Button device using piezoelectric element
A button device includes a piezoelectric element which includes a piezoelectric body with one surface on which a first external electrode and a second external electrode are formed and a plate with one surface attached to the other surface of the piezoelectric body, a supporting plate disposed on the one surface of the piezoelectric body, a cover disposed on the other surface of the plate, a first spacer provided between an edge portion of the one surface of the plate and the supporting plate, a second spacer provided between at least a part of an edge portion of the other surface of the plate and the cover to provide a separation space between the plate and the cover, and a dot provided in the separation space to transfer an external force to the piezoelectric element or to transfer a vibration of the piezoelectric element to the cover.
1. A button device using a piezoelectric element, comprising:
the piezoelectric element which comprises a piezoelectric body with one surface on which a first external electrode and a second external electrode are formed and a plate with one surface attached to the other surface of the piezoelectric body;
a supporting plate disposed on the one surface of the piezoelectric body;
a cover disposed on the other surface of the plate;
a first spacer provided between an edge portion of the one surface of the plate and the supporting plate to provide a space in which the piezoelectric element is deformable due to an external force applied to the cover;
a second spacer provided between at least a part of an edge portion of the other surface of the plate and the cover to provide a separation space between the plate and the cover; and
a dot provided in the separation space to transfer the external force to the piezoelectric element or to transfer a vibration of the piezoelectric element to the cover.
2. The button device of claim 1 , further comprising an adhesive between the plate and the second spacer and an adhesive between the second spacer and the cover.
3. The button device of claim 1 , wherein the second spacer is a double-sided adhesive tape.
4. The button device of claim 1 , wherein the separation space is empty.
5. The button device of claim 1 , wherein the separation space is filled with a soft material.
6. The button device of claim 1 , wherein the second spacer is formed along the edge portion.
7. The button device of claim 1 , wherein a plurality of such second spacers are formed at a plurality of places of the edge portion while being spaced apart.
8. The button device of claim 1 , wherein the piezoelectric body is a stack type piezoelectric body.
9. The button device of claim 1 , wherein a ratio of a length of the piezoelectric body to a length of the plate is 55% or more.