Transfer having a coupling coefficient higher than its active material
US6236143A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 25, 1999 |
| Grant date | May 22, 2001 |
| Priority date | — |
| Expiry date | Aug 25, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10N30/2041
Abstract
A coupling coefficient is a measure of the effectiveness with which a shape-changing material (or a device employing such a material) converts the energy in an imposed signal to useful mechanical energy. Device coupling coefficients are properties of the device and, although related to the material coupling coefficients, are generally different from them. This invention describes a class of devices wherein the apparent coupling coefficient can, in principle, approach 1.0, corresponding to perfect electromechanical energy conversion. The key feature of this class of devices is the use of destabilizing mechanical pre-loads to counter inherent stiffness. The approach is illustrated for piezoelectric and thermoelectrically actuated devices. The invention provides a way to simultaneously increase both displacement and force, distinguishing it from alternatives such as motion amplification, and allows transducer designers to achieve substantial performance gains for actuator and sensor devices.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.