초록 ▼

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

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.

대표청구항 ▼

[ What is claimed is:] [1.]1. An actuator comprising:a) a support beam;b) a first means for placing said support beam in compression without causing flexure of said support beam;c) a first layer of material adhered to a first surface of said support beam; andd) a second means for causing movement of

[ What is claimed is:] [1.]1. An actuator comprising:a) a support beam;b) a first means for placing said support beam in compression without causing flexure of said support beam;c) a first layer of material adhered to a first surface of said support beam; andd) a second means for causing movement of said first layer of material to cause a flexure of said layer of material and said support beam.