| 摘要 |
PROBLEM TO BE SOLVED: To improve economical efficiency and mass productivity, and cope with the requirement of high accuracy by adjusting a degree of orientation of a crystal face by controlling elements being contained in a metallic material and degrading an etching characteristic, and imparting mechanical characteristics not less than a fixed level. SOLUTION: To set a thermal expansion coefficient in the same degree as a thermal expansion coefficient (6 to 10×10<-6> / deg.C) of front glass, wt.% of Ni is regulated to 43 to 56. An element C influencing an etching speed is set not more than 0.015% in terms of a cost through a speed increases as it becomes less. Since elements Mn, Si used as a deoxidizer deteriorate etching performance when they are much, Mn is set not more than 0.60%, and Si is set not more than 0.20%. Elements P, S hindering hot workability are set not more than 0.004%, and an element B improving hot workability is controlled in 0.003% or less to avoid reduction in an etching speed. Inclusion forming elements O, N are set not more than 0.004% since they exert adverse influence on an etching hole shape. |
