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:
Jun. 13, 2000
Filed:
Nov. 25, 1998
Munehiro Date, Minato-ku, Tokyo 108-0071, JP;
The Institute of Physical and Chemical Research, Saitama, JP;
Other;
Abstract
A variably sound-absorbing device comprises a piezoelectric material 32 the peripheral portion of which is fixed to a frame 31 or the like, at least one pair of electrodes 34 formed on opposite surfaces of the piezoelectric material, and at least one circuit element 36 through which the electrodes are connected to each other. The piezoelectric material 32 is boardlike and curved, and an electrical characteristic of the circuit element 36 (a circuit showing a negative capacitance for example) is variable. The modulus of elasticity (the real number part of the modulus of elasticity) and the loss factor (the imaginary number part of the modulus of elasticity) of the piezoelectric material are thereby varied and the sound-absorbing characteristic is electrically varied to a considerable extent.