Patent ID: 7221875

Claim:
An optical-acoustic transducer comprising a diaphragm with a support portion of a vibrating section being connected to the vibrating section vibrated with sound, with the suitable number of cantilevers, and a light emitter and a light receiver placed to oppose to a light reflecting portion formed at the vibrating section of the diaphragm, and detecting a change in a position of the vibrating section following the vibration of said vibrating section by receiving light, irradiated from said light emitter and reflected at the light reflecting portion of said vibrating section, at said light receiving element, wherein said cantilevers are formed by performing slit working for said diaphragm, and a portion between an outer circumference edge of said vibrating section and inner circumference edges of said cantilevers and a portion between an inner circumference edge of said support portion and outer circumference edges of said cantilevers are partitioned by said slit working, and said cantilevers extend along a portion between an outer circumference of said vibrating section and an inner circumference of said support portion, wherein a rising portion rising vertically or diagonally upward from an outer circumference edge of the light reflecting portion forming said vibrating section is provided along an entire circumference, a falling portion falling downward in an arc form from an upper end circumference edge of said rising portion is provided along an entire circumference, a flat portion extending horizontally to an outside from a lower end circumference edge of said failing portion is provided at an entire circumference, and the cantilevers extending alone the outer circumference of said vibrating section are formed at the flat portion, thereby to enhance the rigidity of the vibrating section so as to improve the optical-acoustic transducing characteristic.