| 摘要 |
The present invention relates to a receiver unit (A) having a receiver body (1), and more particularly to a receiver unit (A) having a receiver body (1) in which a countermeasure for flattening the sound pressure characteristic is taken on the receiver unit itself. According to the invention, the sound pressure characteristic of the receiver unit (A) can be flattened, and a handset to which the receiver unit (A) is attached can be miniaturized. The sound pressure characteristic of the receiver body (1) is flattened by adding a cavity (22, 26) to a front or back portion, or both front and back portions of the receiver body (1). Preferably, the cavity (22, 26) has a Helmholtz resonant structure (6, 7). The cavity (22) has a leakage path (23) which acoustically communicates with the external space. The cavity (22) is formed by the internal space of a case (2) which houses the receiver body (1). A through hole (24) constituting a leakage path (23) is disposed in a wall of the case. The internal space (53) of a handset (5) of a mobile information terminal device is used as the external space. An attachment piece (25) may be disposed on the case (2). The case (2) may be housed in an electrically insulating holder.
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