Patent ID: 7226881

Claim:
Glass-ceramics having an average liner thermal expansion coefficient within a range of 0.0±0.2×10 −7 /° C. within a temperature range from 0° C. to 50° C., having difference between the maximum value and the minimum value of ΔL/L of 10×10 −7 or below, and comprising SiO 2 , Al 2 O 3 , and P 2 O 5 with the total amount thereof in mass % being within a range from 86.7% to 89.0% and further comprising CaO in an amount of 0.5 mass % or more, wherein the ratio of P 2 O 5 to Al 2 O 3 in mass % is within a range from 0.270 to 0.33 and the ratio of P 2 O 5 to SiO 2 in mass % is within a range from 0.1230 to 0.1450.