US Patent 7714701 Active material based haptic alert system

A haptic alert system generally includes an active material based actuator for providing the haptic alert. The active material based actuators refer to the use of several different classes of active materials all of which exhibit a change in at least one attribute such as dimension, shape, and/or flexural modulus when subjected to at least one of many different types of applied activation signals, examples of such signals being thermal, electrical, magnetic, stress, and the like.