| 摘要 |
PROBLEM TO BE SOLVED: To eliminate a wiring area and a pad area for leading out pads by taking discrete electrodes out from the rear face side of an electrode substrate, and reduce costs of an ink jet head by making a chip size small. SOLUTION: A driving voltage is impressed between a diaphragm 13 and the discrete electrode 23 formed on the electrode substrate 21, whereby the diaphragm 13 is deformed by an electrostatic force. Ink in a liquid chamber 12 is consequently pressured and ink liquid drops are discharged from a nozzle 33. A through hole 26 is formed to the electrode substrate 21 to reach the discrete electrode 23. A conductive film (Cr-Cu-Au alloy) 29 is formed to an inner wall and the periphery of the through hole 26, and a Pb-Sn alloy 30 is formed on the conductive film 29. When the electrode substrate 21 is heated in an H2 atmosphere to a temperature not lower than a melting point of a solder, a bump 31 is formed by a surface tension of the solder itself.
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