Abstract: An inkjet head comprising a nozzle, an ink passage in communication with the nozzle, a diaphragm provided at one part of the ink passage, and an electrode provided in opposition to the diaphragm whereby an electrical pulse is applied between the diaphragm and electrode to deform the diaphragm by means of electrostatic force, thereby ejecting ink droplets from the nozzle. The actuator contains at least a vibration chamber formed by the diaphragm and electrode, and is sealed or made airtight with the volume V so that the ratio between the actuator volume V and the volume .DELTA.V eliminated by a distortion of the diaphragm during ink-jet head drive is within the range 2.ltoreq.V/.DELTA.V.ltoreq.8.

Abstract: An ink jet head includes a common electrode formed on a semiconductor substrate. A charge is applied to the common electrode and an electrode disposed on another substrate in opposition to a diaphragm formed in the semiconductor substrate to electrostatically deform the diaphragm and eject ink. The common electrode comprises a single layer or multiple layer metallic coating forming ohmic contact on the semiconductor substrate. In addition, a group III or group V element is doped to a high concentration at the area on the semiconductor substrate where the common electrode is formed. The diaphragm can therefore vibrate at high speed. An ink jet head capable of high speed printing can be provided because supply and elimination of the charge to the diaphragm can be accomplished at high speed.

Abstract: A micropump for pumping liquid from an entry channel to an exit channel is disclosed. The micropump is formed in a semiconductor substrate sealed by two glass substrates. The micropump includes first and second chambers and flow channel means coupled between the two chambers. The micropump also includes a valve coupled between the entry channel and the first chamber. The valve includes a flexible valve membrane positioned closer to a second side of the semiconductor substrate than to its first side for causing the valve to be or not to be in contact with the second side of the semiconductor substrate for closing or opening the valve on the glass substrate. Additionally, the micropump includes a diaphragm forming part of a flexible wall of the second chamber and positioned closer to the second side of the semiconductor substrate than to its first side. The diaphragm is responsive to external pressure for causing liquid to be pumped from the entry channel to the exit channel.

Abstract: A micropump particularly suited for use in the fields of medicine and analysis includes a thin membrane plate sandwiched between a surface plate and a glass-made substrate. The intermediate membrane has an inlet valve and an outlet valve and the glass substrate has an inlet port and an outlet port, respectively connected to the corresponding valves. Between the valves formed in the thin membrane plate by means of etching, there is a diaphragm on which there is a piezoelectric element for detecting behavior of the diaphragm. Another micropump has an upper thin membrane plate member and a lower member. The upper member has the inlet valve and the lower member has the outlet valve. An intermediate glass substrate is inserted between the upper and the lower thin membrane plate member.