| 摘要 |
A small photodetector type microphone (10) exhibiting excellent directivity without requiring any mirror surface. A diaphragm (27) vibrates in response to a sound pressure. An optical waveguide (28) is formed along the diameter of the diaphragm (27) and integral vibration of the optical waveguide (28) and the diaphragm (27) causes a variation in the quantity of light leaking from the optical waveguide (28) to the outside thus causing a variation in the quantity of light being transmitted across the optical waveguide (28). The optical waveguide (28) has one end side for introducing light into a light emitting elements (20) and the other end side for delivering light to a light receiving element (24). The light receiving element (24) outputs an electric signal related to the quantity of incident light. <IMAGE> |
