| 摘要 |
PURPOSE:To improve reliability against external force without causing a defect, breakdown, etc., due to the action of exteral mechanic force by forming a case of a transparent material with a concavity through corrosion work and by constituting a crystal vibrator using this case. CONSTITUTION:On each side of transparent material 7 of thickness (t4) as a case raw material of crystal or glass, metal film 8 and protective film 9 of photo resist on it are both stacked. This transparent material 7 is corrosion-worked to form external circumferential part 7b of the case. Then, corroding metal film 8 exposes the surface of the transparent material where a concavity is formed. Next, corroding transparent material 7 forms concavity 7a of concavity corrosion work depth (t5) at the its minimum of a need. Concavity 7a is removed through corrosion to form case surface 7c. Consequently, its reliability against external force can be improved. |
