Low expansion transparent glass ceramics
AssigneeKabushiki Kaisha Ohara
InventorsHiroyuki Minamikawa, Kazuo Ohara, Naoyuki Goto
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Abstract
There are provided low expansion transparent glass-ceramics obtained by heat treating a base glass produced at a relatively low melting temperature of 1530° C. or below. The glass-ceramics have an average linear thermal expansion coefficient within a range from +6×10−7/° C. to +35×10−7/° C., 80% transmittance wavelength (T80) of 700 nm or below internal transmittance of 75% or over at light wavelength of 1550 nm, heat resisting temperature of 800° C. or over and Young's modulus of 90 GPa or over. The glass-ceramics comprise SiO2, Al2O3, MgO, CaO, BaO, ZnO, Li2O, TiO2 and ZrO2 and contain β-quartz or β-quartz solid solution as a predominant crystal phase.
Claims23
Low expansion transparent glass-ceramics obtained by heat treating a base glass containing 3–15% ZnO in mass % based on the total amount of oxides present and which is produced at a melting temperature of 1530° C. or below, said glass-ceramics containing β-quartz or β-quartz solid solution as a predominant crystal phase and 50%–60% SiO2 in mass % on the basis of amount of total oxides, being free of K2O and Na2O, having an average linear thermal expansion coefficient (α) within a range from +6×10−7/° C. to +35×10−7/° C. within a temperature range from 100° C. to 300° C. and having 80% transmittance wavelength (T80) of 700nm or below.
Low expansion transparent glass-ceramics obtained by heat treating a base glass containing 3%–15% ZnO in mass % based on the total amount of oxides present and which is produced at a melting temperature of 1530° C. or below, said glass-ceramics containing 50%–60% SiO2 in mass % on the basis of amount of total oxides and 1.5%–3.5% Li2O on the basis of amount of total oxides, being free of K2O and Na2O, having an average linear thermal expansion coefficient (α) within a range from +6×10−7/° C. to +35×10−7/° C. within a temperature range from 100° C. to 300° C. and having 80% transmittance wavelength (T80) of 700 nm or below.
Dependencies are inferred from the claim text.