An ink jet head includes a pressure chamber connected to a nozzle, an actuator configured to cause liquid in the pressure chamber to be ejected from the nozzle by deforming a wall of the pressure chamber, and a drive circuit configured to apply voltage to the actuator to drive the actuator. When a droplet of the liquid is ejected from the nozzle, the voltage applied to the actuator is changed from a first value to a second value that causes the pressure chamber to expand, and then changed from a third value that is equal to the second value or between the first value and the second value to the first value after a time period , which is a primary natural oscillation period of the actuator when the pressure chamber and the nozzle are filled with the liquid.

A liquid droplet ejecting apparatus includes a liquid container including an upper opening for receiving liquid and a lower opening for supplying the liquid, the upper opening being larger than the lower opening, and a liquid ejection chip that is fixed to a lower surface of the liquid container, and includes a pressure chamber formed therein, a nozzle to eject liquid from the pressure chamber, and an actuator disposed adjacent to the nozzle. An opening of the pressure chamber is in fluid communication with the lower opening and is entirely included in an area of the lower opening.

Embodiments of the invention include a piezoelectric package integrated jet device. In one example, the jet device includes a vibrating membrane positioned between first and second cavities of an organic substrate, a piezoelectric material coupled to the vibrating membrane which acts as a first electrode, and a second electrode in contact with the piezoelectric material. The vibrating membrane generates fluid flow through an orifice in response to application of an electrical signal between the first and second electrodes.

Embodiments of the invention include a piezoelectric package integrated jet device. In one example, the jet device includes a vibrating membrane positioned between first and second cavities of an organic substrate, a piezoelectric material coupled to the vibrating membrane which acts as a first electrode, and a second electrode in contact with the piezoelectric material. The vibrating membrane generates fluid flow through an orifice in response to application of an electrical signal between the first and second electrodes.

According to an embodiment, an inkjet head includes a pressure cell structure. The pressure cell structure includes pressure cells, flow control paths, and slits. The flow control paths are formed on both the sides of the pressure cells, and control flow of ink flowing into the pressure cells. The slits are in communication with the pressure cells and the flow control paths. The width of the slit is smaller than the width of the pressure cell.

A method of forming a semiconductor structure includes providing a semiconductor substrate, forming a micro-electromechanical structure (MEMS) device in and/or on the semiconductor substrate, and providing a semiconductor chiplet comprising a circuit configured to provide input for the MEMS device and/or to process output from the MEMS device. The method further includes micro-transfer printing the semiconductor chiplet onto the semiconductor substrate, and connecting the circuit to the MEMS device.

An actuator includes a substrate, a vibration film, and a piezoelectric element. The substrate has a void space having a first width, defined by opposed inner walls, in a width direction. The vibration film is disposed over the substrate in a lamination direction perpendicular to the width direction. The vibration film serves as a part of a wall of the void space. The piezoelectric element is disposed over the vibration film in the lamination direction. The piezoelectric element is opposed to the void space of the substrate via the vibration film. The piezoelectric element has a second width smaller than the first width in the width direction. The piezoelectric element has outer ends, defining the second width, within the opposed inner walls of the void space in the width direction.