JOURNALS

摘要

NHK has been developing a flexible sheet-type display for 8K Super Hi-Vision (SHV). The audio system for 8K SHV is a 22.2 multichannel sound system employing multiple audio channels on the display, therefore a loudspeaker capable of directly emitting sound from the surface of the display is strongly required. Thus, a thermoacoustic transducer has been studied as a promising solution to this problem. The thermoacoustic transducer used in this study is composed of an aluminum electrode, a polyimide film, and a graphite sheet in order for it to be thin and bendable. A theoretical model was developed to calculate the radiated sound pressure on the basis of a fundamental equation for the heat transfer between the transducer and surrounding air. A square root circuit was designed to suppress the second harmonic distortion intrinsic to the thermoacoustic transducer and the effectiveness of the circuit was experimentally confirmed.