the glass, the TiO2 content is more preferably 7.0% or less, more preferably 6.0% or less, and particularly preferably 5.0% or less.

[0071] In the first, second, and fourth embodiments, if the thickness t is (mm) and the TiO2 content in the glass composition is β (wt%), β / t is preferably 0.005 wt% / mm to 200 wt% / mm with regard to preventing solarization by UVC. In the first, second, and fourth embodiments, β / t is more preferably 1 wt% / mm or more, more preferably 5 wt% / mm or more, and particularly preferably 10 wt% / mm or more. Furthermore, in the first, second, and fourth embodiments, β / t is more preferably 160 wt% / mm or less, more preferably 120 wt% / mm or less, and particularly preferably 80 wt% / mm or less.

[0072] In the third and fifth embodiments, if the thickness t is (mm) and the TiO2 content in the glass composition is β (wt%), β / t is preferably 10 wt% / mm to 200 wt% / mm to prevent solarization by UVC. In the third and fifth embodiments, β / t is more preferably 50 wt% / mm or more, more preferably 100 wt% / mm or more, and particularly preferably 150 wt% / mm or more. Furthermore, in the third and fifth embodiments, β / t is more preferably 190 wt% / mm or less, more preferably 180 wt% / mm or less, and particularly preferably 170 wt% / mm or less.

[0073] In the glass according to the present embodiment, the value of X, represented by the following equation, is preferably 0.5 or more and 50 or less, with a view to further improving the ultraviolet radiation shielding effect and adjusting the wavelength at which the transmittance in an ultraviolet range towards a longer wavelength is 50%. The value of X is more preferably 40 or less, more preferably 35 or less, and particularly preferably 30 or less. The value of X is more preferably 1 or more, more preferably 3 or more, and particularly preferably 5 or more. X=5×[CeO2]+[TiO2]

[0074] In the equation, the brackets [] represent the content as mass % based on oxides.

[0075] SiO2 is a component that forms a glass framework and is essential.

[0076] In the first and fifth embodiments, the SiO2 content is preferably 50% to 80%. In the first and fifth embodiments, the SiO2 content is more preferably 51% or more, more preferably 52% or more, particularly preferably 53% or more, and especially 55% or more. Furthermore, in the first and fifth embodiments, the SiO2 content is more preferably 75% or less, more preferably 70% or less, particularly preferably 65% ​​or less, and especially 60% or less. If the SiO2 content is 50% or more, the long-term chemical resistance can be improved. If the SiO2 content is 80% or less, an increase in T2 or T4 can be prevented, and the meltability or formability of the glass can be improved.

[0077] In the second to fourth embodiments, the SiO2 content is 50% to 80%. In the second to fourth embodiments, the SiO2 content is preferably 51% or more, more preferably 52% or more, even more preferably 53% or more, and particularly preferably 55% or more. Furthermore, in the second to fourth embodiments, the SiO2 content is preferably 75% or less, more preferably 70% or less, even more preferably 65% ​​or less, and particularly preferably 60% or less. If the SiO2 content is 50% or more, the long-term chemical resistance can be improved. If the SiO2 content is 80% or less, an increase in T2 or T4 can be prevented, and the meltability or formability of the glass can be improved.

[0078] B₂O₃ can be included to improve meltability at high temperatures or glass strength. On the other hand, if the B₂O₃ content is high, the Young's modulus decreases, fracture toughness decreases, and strength tends to decrease. Furthermore, the glass is likely to undergo phase separation and lose transparency, making it difficult to obtain a homogeneous glass, and the glass's formability may decrease. In the first and fifth embodiments, when B₂O₃ is included, its content is preferably 25% or less, more preferably 20% or less, more preferably 18% or less, particularly preferably 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, and 12% or less in that order, and particularly 10% or less. In the second to fourth embodiments, the B₂O₃ content is 0% to 25%.In the second to fourth embodiments, the B₂O₃ content is preferably 20% or less, more preferably 17% or less, even more preferably 15% or less, particularly preferably 14% or less, 13% or less, 12% or less, 11% or less, 10% or less, and 9% or less in that order, and particularly 8% or less. In the present embodiment, with a view to improving meltability at high temperatures or glass strength, the B₂O₃ content is, for example, preferably 0.5% or more, more preferably 1% or more, even more preferably 2% or more, particularly preferably 3% or more, and particularly 4% or more.

[0079] Al₂O₃ is a component that improves the mechanical properties of glass, such as the Young's modulus and the fracture toughness, and enhances the glass's weather resistance. Furthermore, when added together with CeO₂, Al₂O₃ also improves devitrification resistance. In the first and fifth embodiments, the Al2O3 content is preferably 0% to 30%. In the second to fourth embodiments, the Al2O3 content is 0% to 30%. If Al2O3 is 30% or less, an increase in T2 or T4 can be prevented and the meltability or malleability of the glass can be improved. In the first to fifth embodiments, in the case where Al2O3 is included, preferably 1% or more, more preferably 2% or more, even more preferably 4% or more and particularly preferably 5% or more, 5.5% or more, 6% or more, 6.5% or more, 7% or more, 7.5% or more, 8% or more and 9% or more in that order. In the first and fifth embodiments, the Al2O3 content is more preferably 25% or less, and even more preferably 20% or less. If the Al2O3 content is 30% or less, an increase in T2 or T4 can be prevented, and the meltability or formability of the glass can be improved.

[0080] In the second to fourth embodiments, the Al2O3 content is preferably 25% or less, more preferably 23% or less and even more preferably 20% or less.

[0081] As₂O₃ is a component that promotes solarization and is an optional component. In the present embodiment, the As₂O₃ content is preferably 0.25% or less, more preferably 0.10% or less, and even more preferably 0.05% or less, with regard to preventing solarization and with regard to the SDGs. The lower limit of the As₂O₃ content is not specifically limited, and if it is included, it is preferably 0.001% or more with regard to the refining properties.

[0082] Sb₂O₃ is a component that acts as a refining agent. In the present embodiment, the Sb₂O₃ content is preferably 0.25% or less with regard to the SDGs, more preferably 0.2% or less, and even more preferably 0.1% or less. The lower limit of the Sb₂O₃ content is not specifically restricted, and if it is included, it is preferably 0.001% or more with regard to the refining properties.

[0083] In the present embodiment, the total content of As2O3 and Sb2O3 with respect to the SDGs is preferably 0% or more and less than 0.25%, more preferably 0% or more and 0.2% or less, even more preferably 0% or more and 0.1% or less, and particularly preferably 0% or more and 0.05% or less.

[0084] SnO2 is a component that prevents solarization. In the present embodiment, the SnO2 content is preferably 0.01% or more and 0.4% or less. In the present embodiment, with a view to better preventing solarization, the SnO2 content is more preferably 0.02% or more, even more preferably 0.05% or more, and particularly preferably 0.1% or more. Furthermore, with a view to preventing a decrease in devitrification resistance, the SnO2 content is more preferably 0.3% or less and even more preferably 0.2% or less.

[0085] Fe₂O₃ is an optional component, but may be included to improve the ultraviolet radiation shielding effect and prevent staining caused by the electron beam. However, it also reduces the transmittance from the visible to the near-infrared range, thus decreasing cell efficiency. In the present embodiment, the Fe₂O₃ content is preferably 3% or less, and more preferably 2% or less, 1.5% or less, 1% or less, 0.8% or less, 0.6% or less, 0.4% or less, 0.2% or less, 0.1% or less, 0.09% or less, 0.08% or less, 0.07% or less, 0.06% or less, 0.05% or less, 0.04% or less, 0.03% or less, 0.02% or less, or 0.01% or less.Furthermore, the lower limit of its content is not specifically restricted and, with regard to the ultraviolet radiation shielding effect and the prevention of staining due to an electron beam, is preferably 0.001% or more, and more preferably 0.002% or more, 0.003% or more, or 0.004% or more, in the case where it is present. If the Fe₂O₃ content is 0.001% or more, the ultraviolet radiation shielding effect can be ensured and staining due to an electron beam can be better prevented. If the Fe₂O₃ content is 3% or less, the transmittance to visible light can be increased.

[0086] In the case where the glass contains CeO2 according to the present embodiment, the value of Y, represented by the following equation, is preferably 0 or more and 1300 or less with a view to further improving the ultraviolet radiation shielding effect and establishing a redox state of Ce. The value of Y is more preferably 1200 or less, even more preferably 1000 or less, and particularly preferably 800 or less. The value of Y is more preferably 100 or more, even more preferably 300 or more, and particularly preferably 500 or more. Y=[CeO2] / [Fe2O3]

[0087] In the equation, the brackets [] represent the content as mass % based on oxides.

[0088] MgO is an optional component that prevents a reduction in strength or improves meltability. In the present embodiment, if MgO is included, its content is preferably 0.5% or more, more preferably 1.0% or more, even more preferably 1.5% or more, and particularly preferably 2.0% or more. In the present embodiment, the MgO content is preferably 13% or less, more preferably 12.5% ​​or less, even more preferably 12% or less, and particularly preferably 11.5% or less, 11% or less, 10.5% or less, 10% or less, 9.5% or less, 9% or less, 8.5% or less, 8% or less, 7.5% or less, and 7% or less in that order.

[0089] BaO is a component that improves meltability at high temperatures or makes devitrification less likely and may be included. In the present embodiment, the BaO content is preferably 0% or more and 6.5% or less. Where BaO is included, its content is more preferably 0.5% or more, more preferably 1.0% or more, and particularly preferably 1.5% or more. To prevent an increase in relative density, the BaO content is more preferably 5.0% or less, more preferably 4.0% or less, and particularly preferably 3.0% or less.

[0090] CaO may be included to improve meltability at high temperatures or to reduce the likelihood of devitrification. In the present embodiment, if CaO is included, its content is preferably 0.5% or more, more preferably 1.0% or more, even more preferably 1.5% or more, and particularly preferably 2.0% or more. In the present embodiment, the CaO content is preferably 13% or less, more preferably 12.5% ​​or less, even more preferably 12% or less, and particularly preferably 11.5% or less, 11% or less, 10.5% or less, 10% or less, 9.5% or less, 9% or less, 8.5% or less, 8% or less, 7.5% or less, and 7% or less in that order.

[0091] SrO can be included to improve meltability at high temperatures or to reduce the likelihood of devitrification. In the present embodiment, if SrO is included, its content is more preferably 0.5% or more, more preferably 1.0% or more, and particularly preferably 1.5% or more. To prevent an increase in relative density, the SrO content is preferably 8% or less, more preferably 6% or less, more preferably 4% or less, particularly preferably 2% or less, and especially 0.1% or less.

[0092] In the present embodiment, in the case where at least one selected from the group consisting of BaO, CaO and SrO is included, the total content of these three components is preferably 10% or less and more preferably 8% or less, 6% or less, 4% or less or 2% or less.

[0093] With a view to increasing transmittance at wavelengths from 300 nm to 1100 nm and improving the cell efficiency of the solar cell, it is preferred that the glass be essentially free of NiO. In the present embodiment, if NiO is present, its content is preferably 1% or less, more preferably 0.5% or less, even more preferably 0.1% or less, and still more preferably 0.08% or less.

[0094] ZrO2 is not an essential component, but may be included in a concentration of 1.6% or less, among other reasons, to reduce viscosity at high temperatures or to improve long-term chemical resistance. In the present embodiment, a reduction in strength can be prevented if the ZrO2 content is 1.6% or less. The ZrO2 content is more preferably 1.5% or less, even more preferably 1.4% or less, particularly preferably 1.3% or less, and especially 1.1% or less.

[0095] ZnO may be included to improve the meltability of the glass at high temperatures, and in this case, its content is preferably 1% or less, more preferably 0.5% or less, and even more preferably 0.25% or less. When the glass is produced using a float process, the ZnO content is preferably 0.5% or less, more preferably 0.25% or less, and the glass is even more preferably essentially free of ZnO, with the ZnO content being particularly 0%. If the ZnO content is 1% or less, reduction during float forming can be prevented, and the generation of product defects can be avoided.

[0096] V₂O₅ may be included to improve the ultraviolet radiation shielding effect. In the case where V₂O₅ is included, its content, with a view to further improving the ultraviolet radiation shielding effect, is preferably 0.01% or more, more preferably 0.05% or more, even more preferably 0.1% or more, and particularly preferably 0.2% or more. Conversely, in the case where V₂O₅ is included, its content, with a view to preventing staining, is preferably 1.0% or less, more preferably 0.8% or less, even more preferably 0.6% or less, and particularly preferably 0.4% or less.

[0097] SO3, a chloride, and a fluoride can be included in a suitable manner as refining agents during the melting of the glass. However, to improve the cell efficiency of the solar cell when the glass is used as a solar cell cover glass, it is preferred to reduce as much as possible the amount of components such as Cr2O3 with an absorption in a wavelength range of 300 nm to 1100 nm, which are mixed into the starting material as impurities. If the component is included, it is preferably 0.15% or less, more preferably 0.1% or less, and particularly preferably 0.05% or less.

[0098] Examples of an aspect of the glass according to the first embodiment include the following aspects (1a) to (1c). (1a) An aspect in which the total content of Li2O, Na2O and K2O is 0% to 3.5% and CeO2 is present in an amount of 0.1% to 10%, as mass % based on oxides. (1b) An aspect in which the total content of Li2O, Na2O and K2O is 0% to 3.5%, CeO2 is present in an amount of 0.1% to 10% and TiO2 is present in an amount of 5% to 10%, as mass % based on oxides. (1c) An aspect in which the total content of Li2O, Na2O and K2O is 0% to 3.5%, CeO2 is present in an amount of 0.1% to 10% and TiO2 is present in an amount of 0.01% to 10%.

[0099] Specific examples of the composition of the glass according to the present embodiment include the following. (1) A glass containing 50% to 80% SiO2, 0% to 25% B2O3, 0% to 30% Al2O3, 0.1% to 10% CeO2 and 0% to 3.5% R2O as mass percent based on oxides. (2) A glass containing 50% to 80% SiO2, 0% to 25% B2O3, 0% to 30% Al2O3, 5% to 10% TiO2 and 0% to 3.5% R2O as mass percent based on oxides. (3) A glass containing 50% to 80% SiO2, 0% to 25% B2O3, 0% to 30% Al2O3, 0.01% to 10% TiO2, 0.1% to 10% CeO2 and 0% to 3.5% R2O as mass percent based on oxides. <Verfahren zur Herstellung eines Glases>

[0100] The glass according to the present embodiment can be produced by a general method. For example, starting materials of the glass components are mixed and then heated and melted in a glass melting furnace. Afterwards, the glass is homogenized using a known method and formed into a desired shape, such as a glass sheet, after which it is tempered.

[0101] Examples of forming processes for a glass sheet include the float process, the press process, the fusing process, and the down-draw process. In particular, the float process is preferred, as it is suitable for mass production. As continuous forming processes different from the float process, the fusing process and the down-draw process are also preferred.

[0102] The molten glass then undergoes grinding, polishing, and etching to form a glass substrate. The thickness of the glass substrate can be adjusted to a desired thickness based on the treatment conditions. Specific examples of etching include polishing the glass surface by immersing the glass substrate in a solution containing hydrofluoric acid or similar substances, followed by etching.

[0103] The glass according to the present embodiment preferably comprises a conductive film on at least one surface. Examples of components of the conductive film include In₂O₃, SnO₂, and ZnO. The thickness of the conductive film is preferably 10,000 nm or less, and more preferably 80,000 nm or less, 50,000 nm or less, 10,000 nm or less, 5,000 nm or less, 1,000 nm or less, 500 nm or less, or 100 nm or less. The lower limit of the thickness is not specifically defined and is, for example, 1 nm or more, and more preferably 5 nm or more, or 10 nm or more.

[0104] The glass according to the present embodiment preferably comprises an anti-reflective film on at least one surface. Examples of components of the anti-reflective film include MgF₂, CrNi, Ag, SiO₂. X , TiO X , Ta2O5 and Al2O3.

[0105] The anti-reflective film is not limited to a single layer and can be a multilayer in which several components are combined. The thickness of the anti-reflective film is preferably 10,000 nm or less, and more preferably 80,000 nm or less, 50,000 nm or less, 10,000 nm or less, 5,000 nm or less, 1,000 nm or less, 500 nm or less, or 100 nm or less. The lower limit of the thickness is not specifically defined and is, for example, 1 nm or more, and more preferably 5 nm or more, or 10 nm or more. <anwendung>

[0106] The glass according to the present embodiment is advantageously used as a solar cell cover glass (for example, a solar cell cover glass for a space satellite), an electron beam shielding glass, and a UV-blocking glass. The glass according to the present embodiment exhibits excellent electron beam resistance and ultraviolet radiation shielding, possesses excellent strength, and its size can be increased compared to those of the prior art, and is therefore better suited as a solar cell cover glass, which must possess these properties. EXAMPLES The present invention is described in detail below with reference to examples, however the present invention is not limited thereto. (Manufacturing the glass)

[0107] Commonly used glass starting materials, such as oxides, hydroxides, carbonates, or nitrates, were selected to obtain glasses exhibiting the compositions shown in Tables 1 to 6, as indicated in the tables as mass percent based on oxides. These glasses were placed in a platinum crucible and melted in an electric furnace by heating to a high temperature of 1550 °C to 1650 °C or higher. The molten glass was then poured onto a carbon mold and held at Tg + 50 °C for 1 hour. It was then cooled at a rate of 1.0 °C / min to obtain a glass block. The resulting glass block was cut, ground, and polished to produce a glass sample of a predetermined size, and its physical properties were evaluated. (Evaluation of characteristics)

[0108] The properties of the obtained glass substrate were evaluated by the following procedures. [Relative density]

[0109] The relative density was measured using the Archimedes method. [Young's module]

[0110] The Young's modulus was measured using the ultrasonic pulse method (JIS R1602, 1995). A glass substrate measuring 30 mm length × 30 mm width × 1 mm thickness was used for the measurement. [Average coefficient of thermal expansion CTE (50 to 200) [ppm / K]]

[0111] The average coefficient of thermal expansion was measured using a differential thermal expansion gauge according to a procedure specified in JIS R3102 (1995). The measurement temperature range was 50 °C to 200 °C and the unit was [× 10⁻⁵]. -6 / K]. A glass substrate measuring 25 mm in length × 6 mm in width × 0.8 mm in thickness was used in the measurement. (β-OH)

[0112] The transmittance of the glass sample was measured using FT-IR, and β-OH was determined using the following equation. A glass substrate measuring 30 mm length × 30 mm width × 1 mm thickness was used in the measurement. β−OH=(1X)log10(T1T2) X: Thickness (mm) of the glass T1: Transmittance (%) at a reference wavelength of 3846 cm -1 T2: Minimum transmittance (%) near a hydroxyl group absorption wavelength of 3600 cm⁻¹ -1 [K IC ]

[0113] The “fracture toughness value” can be measured using a DCDC method (Acta metall. mater., Volume 43, pages 3453-3458, 1995). [Permeability]

[0114] The transmittance was measured using a spectrophotometer (trade name: U-4100) manufactured by Hitachi High-Tech Corporation. Glass substrates measuring 25 mm length × 25 mm width × 100 µm thickness and 25 mm length × 25 mm width × 50 µm thickness were used in the measurements.

[0115] [Average extinction change magnitude in the wavelength range from 400 nm to 800 nm during electron beam irradiation (based on a thickness of 100 µm)]

[0116] In electron beam irradiation, a glass substrate to be irradiated was placed horizontally on a table and the glass substrate was irradiated with an electron beam of 1 × 10 15 electrons / cm 2 The glass substrate was irradiated with an energy of 1 MeV using an electron beam irradiation device (model number: EPS-3000 kV, manufactured by NHV Corporation). The measurement used a glass substrate measuring 20 mm length × 20 mm width × 0.5 mm thickness. The transmittance was measured before electron beam irradiation and again after each glass substrate had been irradiated. The measurement was performed within one week of electron beam irradiation. The absorbance before and after electron beam irradiation was calculated based on the measured transmittance and converted to the absorbance at a thickness of 100 µm. The average magnitude of the absorbance change in the wavelength range from 400 nm to 800 nm was then calculated according to the following equation. ∑λ=400800(Anach[λ]−Avor[λ])400 A [λ]: Extinction at wavelength λ A nach [λ]: Extinction at wavelength λ before electron beam irradiation A vor [λ]: Extinction at wavelength λ after electron beam irradiation [Extent of delay]

[0117] For the glass in each example, the degree of distortion was calculated based on a bimetallic distortion calculation, which is defined according to the following equation. In particular, the absolute value of the degree of distortion δ was calculated according to the following equation. δ=6L2(α1−α1)(T2−T1)(1+m)28h[3(1+m)2+(1+nm){m2+(mm)−1}] L: Length [mm] in the direction of distortion of the glass α1: Coefficient of thermal expansion [ppm / K] of the solar cell α2: Coefficient of thermal expansion [ppm / K] of the glass E1: Young's modulus [GPa] of the solar cell E2: Young's modulus [GPa] of the glass T1: Assumed maximum temperature (°C) T2: Assumed minimum temperature (°C) a1: Thickness [mm] of the solar cell a2: Thickness [mm] of the glass h: a1 + a2 [mm] m: a1 / a2 n: E1 / E2 δ: Deformation dimension [mm]

[0118] It was assumed that the solar cell used was monocrystalline silicon manufactured by Sunpower as "MAXEON™ GENIII SOLAR CELLS". Therefore, the coefficient of thermal expansion and the Young's modulus of the solar cell were α1 = 3.2 ppm / °C and E1 = 190 GPa, respectively, assuming monocrystalline silicon. The coefficient of thermal expansion of the glass was determined to be an average value (ppm / °C) within a range of 50°C to 200°C. The thickness of the solar cell was assumed to be 0.15 mm.

[0119] Tables 1 to 6 show the glass composition as mass percent based on oxides and the results of the property evaluation. Fig. Figure 1 is a diagram showing the correlation between the average coefficient of thermal expansion and (absolute value of the distortion δ / length in the distortion direction of the glass).

[0120] In Tables 1 to 6, Examples 1 to 39 are examples according to the invention, and Examples 40 to 42 are comparative examples. In Tables 1 to 6, an entry in italics indicates a calculated value, and a dash (-) indicates that no evaluation is performed.

[0121] In the case of considering the transmittance at 50 µm based on the transmittance at 100 µm, the transmittance can be calculated according to the Lambert-Beer law, assuming that the amount of the light-absorbing element is half. [Table 1] Example 1 2 3 4 5 6 7 SiO2 61,0 57,3 59,1 58,2 56,6 56,9 56,5 Al2O3 12,6 17,3 17,8 16,9 17,1 16,6 17,0 B2O3 4,4 12,1 11,9 12,5 11,9 11,8 12,4 MgO 8,8 1,2 1,2 1,1 1,2 1,2 1,2 CaO 4,5 6,4 6,9 6,5 6,4 6,2 6,3 SrO 3,8 0,9 0,8 0,7 0,9 0,9 0,9 BaO 0,0 0,0 0,0 0,0 0,0 0,0 0,0 Li2O 0,0 0,0 0,0 0,0 0,0 0,0 0,0 Na2O 0,05 0,06 0,06 0,04 0,48 0,88 0,05 K2O 0,01 0,01 0,01 0,01 0,46 0,88 0,01 ZrO2 0,0 0,0 0,0 0,0 0,0 0,0 0,0 TiO2 2,8 2,7 0,0 0,0 2,8 2,7 5,5 CeO2 1,8 1,8 2,0 3,7 1,8 1,8 0,0 Fe2O3 0,005 0,004 0,011 0,010 0,005 0,005 0,005 SnO2 0,2 0,2 0,2 0,2 0,2 0,2 0,2 SO3 0,021 0,008 0,028 0,012 0,006 0,005 0,011 Cl 0,02 0,01 0,0 0,0 0,0 0,0 0,01 In total 100,0 100,0 100,0 100,0 100,0 100,0 100,0 Li2O + Na2O + K2O 0,1 0,1 0,1 0,0 0,9 1,8 0,1 CeO2 / Fe2O3 371 408 172 372 379 396 0 5CeO2 + TiO2 11,6 11,7 9,8 18,5 11,9 11,7 5,5 Relative density ρ 2,59 2,45 2,42 2,46 2,45 2,45 2,41 Young's modulus E [GPa] 89,2 75,5 74,7 76,3 75,9 76,2 74,8 E / p [GPa] 34,4 30,9 30,9 31,1 31,1 31,0 31,0 CTE (50 °C to 200 °C) [ppm / K] 4,04 3,32 3,25 3,41 3,61 3,92 3,24 β-OH [mm -1 ] 0,14 0,21 0,18 0,21 0,14 0,18 0,16 Average extinction change magnitude in a wavelength range from 400 nm to 800 nm during electron beam irradiation [based on a thickness of 100 µm] 0,003 0,003 0,003 0,002 0,003 0,003 - K IC [MPa m 1 / 2 ] 0,83 0,86 0,85 0,85 0,86 0,85 0,87 Transmittance at 100 µm at a wavelength of 400 nm 81 88 91 91 87 85 90 Transmittance at 100 µm at a wavelength of 300 nm 0 2 3 0 1 1 0 Transmittance at 100 µm ([at a wavelength of 400] - [at a wavelength of 300 nm]) 81 87 89 91 86 84 90 Wavelength [nm] at which a transmittance of 50% is achieved with a thickness of 100 µm 344 333 - - 336 338 325 Transmittance at 50 µm [at a wavelength of 400 nm] 88 90 92 91 89 89 91 Transmittance at 50 µm [at a wavelength of 300 nm] 3 4 16 2 3 3 5 Transmittance at 50 µm ([at a wavelength of 400] - [at a wavelength of 300 nm]) 86 87 76 89 87 86 86 Wavelength [nm] at which a transmittance of 50% is achieved with a thickness of 50 µm 329 325 319 327 327 328 318 Absolute value of the distortion extent δ / length in the distortion direction of the glass (length in the distortion direction: 1000 mm, thickness: 0.1 mm) 0,14 0,02 0,00 0,03 0,06 0,11 0,00 Absolute value of the distortion δ / length in the distortion direction of the glass (length in the distortion direction: 1000 mm, thickness: 0.05 mm) 0,11 0,01 0,00 0,02 0,05 0,09 0,00 Absolute value of the degree of distortion δ / length in the distortion direction of the glass (length in the distortion direction: 500 mm, thickness: 0.1 mm) 0,07 0,01 0,00 0,01 0,03 0,06 0,00 Absolute value of the distortion extent δ / length in the distortion direction of the glass (length in the distortion direction: 500 mm, thickness: 0.05 mm) 0,06 0,01 0,00 0,01 0,02 0,04 0,00 [Table 2] Example 8 9 10 11 12 13 14 SiO2 59,6 58,4 56,5 56,5 56,5 55,9 58,4 Al2O3 17,5 17,2 16,3 16,3 16,3 16,2 18,9 B2O3 12,0 11,8 7,7 7,7 7,7 7,6 1,2 MgO 1,1 1,1 2,9 2,9 2,9 2,9 5,3 CaO 6,7 6,6 3,6 3,6 3,6 3,6 4,4 SrO 0,9 0,9 7,7 7,7 7,7 7,6 6,6 BaO 0,0 0,0 0,0 0,0 0,0 0,0 0,1 Li2O 0,0 0,0 0,0 0,0 0,0 0,0 0,0 Na2O 0,06 0,06 0,0 0,0 0,5 1 0,0 K2O 0,01 0,01 0,0 0,0 0,5 1 0,0 ZrO2 0,0 0,0 0,0 0,0 0,0 0,0 0,0 TiO2 0,0 0,0 2,0 1,0 1,0 1,0 1,0 CeO2 1,9 3,7 3,0 4,0 3,0 3,0 4,0 Fe2O3 0,004 0,005 0,005 0,005 0,005 0,005 0,005 SnO2 0,0 0,0 0,2 0,2 0,2 0,2 0,2 SO3 0,011 0,014 0,0 0,0 0,0 0,0 0,0 Cl 0,15 0,16 0,0 0,0 0,0 0,0 0,0 In total 100,0 100,0 100,0 100,0 100,0 100,0 100,0 Li2O + Na2O + K2O 0,1 0,1 0,0 0,0 1,0 2,0 0,0 CeO2 / Fe2O3 433 731 600 800 600 600 800 5CeO2 + TiO2 9,4 18,7 17,0 21,0 16,0 16,0 21,0 Relative density ρ 2,42 2,46 2,58 2,59 2,58 2,58 2,67 Young's modulus E [GPa] 74,6 75,6 77,7 78,1 77,9 78,3 88,1 E / p [GPa] 30,9 30,8 30,1 30,1 30,3 30,3 33,0 CTE (50 °C to 200 °C) [ppm / K] 3,32 3,41 3,77 3,82 4,07 4,37 3,85 β-OH [mm -1 ] 0,17 0,18 - - - - - Average extinction change magnitude in a wavelength range from 400 nm to 800 nm during electron beam irradiation [based on a thickness of 100 µm] 0,002 0,001 0,003 0,002 0,003 0,003 0,002 K IC [MPa m 1 / 2 ] 0,85 0,85 0,84 0,83 0,83 0,83 0,81 Transmittance at 100 µm at a wavelength of 400 nm 90 88 89 88 87 85 84 Transmittance at 100 µm at a wavelength of 300 nm 2 0 0 0 0 0 0 Transmittance at 100 µm ([at a wavelength of 400] - [at a wavelength of 300 nm]) 88 88 89 88 87 85 84 Wavelength [nm] at which a transmittance of 50% is achieved with a thickness of 100 µm - - - - - - - Transmittance at 50 µm [at a wavelength of 400 nm] 91 90 90 90 89 88 88 Transmittance at 50 µm [at a wavelength of 300 nm] 10 1 2 1 2 2 1 Transmittance at 50 µm ([at a wavelength of 400] - [at a wavelength of 300 nm]) 81 89 88 89 87 86 87 Wavelength [nm] at which a transmittance of 50% is achieved with a thickness of 50 µm 323 333 330 332 330 332 335 Absolute value of the distortion extent δ / length in the distortion direction of the glass (length in the distortion direction: 1000 mm, thickness: 0.1 mm) 0,02 0,03 0,09 0,10 0,14 0,19 0,11 Absolute value of the distortion δ / length in the distortion direction of the glass (length in the distortion direction: 1000 mm, thickness: 0.05 mm) 0,01 0,02 0,07 0,08 0,11 0,15 0,09 Absolute value of the degree of distortion δ / length in the distortion direction of the glass (length in the distortion direction: 500 mm, thickness: 0.1 mm) 0,01 0,01 0,05 0,05 0,07 0,09 0,05 Absolute value of the distortion extent δ / length in the distortion direction of the glass (length in the distortion direction: 500 mm, thickness: 0.05 mm) 0,01 0,01 0,04 0,04 0,06 0,07 0,04 [Table 3] Example 15 16 17 18 19 20 21 SiO2 58,4 57,7 58,9 58,3 55,5 54,9 54,4 Al2O3 18,9 18,7 19,5 19,3 17,9 17,7 17,5 B2O3 1,2 1,2 4,7 4,7 9,7 9,6 9,5 MgO 5,3 5,3 4,7 4,7 2,6 2,6 2,6 CaO 4,4 4,3 5,4 5,4 1,6 1,6 1,5 SrO 6,6 6,5 1,5 1,5 7,5 7,4 7,3 BaO 0,1 0,1 0,0 0,0 0,0 0,0 0,0 Li2O 0,0 0,0 0,0 0,0 0,0 0,0 0,0 Na2O 0,5 1 1 1,5 0,0 1 1,5 K2O 0,5 1 1 1,5 0,0 1 1,5 ZrO2 0,0 0,0 0,0 0,0 0,0 0,0 0,0 TiO2 1,0 1,0 1,0 1,0 2,0 1,0 1,0 CeO2 3,0 3,0 2,0 2,0 3,0 3,0 3,0 Fe2O3 0,005 0,005 0,005 0,005 0,005 0,005 0,005 SnO2 0,2 0,2 0,2 0,2 0,2 0,2 0,2 SO3 0,0 0,0 0,0 0,0 0,0 0,0 0,0 Cl 0,0 0,0 0,0 0,0 0,0 0,0 0,0 In total 100,0 100,0 100,0 100,0 100,0 100,0 100,0 Li2O + Na2O + K2O 1,0 2,0 2,0 3,0 0,0 2,0 3,0 CeO2 / Fe2O3 600 600 400 400 600 600 600 5CeO2 + TiO2 16,0 16,0 11,0 11,0 17,0 16,0 16,0 Relative density ρ 2,66 2,66 2,52 2,53 2,53 2,53 2,53 Young's modulus E [GPa] 87,9 88,3 86,4 86,7 77,4 77,6 78,0 E / p [GPa] 33,1 33,2 34,3 34,3 30,6 30,7 30,8 CTE (50 °C to 200 °C) [ppm / K] 4,10 4,40 3,92 4,22 3,31 3,61 3,91 β-OH [mm -1 ] - - - - - - - Average extinction change magnitude in a wavelength range from 400 nm to 800 nm during electron beam irradiation [based on a thickness of 100 µm] 0,003 0,003 0,003 0,003 0,003 0,003 0,003 K IC [MPa m 1 / 2 ] 0,81 0,81 0,83 0,82 0,85 0,84 0,83 Transmittance at 100 µm at a wavelength of 400 nm 83 81 85 83 89 85 83 Transmittance at 100 µm at a wavelength of 300 nm 0 0 0 0 0 0 0 Transmittance at 100 µm ([at a wavelength of 400] - [at a wavelength of 300 nm]) 83 81 85 83 89 85 83 Wavelength [nm] at which a transmittance of 50% is achieved with a thickness of 100 µm - - - - - - - Transmittance at 50 µm [at a wavelength of 400 nm] 87 86 88 87 90 88 87 Transmittance at 50 µm [at a wavelength of 300 nm] 2 1 5 4 2 2 2 Transmittance at 50 µm ([at a wavelength of 400] - [at a wavelength of 300 nm]) 85 84 84 83 88 86 85 Wavelength [nm] at which a transmittance of 50% is achieved with a thickness of 50 µm 333 335 328 330 330 332 334 Absolute value of the distortion extent δ / length in the distortion direction of the glass (length in the distortion direction: 1000 mm, thickness: 0.1 mm) 0,15 0,20 0,12 0,17 0,01 0,06 0,11 Absolute value of the distortion δ / length in the distortion direction of the glass (length in the distortion direction: 1000 mm, thickness: 0.05 mm) 0,12 0,16 0,10 0,14 0,01 0,05 0,09 Absolute value of the degree of distortion δ / length in the distortion direction of the glass (length in the distortion direction: 500 mm, thickness: 0.1 mm) 0,07 0,170 0,06 0,08 0,01 0,03 0,06 Absolute value of the distortion extent δ / length in the distortion direction of the glass (length in the distortion direction: 500 mm, thickness: 0.05 mm) 0,06 0,08 0,05 0,07 0,01 0,02 0,04 [Table 4] Example 22 23 24 25 26 27 28 SiO2 55,9 57,7 54,9 55,9 56,5 52,6 59,6 Al2O3 16,2 18,7 17,7 16,2 18,3 17,0 17,5 B2O3 7,6 1,2 9,6 7,6 1,2 9,2 11,9 MgO 2,9 5,3 2,6 2,9 5,1 2,5 1,1 CaO 3,6 4,3 1,6 3,6 4,2 1,5 6,6 SrO 7,6 6,5 7,4 7,6 6,4 7,1 1,0 BaO 0,0 0,1 0,0 0,0 0,1 0,0 0,0 Li2O 0,0 0,0 0,0 0,0 0,0 0,0 0,0 Na2O 0,0 0,0 0,0 0,0 0,0 0,0 0,0 K2O 0,0 0,0 0,0 0,0 0,0 0,0 0,0 ZrO2 0,0 0,0 0,0 0,0 0,0 0,0 0,0 TiO2 0,0 0,0 0,0 6,0 8,0 10,0 1,0 CeO2 6,0 6,0 6,0 0,0 0,0 0,0 1,0 Fe2O3 0,005 0,005 0,005 0,005 0,005 0,005 0,005 SnO2 0,2 0,2 0,2 0,2 0,2 0,2 0,2 SO3 0,0 0,0 0,0 0,0 0,0 0,0 0,0 Cl 0,0 0,0 0,0 0,0 0,0 0,0 0,0 In total 100,0 100,0 100,0 100,0 100,0 100,0 99,9 Li2O + Na2O + K2O 0,0 0,0 0,0 0,0 0,0 0,0 0,0 CeO2 / Fe2O3 1200 1200 1200 0 0 0 200 5CeO2 + TiO2 30,0 30,0 30,0 6,0 8,0 10,0 6,0 Relative density ρ 2,62 2,70 2,57 2,54 2,64 2,52 2,40 Young's modulus E [GPa] 79,0 89,0 78,7 76,6 86,8 76,7 74,9 E / p [GPa] 30,71 32,9 30,6 30,1 32,9 30,5 31,2 CTE (50 °C to 200 °C) [ppm / K] 3,91 3,94 3,45 3,65 3,68 3,20 3,27 β-OH [mm -1 ] - - - - - - - Average extinction change magnitude in a wavelength range from 400 nm to 800 nm during electron beam irradiation [based on a thickness of 100 µm] 0,001 0,001 0,001 - - - 0,005 K IC [MPa m 1 / 2 ] 0,83 0,81 0,85 0,84 0,83 0,87 0,85 Transmittance at 100 µm at a wavelength of 400 nm 87 83 87 90 90 90 90 Transmittance at 100 µm at a wavelength of 300 nm 0 0 0 0 0 0 4 Transmittance at 100 µm ([at a wavelength of 400] - [at a wavelength of 300 nm]) 87 83 87 90 90 90 86 Wavelength [nm] at which a transmittance of 50% is achieved with a thickness of 100 µm - - - - - - Transmittance at 50 µm [at a wavelength of 400 nm] 89 87 89 91 91 90 91 Transmittance at 50 µm [at a wavelength of 300 nm] 0 0 0 4 1 1 20 Transmittance at 50 µm ([at a wavelength of 400] - [at a wavelength of 300 nm]) 89 87 89 87 89 90 71 Wavelength [nm] at which a transmittance of 50% is achieved with a thickness of 50 µm 337 339 337 319 322 325 317 Absolute value of the distortion extent δ / length in the distortion direction of the glass (length in the distortion direction: 1000 mm, thickness: 0.1 mm) 0,11 0,12 0,04 0,07 0,08 0,01 0,01 Absolute value of the distortion δ / length in the distortion direction of the glass (length in the distortion direction: 1000 mm, thickness: 0.05 mm) 0,09 0,10 0,03 0,05 0,06 0,00 0,01 Absolute value of the degree of distortion δ / length in the distortion direction of the glass (length in the distortion direction: 500 mm, thickness: 0.1 mm) 0,06 0,06 0,02 0,03 0,04 0,00 0,00 Absolute value of the distortion extent δ / length in the distortion direction of the glass (length in the distortion direction: 500 mm, thickness: 0.05 mm) 0,04 0,05 0,01 0,03 0,03 0,00 0,00 [Table 5] Example 29 30 31 32 33 34 35 SiO2 59,0 59,0 57,8 58,4 56,6 57,8 56,6 Al2O3 17,3 17,3 17,0 17,1 16,6 17,0 16,6 B2O3 11,8 11,8 11,5 11,7 11,3 11,5 11,3 MgO 1,1 1,1 1,1 1,1 1,1 1,1 1,1 CaO 6,6 6,6 6,4 6,5 6,3 6,4 6,3 SrO 0,9 0,9 0,9 0,9 0,9 0,9 0,9 BaO 0,0 0,0 0,0 0,0 0,0 0,0 0,0 Li2O 0,0 0,0 0,0 0,0 0,0 0,0 0,0 Na2O 0,5 0,0 1 0,0 1,5 0,0 1 K2O 0,5 0,0 1 0,0 1,5 0,0 1 ZrO2 0,0 0,0 0,0 0,0 0,0 0,0 0,0 TiO2 1,0 2,0 2,0 3,0 3,0 4,0 4,0 CeO2 1,0 1,0 1,0 1,0 1,0 1,0 1,0 Fe2O3 0,005 0,005 0,005 0,005 0,005 0,005 0,005 SnO2 0,2 0,2 0,2 0,2 0,2 0,2 0,2 SO3 0,0 0,0 0,0 0,0 0,0 0,0 0,0 Cl 0,0 0,0 0,0 0,0 0,0 0,0 0,0 In total 99,9 99,9 99,9 99,9 99,9 99,9 99,9 Li2O + Na2O + K2O 1,0 0,0 2,0 0,1 3,0 0,1 2,0 CeO2 / Fe2O3 200 200 200 200 200 200 200 5CeO2 + TiO2 6,0 7,0 7,0 8,0 8,0 9,0 9,0 Relative density ρ 2,41 2,41 2,42 2,41 2,43 2,42 2,43 Young's modulus E [GPa] 75,2 75,0 75,7 75,1 76,1 75,2 75,9 E / ρ [GPa] 31,3 31,1 31,3 31,1 31,4 31,1 31,3 CTE (50 °C to 200 °C) [ppm / K] 3,57 3,28 3,87 3,28 4,18 3,28 3,88 β-OH [mm -1 ] - - - - - - - Average extinction change magnitude in a wavelength range from 400 nm to 800 nm during electron beam irradiation [based on a thickness of 100 µm] 0,005 0,003 0,003 0,003 0,003 0,002 0,002 K IC [MPa m 1 / 2 ] 0,85 0,85 0,85 0,86 0,84 0,86 0,85 Transmittance at 100 µm at a wavelength of 400 nm 88 90 86 90 84 90 86 Transmittance at 100 µm at a wavelength of 300 nm 3 2 1 1 0 0 0 Transmittance at 100 µm ([at a wavelength of 400] - [at a wavelength of 300 nm]) 85 89 85 90 84 90 86 Wavelength [nm] at which a transmittance of 50% is achieved with a thickness of 100 µm - - - - - Transmittance at 50 µm [at a wavelength of 400 nm] 90 91 89 91 87 91 88 Transmittance at 50 µm [at a wavelength of 300 nm] 16 12 8 7 4 4 3 Transmittance at 50 µm ([at a wavelength of 400] - [at a wavelength of 300 nm]) 73 79 80 84 83 86 86 Wavelength [nm] at which a transmittance of 50% is achieved with a thickness of 50 µm 319 319 323 321 327 322 326 Absolute value of the distortion extent δ / length in the distortion direction of the glass (length in the distortion direction: 1000 mm, thickness: 0.1 mm) 0,06 0,01 0,11 0,01 0,16 0,01 0,11 Absolute value of the distortion δ / length in the distortion direction of the glass (length in the distortion direction: 1000 mm, thickness: 0.05 mm) 0,04 0,01 0,08 0,01 0,12 0,01 0,08 Absolute value of the degree of distortion δ / length in the distortion direction of the glass (length in the distortion direction: 500 mm, thickness: 0.1 mm) 0,03 0,00 0,05 0,00 0,08 0,00 0,05 Absolute value of the distortion extent δ / length in the distortion direction of the glass (length in the distortion direction: 500 mm, thickness: 0.05 mm) 0,02 0,00 0,04 0,00 0,06 0,00 0,04 [Table 6] Example 36 37 38 39 40 41 42 SiO2 58,4 56,6 55,3 55,3 69,2 61,0 61,1 Al2O3 17,1 16,6 16,3 16,3 5,2 14,0 6,9 B2O3 11,7 11,3 11,1 11,1 0,0 5,3 11,3 MgO 1,1 1,1 1,0 1,0 3,9 2,8 0,0 CaO 6,5 6,3 6,2 6,2 6,5 0,0 0,0 SrO 0,9 0,9 0,9 0,9 0,0 0,0 0,0 BaO 0,0 0,0 0,0 0,0 0,0 0,0 3,5 LizO 0,0 0,0 0,0 0,0 0,0 0,0 0,0 Na2O 1,0 1,0 0,5 1,5 15,0 13,5 11,7 K2O 1,0 1,0 0,5 1,5 0,2 0,5 0,0 ZrO2 0,0 0,0 0,0 0,0 0,0 0,0 0,0 TiO2 0,0 0,0 8 6 0,0 0,0 0,9 CeO2 2 5 0,0 0,0 0,0 2,6 4,2 Fe2O3 0,005 0,005 0,005 0,005 0,0 0,0 0,0 SnO2 0,2 0,2 0,2 0,2 0,0 0,3 0,4 SO3 0,0 0,0 0,0 0,0 0,0 0,010 0,006 Cl 0,0 0,0 0,0 0,0 0,0 0,00 0,0 In total 99,9 99,9 100,0 100,0 100,0 100,0 100,0 Li2O + Na2O + K2O 2,0 2,0 1,0 3,0 15,2 14,0 11,7 CeO2 / Fe2O3 400 1000 0 0 - 660 - 5CeO2 + TiO2 10,0 25,0 8,0 6,0 0,0 12,8 21,9 Relative density ρ 2,42 2,48 2,43 2,43 2,50 2,47 2,57 Young's modulus E [GPa] 76,0 77,5 75,5 76,0 72,9 72,5 76,4 E / p [GPa] 31,3 31,2 31,1 31,3 29,2 29,4 29,7 CTE (50 °C to 200 °C) [ppm / K] 3,92 4,06 3,54 4,14 8,69 7,68 6,97 β-OH [mm -1 ] - - - - - 0,15 0,19 Average extinction change magnitude in a wavelength range from 400 nm to 800 nm during electron beam irradiation [based on a thickness of 100 µm] 0,003 0,001 - - 0,059 - - K IC [MPa m 1 / 2 ] 0,84 0,85 0,86 0,85 0,73 0,76 0,77 Transmittance at 100 µm at a wavelength of 400 nm 87 87 90 90 92 91 87 Transmittance at 100 µm at a wavelength of 300 nm 1 0 0 0 90 0 0 Transmittance at 100 µm ([at a wavelength of 400] - [at a wavelength of 300 nm]) 86 87 90 90 2 91 87 Wavelength [nm] at which a transmittance of 50% is achieved at a thickness of 100 µm - - - - - 343 353 Transmittance at 50 µm [at a wavelength of 400 nm] 89 89 91 91 91 - - Transmittance at 50 µm [at a wavelength of 300 nm] 10 1 1 4 90 - - Transmittance at 50 µm ([at a wavelength of 400] - [at a wavelength of 300 nm] 79 88 89 87 1 - - Wavelength [nm] at which a transmittance of 50% is present at a thickness of 50 µm 324 331 322 319 < 200 - - Absolute value of the distortion extent δ / length in the distortion direction of the glass (length in the distortion direction: 1000 mm, thickness: 0.1 mm) 0,11 0,14 0,05 0,1,5 0,89 0,72 0,62 Absolute value of the distortion δ / length in the distortion direction of the glass (length in the distortion direction: 1000 mm, thickness: 0.05 mm) 0,09 0,11 0,04 0,12 0,69 0,56 0,48 Absolute value of the degree of distortion δ / length in the distortion direction of the glass (length in the distortion direction: 500 mm, thickness: 0.1 mm) 0,06 0,07 0,03 0,07 0,45 0,36 0,31 Absolute value of the distortion extent δ / length in the distortion direction of the glass (length in the distortion direction: 500 mm, thickness: 0.05 mm) 0,04 0,05 0,02 0,06 0,34 0,28 0,24

[0122] As shown in Tables 1 to 6, in Examples 1 to 39, the relative density and the Young's modulus are approximately identical to those in Examples 40 to 42, which serve as comparative examples. Furthermore, the average extinction change in the wavelength range from 400 nm to 800 nm during electron beam irradiation is lower, and the value of (absolute value of the distortion δ / length in the distortion direction of the glass) is smaller than those in Examples 40 to 42. From this result, it is found that, according to the glass of the present embodiment, even when the glass is used for a solar cell in cases where the size is increased and the thickness is reduced, distortion of the solar cell can be effectively prevented.

[0123] As described above, the following items are described in this description. 1. Glass with a relative density of 2.2 to 2.7, exhibits a Young's modulus of 60 GPa or more, an average coefficient of thermal expansion in a range of 50 °C to 200 °C of 2.0 to 6.0 (× 10 -6 / K) exhibits has a rectangular shape, a main surface with one side measuring 50 cm or more and 300 cm or less, has a thickness of 0.01 mm or more and 0.5 mm or less, exhibits a total content of Li2O, Na2O and K2O of 0% to 3.5% as mass % based on oxides, and Contains 0.1% to 10% CeO2 as mass-% based on oxides. 2. Glass according to the preceding 1, further comprising, as mass % based on oxides: 0.01 % to 10 % TiO2. 3. Glass according to the preceding 1 or 2, further containing, as mass % based on oxides: 5% to 10% TiO2. 4. Glass having a relative density of 2.2 to 2.7, exhibits a Young's modulus of 60 GPa or more, an average coefficient of thermal expansion in a range of 50 °C to 200 °C of 2.0 to 6.0 (× 10 -6 / K) exhibits has a rectangular shape, a main surface with one side measuring 50 cm or more and 300 cm or less, has a thickness of 0.01 mm or more and 0.5 mm or less, and Contains 5% to 10% TiO2 as mass-% based on oxides. 5. Glass, containing as mass % based on oxides: 50% to 80% SiO2; 0% to 25% B2O3; 0% to 30% Al2O3; and 0.1% to 10% CeO2, and that has a total content of Li2O, Na2O and K2O of 0% to 3.5%, has a rectangular shape, a main surface with one side measuring 50 cm or more and 300 cm or less, and has a thickness of 0.01 mm or more and 0.5 mm or less. 6. Glass, containing as mass % based on oxides: 50% to 80% SiO2; 0% to 25% B2O3; 0% to 30% Al2O3; and 5% to 10% TiO2, and that has a total content of Li2O, Na2O and K2O of 0% to 3.5%, has a rectangular shape, a main surface with one side measuring 50 cm or more and 300 cm or less, and has a thickness of 0.01 mm or more and 0.5 mm or less. 7. Glass, containing as mass % based on oxides: 50% to 80% SiO2; 0% to 25% B2O3; 0% to 30% Al2O3 0.01% to 10% TiO2; and 0.1% to 10% CeO2, and that has a total content of Li2O, Na2O and K2O of 0% to 3.5%, has a rectangular shape, a main surface with one side measuring 50 cm or more and 300 cm or less, and has a thickness of 0.01 mm or more and 0.5 mm or less. 8. Glass according to any of the preceding 5 to 7, having an average coefficient of thermal expansion in a range of 50 °C to 200 °C of 2.0 to 6.0 (× 10 -6 / K). 9. Glass according to any of the preceding 1 to 8, having a total content of As2O3 and Sb2O3 of 0% or more and less than 0.25% as mass % on the basis of oxides. 10. Glass according to any of the preceding 1 to 9, further containing, as mass % based on oxides: 0.01 % to 0.4 % or less SnO2. 11. Glass according to any of the preceding 1 to 10, having a BaO content of 0% or more and 6.5% or less as mass % based on oxides. 12. Glass according to any of the preceding 1 to 11, which exhibits an average extinction change magnitude in a wavelength range of 400 nm to 800 nm during electron beam irradiation of 0.01 or less based on a thickness of 100 µm. 13. Glass according to any of the preceding 1 to 12, which has a fracture toughness value (K IC ) of 0.78 MPa · m 1 / 2 or more. 14. Glass according to any of the preceding 1 to 13, which has a value of 50% or more obtained by subtracting a light transmittance at a wavelength of 300 nm from a light transmittance at a wavelength of 400 nm. 15. Glass according to any of the preceding 1 to 14, which has a value E / p, obtained by dividing a Young's modulus E (GPa) by a relative density p, of 27.0 GPa or more. 16. Glass according to one of the preceding 1 to 15, which has a β-OH of 1.0 mm -1 or less. 17. Glass according to any of the preceding 1 to 16, comprising: a conductive film on at least one surface. 18. Glass according to any of the preceding 1 to 17, comprising: an anti-reflective film on at least one surface. 19. Solar cell cover glass for a space satellite, comprising: the glass according to any of the preceding 1 to 18. 20. UV-blocking glass, comprising: the glass according to any of the preceding 1 to 18. 21. Electron beam shielding glass, comprising: the glass according to any of the preceding 1 to 18.

[0124] It should be noted that the present application is based on Japanese patent application No. 2023-152237, which was filed on September 20, 2023, and the contents of which are incorporated herein by reference. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP S63-95138 A

[0003] WO 2023 / 022074

[0003] JP 2023-152237

[0124] Cited non-patent literature

[0000] Acta metall. mater., Volume 43, Pages 3453-3458, 1995

[0113] < / anwendung> < / zusammensetzung> < / glas>

Claims

[1] Glass having a relative density of 2.2 to 2.7, exhibits a Young's modulus of 60 GPa or more, an average coefficient of thermal expansion in a range of 50 °C to 200 °C of 2.0 to 6.0 (× 10 -6 / K) exhibits has a rectangular shape, a main surface with one side measuring 50 cm or more and 300 cm or less, has a thickness of 0.01 mm or more and 0.5 mm or less, exhibits a total content of Li2O, Na2O and K2O of 0% to 3.5% as mass % based on oxides, and comprises 0.1% to 10% CeO2 as mass % based on oxides. [2] Glass according to claim 1, further comprising, as mass % based on oxides: 0.01 % to 10 % TiO2. [3] Glass according to claim 1, further comprising, as mass % based on oxides: 5% to 10% TiO2. [4] Glass having a relative density of 2.2 to 2.7, exhibits a Young's modulus of 60 GPa or more, an average coefficient of thermal expansion in a range of 50 °C to 200 °C of 2.0 to 6.0 (× 10 -6 / K) exhibits has a rectangular shape, a main surface with one side measuring 50 cm or more and 300 cm or less, has a thickness of 0.01 mm or more and 0.5 mm or less, and comprises 5% to 10% TiO2 as mass-% based on oxides. [5] Glass, comprising mass % based on oxides: 50% to 80% SiO2; 0% to 25% B2O3; 0% to 30% Al2O3; and 0.1% to 10% CeO2, and that has a total content of Li2O, Na2O and K2O of 0% to 3.5%, has a rectangular shape, a main surface with one side measuring 50 cm or more and 300 cm or less, and has a thickness of 0.01 mm or more and 0.5 mm or less. [6] Glass, comprising mass percent based on oxides: 50% to 80% SiO2; 0% to 25% B2O3; 0% to 30% Al2O3; and 5% to 10% TiO2, and that has a total content of Li2O, Na2O and K2O of 0% to 3.5%, has a rectangular shape, a main surface with one side measuring 50 cm or more and 300 cm or less, and has a thickness of 0.01 mm or more and 0.5 mm or less. [7] Glass, comprising mass percent based on oxides: 50% to 80% SiO2; 0% to 25% B2O3; 0% to 30% Al2O3 0.01% to 10% TiO2; and 0.1% to 10% CeO2, and that has a total content of Li2O, Na2O and K2O of 0% to 3.5%, has a rectangular shape, a main surface with one side measuring 50 cm or more and 300 cm or less, and has a thickness of 0.01 mm or more and 0.5 mm or less. [8] Glass according to any one of claims 5 to 7, having an average coefficient of thermal expansion in a range from 50 °C to 200 °C of 2.0 to 6.0 (× 10 -6 / K). [9] Glass according to any one of claims 1 to 7, having a total content of As2O3 and Sb2O3 of 0% or more and less than 0.25% as mass % based on oxides. [10] Glass according to any one of claims 1 to 7, further comprising, as mass % based on oxides: 0.01% to 0.4% or less SnO2. [11] Glass according to any one of claims 1 to 7, having a BaO content of 0% or more and 6.5% or less as mass % based on oxides. [12] Glass according to any one of claims 1 to 7, which has an average extinction change magnitude in a wavelength range of 400 nm to 800 nm during electron beam irradiation of 0.01 or less based on a thickness of 100 µm. [13] Glass according to any one of claims 1 to 7 having a fracture toughness value (K IC ) of 0.78 MPa · m 1 / 2 or more. [14] Glass according to any one of claims 1 to 7, having a value of 50% or more obtained by subtracting a light transmittance at a wavelength of 300 nm from a light transmittance at a wavelength of 400 nm. [15] Glass according to any one of claims 1 to 7, having a value E / p obtained by dividing a Young's modulus E (GPa) by a relative density ρ of 27.0 GPa or more. [16] Glass according to any one of claims 1 to 7, comprising a β-OH of 1.0 mm -1 or less. [17] Glass according to any one of claims 1 to 7, comprising: a conductive film on at least one surface. [18] Glass according to any one of claims 1 to 7, comprising: an anti-reflective film on at least one surface. [19] Solar cell cover glass for a space satellite, comprising: the glass according to any one of claims 1 to 7. [20] UV-blocking glass, comprising: the glass according to any one of claims 1 to 7. [21] Electron beam shielding glass comprising: the glass according to any one of claims 1 to 7.

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