US 6,545,384 · Granted 2003-04-08

The Stretchy Polymer That Turns Electricity Into Motion

Imagine a plastic-like material that moves when you zap it with electricity, and generates electricity when you stretch it. That's an electroactive polymer—a smart material that converts between electrical and mechanical energy. This patent covers how to make these materials work better by pre-stretching them before use, kind of like pre-tensioning a spring.

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The plain-English version

What it protects

The claim covers transducers made from pre-strained electroactive polymers that convert electrical energy into mechanical motion (and vice versa), along with the compliant electrodes that shape-shift to fit the polymer's surface. What's protected here is the specific approach of pre-straining the polymer before assembly to boost its energy conversion efficiency, plus the manufacturing methods for building these electromechanical devices.

Why it matters

Electroactive polymers are fundamental to next-generation actuators and sensors used in robotics, soft robotics, haptic feedback devices, and adaptive structures. By improving the conversion efficiency through pre-strain, this patent addresses a core technical hurdle in making these materials practical for real products. The patent's coverage of compliant electrodes and fabrication methods protects a platform approach that competitors would need to license or design around.

Real-world use

You encounter this technology in haptic feedback devices like game controllers that vibrate, flexible robotic grippers, and next-generation speaker cones that can move in multiple directions.

Original USPTO abstract

The present invention relates to transducers, their use and fabrication. The transducers convert between mechanical and electrical energy. Some transducers of the present invention include a pre-strained polymer. The pre-strain improves the conversion between electrical and mechanical energy. The present invention also relates to devices including an electroactive polymer to convert between electrical and mechanical energy. The present invention further relates to compliant electrodes that conform to the shape of a polymer included in a transducer. The present invention provides methods for fabricating electromechanical devices including one or more electroactive polymers.

Patent details

Publication number: US 6,545,384
Filing date: 2000-07-20
Grant date: 2003-04-08
Assignee: Sri International
Inventor(s): PELRINE RONALD E., KORNBLUH ROY D.
CPC class: H04R19/02

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