Patent ID: 6477257
Filing Date: 2002-11-05
Classification: H04R

Abstract:
A directional microphone comprising:a yoke having a surrounding wall portion with front and rear ends, and an end wall portion disposed to close said rear end of said surrounding wall portion; a magnet disposed in said yoke, said magnet having a front side and a rear side that lies against said end wall portion of said yoke; a washer disposed in said yoke, said washer having a front side and a rear side that lies against said front side of said magnet; an annular cap body enclosing said surrounding wall portion of said yoke and having a front portion with a front end face, a rear portion with a rear end face, a plurality of first air passages that extend from said front end face through said rear end face and that are angularly spaced apart from each other, and a plurality of second air passages formed in said front portion, each of which has a radial first section that extends in a radial inward direction from an outer wall surface of said front portion, and an axial second section that extends from an innermost end of said first section to said front end face; a voice coil disposed around said washer and said magnet within said surrounding wall portion of said yoke; a diaphragm disposed adjacent to said front end face of said cap body and having a peripheral portion connected to said voice coil; a protective cover including a perforated cover plate, and an annular surrounding wall that extends from a periphery of said cover plate and that is coupled to said front portion of said cap body without covering said first sections of said second air passages and with said cover plate disposed proximate to said diaphragm; and an air chamber unit coupled to said rear portion of said cap body and in communication with said first air passages; said rear portion of said cap body having an outer wall surface formed with a guide groove unit and a plurality of recesses for inter-communicating said first sections of said second air passages and said guide groove unit.