PIEZOELECTRIC DEVICE, LIQUID INJECTION HEAD, AND LIQUID INJECTION APPARATUS

To provide a piezoelectric device, a liquid injection head, and a liquid injection apparatus that can prevent destruction of a piezoelectric actuator.SOLUTION: A piezoelectric device comprises: a substrate 10 in which a plurality of concave parts 12 are formed; a diaphragm 50; and a piezoelectric actuator 300 that includes a first electrode 60, a piezoelectric layer 70, and a second electrode 80. The piezoelectric actuator 300 has a plurality of active parts 310. Any one electrode of the first electrode 60 and the second electrode 70 forms individual electrodes of the active parts 310. The other electrode forms a common electrode of the active parts 310. The first electrode 60 and the second electrode 80 are electrically connected with a drive circuit 120 having a switching element that drives the piezoelectric actuator 300. In a longitudinal direction Y of the concave parts 12, the piezoelectric layer 70 is extended to the outside of the concave parts 12. In the longitudinal direction Y of the concave parts 12, at least one end of the common electrode is present in the concave parts 12.SELECTED DRAWING: Figure 5 【課題】圧電アクチュエーターの破壊を抑制することができる圧電デバイス、液体噴射ヘッド及び液体噴射装置を提供する。【解決手段】複数の凹部１２が形成された基板１０と、振動板５０と、第１電極６０と圧電体層７０と第２電極８０とを備える圧電アクチュエーター３００と、を備え、前記圧電アクチュエーター３００は、活性部３１０を複数有し、前記第１電極６０及び前記第２電極７０の何れか一方の電極は、前記活性部３１０の個別電極を構成し、他方の電極は、前記活性部３１０の共通電極を構成し、前記第１電極６０及び前記第２電極８０は、前記圧電アクチュエーター３００を駆動するスイッチング素子を有する駆動回路１２０と電気的に接続され、前記凹部１２の長手方向Ｙにおいて前記圧電体層７０は、前記凹部１２の外側まで延在され、前記凹部１２の長手方向Ｙにおいて、前記共通電極の少なくとも一方の端部は、前記凹部１２内に存在する。【選択図】図５