Patent ID: 9374644
Filing Date: 2016-06-21
CPC Classification: H04R

Claim Text:
1. An acoustic transducer comprising: a vibrating film and a fixed film formed above an opening portion of a substrate; and at least a first sensing portion and a second sensing portion that detect sound waves using change in capacitance between a vibrating electrode provided in the vibrating film and a fixed electrode provided in the fixed film, convert the sound waves into electrical signals, and output the electrical signals, wherein, in the first sensing portion and the second sensing portion, the fixed film is used in common, and the vibrating electrode is divided into a first sensing region and a second sensing region that respectively correspond to the first sensing portion and the second sensing portion, wherein, in the first sensing portion, a protrusion portion that protrudes toward the vibrating electrode is provided on a region of the fixed film that opposes the first sensing region, wherein, when voltage is applied between the fixed electrode and the vibrating electrode, the vibrating film comes into contact with the protrusion portion such that the first sensing region of the vibrating electrode is relatively fixed to the fixed film in a state in which an air gap that is a first predetermined gap is formed between the fixed electrode and the vibrating electrode, and when the voltage application is canceled, the relative fixed state of the first sensing region is also canceled, wherein, in the second sensing portion, the vibrating film in the second sensing region is fixed to the substrate or the fixed film in a state in which an air gap that is a second predetermined gap is formed between the fixed electrode and the vibrating electrode, and wherein in the second sensing portion, regardless of voltage application between the fixed electrode and the vibrating electrode, the vibrating film in the second sensing region is fixed in a state of being constantly joined to the substrate or the fixed film in a state in which the air gap that is the second predetermined gap is formed.