ELECTROSTATIC ULTRASONIC TRANSDUCER, ULTRASONIC SPEAKER, METHOD, DEVICE AND PROGRAM FOR DESIGNING TRANSDUCER, METHOD FOR REPRODUCING SOUND SIGNAL, METHOD FOR MANUFACTURING, SUPER-DIRECTIVITY SOUND SYSTEM AND DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a push/pull type electrostatic ultrasonic transducer where low voltage (low power) operation is obtained by obtaining a height of projecting parts of fixed electrodes quantitatively so as to generate the same sound pressure with smaller energy, an ultrasonic speaker using the transducer, a method, a device and a program for designing the transducer, a method for reproducing a sound signal, method for manufacturing, a super-directivity sound system, and a projector.;SOLUTION: In the push/pull type electrostatic ultrasonic transducer 1, a formula for optimally setting the height (t) of the projecting parts of the fixed electrodes 10A and 10B when a desired sound pressure and a driving frequency are given is formalized. The formula is obtained by a=(1/πf)√{(I_O×10^P/10)/2ρ_Oc} when it is assumed that the desired sound pressure is P(dB), the driving frequency is f(Hz) and a value of one side amplitude of a film oscillation 12 is a(m). Wherein, Io denotes the reference acoustic intensity being 0.96×10^-12(W/m²), ρo is the density of the air being 1.2(kg/m³) and (c) denotes the sound speed in the air being around 340(m/S). A value exceeding and closest to the one side amplitude value "a" obtained by the formula (at least in a range where an oscillation film never contacts with an electrode due to the film oscillation) is set to be the height (t) of the projecting parts of the fixed electrodes.;COPYRIGHT: (C)2007,JPO&INPIT