The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 21, 2010
Filed:
Dec. 17, 2004
Makoto Watanabe, Saitama, JP;
Mizuki Mori, Saitama, JP;
Makoto Watanabe, Saitama, JP;
Mizuki Mori, Saitama, JP;
Citizen Holdings Co., Ltd., Tokyo, JP;
Abstract
A directional speaker that vibrates a diaphragm to send sound waves includes reproducing signal generation meansfor outputting a reproducing audible signal; ultrasonic signal generation meansfor outputting a carrier wave signal at a frequency in an ultrasonic band; phase modulation meansfor phase modulating the carrier wave signal with the reproducing audible signal to output a modulated carrier wave signal; and diaphragm driving meansfor vibrating the diaphragm based on a compression cycle of the modulated carrier wave signal. The configuration, in which the ultrasonic carrier wave is modulated with an audio signal, can generate a small, narrow-directional audible sound field without using a parametric effect. At the same time, the ultrasonic carrier wave is modulated in such a way that the sound pressure distribution of a target audio signal (reproducing audible signal) can be obtained for output and, therefore, the sound quality of a sound signal output from the directional speaker is improved.