DIAPHRAGM

PROBLEM TO BE SOLVED: To provide a diaphragm capable of reducing deterioration caused by stress concentration at a thin film part, and improving durability of a diaphragm. SOLUTION: The thin film part 3 is integrally formed with an outer circumference at a lower end of a valve element part 2 formed in a columnar form, and a thick circumferential edge part 4 is integrally formed with the outer circumference of the thin film part 3. The thin film part 3 is extended horizontally from the outer circumference at the lower end of the valve element part 2. A first part 3a protruded in an upward semi-circular form is connected to a second part 3b protruded in a downward semi-circular form through a third part 3b to make a gentle S-form. In accordance with valve opening/closing action of the valve element part 2, the first part 3a and the second part 3b are freely deformed, so that stress is dispersed to each part of the thin film part 3. COPYRIGHT: (C)2004,JPO