Ultrasonic driving element
AssigneeRobert Bosch GmbH
InventorsGert Lindemann, Klaus-Peter Schmoll, Gerhard Keuper, Jorg Wallaschek
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Abstract
An an ultrasonic drive element having a plurality of layers of piezoelectric material, arranged one on top of another to form a stack, between each of which is located a contacting layer for application of an operating voltage. Each of the contacting layers is subdivided into at least two electrically unconnected subregions, at least one of which has an electrode for making contact to the adjacent piezoelectric layers. By applying suitable alternating-current voltages to the electrode, the surface of the layer stack is excited into mechanical oscillations which contain a motion component parallel to the plane of said surface.
Claims16
An ultrasonic drive element comprising:
- a plurality of piezoelectric layers, a first piezoelectric layer of the plurality of piezoelectric layers arranged on top of a second piezoelectric layer of the plurality of piezoelectric layers to form a layer stack;
- and
- a contacting layer including at least two subregions and being positioned between the first piezoelectric layer and the second piezoelectric layer, each subregion including at least one electrode, the electrode contacting the first and second piezoelectric layers and receiving a respective operating alternating-current voltage that excites a surface of the layer stack to generate mechanical oscillations, each of the mechanical oscillations having a respective motion component parallel to a plane of the surface of the layer stack,
- wherein the respective alternating-current voltage includes a first voltage for exciting the layer stack to generate longitudinal oscillations, the first voltage being applied to at least a first portion of the at least one electrode,
- wherein the respective alternating-current voltage includes a second voltage, wherein the second voltage is shifted 90 degrees with respect to the first voltage,
- wherein the plurality of piezoelectric layers are arranged in turret-like stacks, a first stack of the turret-like stacks being crenellate-positioned next to a second stack of the turret-like stacks on at least one common piezoelectric base layer and being activated so that the first stack is polarized in a same direction as the second stack.
An ultrasonic drive element comprising:
- a plurality of piezoelectric layers, a first piezoelectric layer of the plurality of piezoelectric layers situated on top of a second piezoelectric layer of the plurality of piezoelectric layers to form a layer stack;
- and
- a contacting layer including at least two subregions and being situated between the first piezoelectric layer and the second piezoelectric layer, each of the subregions including at least one electrode, the at least one electrode contacting the first and second piezoelectric layers and receiving a respective operating alternating-current voltage that excites a surface of the layer stack to generate mechanical oscillations,
- wherein the respective alternating-current voltage includes a first voltage for exciting the layer stack to generate longitudinal oscillations, the first voltage being applied to at least a first portion of the at least one electrode,
- wherein the respective alternating-current voltage includes a second voltage, and
- wherein the plurality of piezoelectric layers are situated in turret-like stacks, a first stack of the turret-like stacks being crenellate-positioned next to a second stack of the turret-like stacks on at least one common piezoelectric base layer and being activated so that a polarization of the first stack is tuned to a polarization of the second stack.
Dependencies are inferred from the claim text.