Encapsulated thermoacoustic projector based on freestanding carbon nanotube film
US9635468B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 2014 |
| Grant date | Apr 25, 2017 |
| Priority date | — |
| Expiry date | Mar 29, 2034 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S977/932
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A suspended nanotube film (or films) producing sound by means of the thermoacoustic (TA) effect is encapsulated between two plates, at least one of which vibrates, to enhance sound generation efficiency and protect the film. To avoid the oxidation of carbon nanotubes at elevated temperatures and reduce the thermal inertia of surrounding medium the enclosure is filled with inert gas (preferably with high heat capacity ratio, γ=Cp/Cv, and low heat capacity, Cp). To generate sound directly as the first harmonic of applied audio signal without use of an energy consuming dc biasing, an audio signal modulated carrier frequency at much higher frequency is used to provide power input. Various other inventive means are described to provide enhanced projected sound intensity, increased projector efficiency, and lengthened projector life, like the use of infrared reflecting coatings and particles on the projector plates, non-parallel sheet alignment in sheet stacks, and cooling means on one projector side.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.