Inertial/audio unit and construction

The present invention relates generally to sound generating signal units such as loud speakers and tone generators, and also relates to buzzers, vibrators and devices used for generating a vibration or inertial signal which may be felt or sensed while not producing a highly audible sound. Assemblies of this latter type in the prior art are used, for example, to signal a query by or an active state of a beeper, pager or alarm system, or to otherwise indicate an attention-getting state of a consumer device. An electrically driven signal unit is adapted for one-step assembly or injection molding with a device housing to vibrate, flex, beep or emit audio signals, or to sense and provide tactile feedback or control. The signal unit is a package with one or more active areas each containing a layer of ferroelectric or piezoelectric material, connected by inactive areas which may position, align and conduct electricity to the active areas. The active areas may be coupled over a region to transmit compressional, shear or flexural wave energy into the housing, or may contact at discrete regions while bending or displacing elsewhere to create inertial disturbances or impulses which are coupled to create a tactile vibration of the housing. The unit may be assembled such that the housing, the sheet or discrete areas thereof form a bender to provide tactile or sub-auditory signals to the user, or may be dimensioned, attached and actuated to produce audio vibration in the combined structure and constitute a speaker. In other embodiments one or more active regions of piezo material are attached to thin or movable wall regions of the unit to sense strain and, in conjunction with a conditioning circuit, produce electrical switching or control signals for the device. The invention also includes electroactive sheet structures having a polymer block, bracket or functional body formed therearound, which serves as a mounting, coupling or functional operating structure for the driven device.