Patent ID: 6931142

Claim:
An insert earphone adapted to be inserted into an external auditory meatus comprising: a receiver unit having a sound passage tube; an ear chip attached to the receiver unit and comprising a barrel portion for defining a sound passage communicating to a sound passage of the sound passage tube of the receiver unit, a first annular flange portion having the shape of a parabola spreading from the top end of the barrel portion toward the middle thereof, the first annular flange portion forming a top end of the ear chip, and a second annular flange portion having the shape of a parabola spreading from the middle of the barrel portion toward a base end thereof; and the first annular flange portion having a smaller outer diameter compared with the second annular flange portion, wherein the first annular flange portion has almost even thickness from the inner circumference thereof to the outer circumference thereof, and the first annular flange portion has an inner circumference neighborhood substantially formed in the shape of a sliced doughnut, a top end face of the barrel portion is positioned closer to the base end side than is the inner circumference neighborhood, and the inner circumference neighborhood has a smooth circular arc portion.