1. Field of the Invention
The present invention relates to a microphone unit that converts a sound pressure (generated such as by voice) into electrical signals and outputs the resulting signals.
2. Description of Related Art
Conventionally, microphone units are applied to voice input devices, examples of which are sound communication devices such as mobile telephones and transceivers, information processing systems, such as voice authentication systems, that utilize a technology for analyzing input voice and recording devices. Conventionally, as these microphone units, microphone units having various configurations are developed (for example, see patent document 1).
FIG. 6 is a schematic cross-sectional view showing an example of the configuration of a conventional microphone unit. Among conventional microphone units, there is a microphone unit that includes, as with the microphone unit 100 shown in FIG. 6, a board 101 that has an opening portion 101a which is used as a sound passage, a MEMS (micro electro mechanical system) chip 102 that is mounted on the board 101 so as to cover the opening portion 101a, an IC (integrated circuit) 103 that is mounted on the board 101 and is connected electrically through a wire 105 to the MEMS chip 102, and a shield cover 104 that covers the MEMS chip 102 and the IC 103 mounted on the board 101.
The microphone unit 100 configured as described above converts, with the MEMS chip 102, sound signals transmitted through the opening portion 101a into electrical signals, amplifies the resulting electrical signals with the IC 103 and outputs the amplified signals through an unillustrated electrical pad to the outside.
Patent document 1: JP-A-2008-92183