Patent ID: 8480210

Claim:
A liquid jet head, comprising: an actuator substrate comprising: a plurality of grooves aligned in parallel to each other in a surface of the actuator substrate; partition walls separating the plurality of grooves from each other, each of the partition walls having opposite side surfaces each confronting a side surface of an adjacent partition wall; and drive electrodes disposed on the confronting side surfaces of the partition walls to form a plurality of pairs of confronting drive electrodes, the drive electrodes of each pair of confronting drive electrodes being disposed so that they are not connected to each other, the drive electrodes not being formed on bottom surface of the grooves; a cover plate bonded onto the surface of the actuator substrate so as to cover the plurality of grooves; and a nozzle plate comprising nozzles communicating with respective ones of the plurality of grooves, the nozzle plate being bonded onto an end surface of the actuator substrate; wherein the actuator substrate comprises a drive region for driving the drive electrodes so as to deform the partition walls to cause liquid filling the plurality of grooves to jet from the nozzles; wherein, in the drive region, each of the partition walls is made of a piezoelectric material on a top surface side situated above substantially half a height from the bottom surface of each of the plurality of grooves to a top surface of each of the partition walls, and is made of a low-permittivity material, which is lower in permittivity than the piezoelectric material, on a bottom surface side situated below substantially half the height; and wherein, in the drive region, each of the drive electrodes is placed so as to extend across each side surface of each of the partition walls made of the piezoelectric material and each side surface of each of the partition walls made of the low-permittivity material.