Piezoelectric device and an apparatus
A piezoelectric device comprises at least one element comprising at least one sheet of piezoelectric material. The element is mounted on a circuit board comprising at least one conductive layer having at least one opening. The element is located on the opening and supported by edges of the opening in such a manner that the opening extends laterally beyond the area of the sheet of piezoelectric material. The element is sandwiched between an overlay and the circuit board in such a manner that vibrations of the sheet of piezoelectric material are sufficient to cause vibration of the overlay.
1. A piezoelectric device ( 50 , 60 , 70 ) that comprises at least one element ( 58 ) that comprises at least one sheet ( 54 ) of piezoelectric material defining an area, characterized in that:
the element ( 58 ) has been mounted or placed on a circuit board ( 30 , 78 ) comprising at least one conductive layer ( 51 ; 701 , 702 , 703 , 704 ) with at least one opening ( 35 , 37 ; 81 , 82 ) in the conductive layer ( 51 ; 701 , 702 , 703 , 704 );
the element ( 58 ) being located on the opening ( 35 , 37 ; 81 , 82 ) and supported by edges of said at least one opening ( 35 , 37 ; 81 , 82 ), in such a manner that the opening ( 35 , 37 ; 81 , 82 ) extends laterally beyond the area of the sheet ( 54 ) of piezoelectric material; and
the element ( 58 ) is sandwiched between an overlay ( 503 ) and the circuit board ( 30 , 78 ) in such a manner that vibrations of the sheet ( 54 ) of piezoelectric material are sufficient to cause tactile vibration of the overlay ( 503 ).
2. The piezoelectric device ( 50 , 60 , 70 , 90 ) according to claim 1 , wherein: said at least one opening ( 35 , 37 ; 81 , 82 ) in the conductive layer ( 51 ; 702 ) comprises a circular part ( 35 ) and at least one extension ( 37 ; 81 , 82 ) to the circular part ( 35 ); and wherein the element ( 58 ) has been mounted on the circular part ( 35 ).
3. The piezoelectric device ( 50 , 60 , 70 , 90 ) of claim 2 , wherein: said extension ( 37 ) is a segment radially distancing from the circular part ( 35 ).
4. The piezoelectric device ( 50 , 60 , 70 , 90 ) of claim 2 , wherein: the opening ( 35 , 37 ; 81 , 82 ) comprises at least two extensions ( 37 ; 81 , 82 ) that are segments radially distancing from the opening ( 35 , 37 ; 81 , 82 ) and have been arranged in a symmetric manner around the opening ( 35 , 37 ; 81 , 82 ).
5. The piezoelectric device ( 50 , 60 , 70 , 90 ) of claim 2 , wherein: said extension ( 37 ; 81 , 82 ) comprises a circular opening that is concentric to the main opening, or a segment of a circle that is concentric to the main opening.
6. The piezoelectric device ( 50 , 60 , 70 , 90 ) of claim 1 claims, wherein: the at least one opening ( 81 , 82 ) comprises at least two extensions that have been configured to leave a tongue ( 83 ) of the conductive layer ( 51 ; 702 ) in between them, and wherein the element ( 58 ) has been fixed to the circuit board ( 30 , 78 ) at the position of the tongue ( 83 ).