| 摘要 |
PROBLEM TO BE SOLVED: To integrate a fixed polar plate and a pedestal without varying a mechanical coupling force when shortening a distance between acoustic terminals by reducing thickness of the pedestal included within a unit.SOLUTION: In a capacitor microphone unit including a diaphragm 20 and a fixed polar plate 40, a pedestal 50 is provided which is formed from a disc body supporting the fixed polar plate 40. The pedestal 50 includes: a recess 51 which forms an air chamber of predetermined capacity between the pedestal 50 and the fixed polar plate 40 while leaving a peripheral portion; a rib wall 52 which includes a first support surface 52a opposite to an edge of the fixed polar plate 40 and is formed annular along the peripheral portion of the pedestal 50; and a protrusion 53 which includes a second support surface 53a opposite to a substantial center portion of the fixed polar plate 40 and is protrusively provided within the recess 51. Surface grinding is applied to the first support surface 52a of the rib wall 52 and the second support surface 53a of the protrusion 53 by a grindstone, the support surfaces 52a and 53a are finished on the same plane, and the fixed polar plate 40 is fixed to the support surfaces 52a and 53a by an adhesive material. |
