Piezo haptic feedback device with integrated support
According to an embodiment, a device comprises: a piezoelectric element configured to convert an electrical voltage into a mechanical strain; and a conductive base plate onto which the piezoelectric element is fastened, wherein the conductive base plate comprises an integrated support positioned on an underside of the conductive base plate, wherein the conductive base plate is supported by the integrated support; wherein the device is configured to provide haptic feedback on a basis of the mechanical strain.
1. A device, comprising:
a piezoelectric element configured to convert an electrical voltage into a mechanical strain, wherein an electrode is fastened to a top surface of the piezoelectric element;
a conductive base plate onto which the piezoelectric element is fastened, wherein the conductive base plate is configured as a lower electrode of the piezoelectric element,
wherein the conductive base plate comprises an integrated support positioned on an underside of the conductive base plate, wherein the integrated support is formed into the conductive base plate by punching or by bending edges of the conductive base plate; and
a carrier layer, wherein the conductive base plate lies on the carrier layer and the conductive base plate is supported by the integrated support;
wherein the device is configured to provide haptic feedback on a basis of the mechanical strain.
2. The device of claim 1 , wherein the mechanical strain caused by the voltage bends the piezoelectric element and the conductive base plate.
3. The device of claim 1 , wherein the piezoelectric element comprises multiple piezoelectric layers configured electrically either in series or in parallel.
4. The device of claim 1 , wherein the piezoelectric element or the conductive base plate is a circular or an oval disk.
5. The device of claim 1 , wherein the piezoelectric element or the conductive base plate is a polygon shaped disk.
6. The device of claim 1 , wherein the integrated support is positioned on an outer circumference of the conductive base plate.
7. The device of claim 1 , wherein the piezoelectric element is configured to convert mechanical strain into electrical voltage to detect touch.
8. The device of claim 1 , wherein the piezoelectric element and the conductive base plate are electrically connected to a conductive film.
9. The device of claim 1 , wherein height of the integrated support is configured to allow 10-200 micrometre, μm, pre-bending of the piezoelectric element, 10-200 μm haptic movement of the piezoelectric element, and 1-200 μm movement of the piezoelectric element due to touch.
10. The device of claim 1 , wherein height of the integrated support is configured so that maximum total bending of the piezoelectric element is limited to a chosen value in a range 200-500 μm.
11. The device of claim 1 , wherein the integrated support is configured on a same side than the piezoelectric element.
12. The device of claim 1 , wherein the integrated support is configured to be conductive.
13. The device of claim 1 , wherein the device further comprises a hermetically sealed cavity, and wherein the piezoelectric element and the conductive base plate are located in the hermetically sealed cavity.