Liquid discharge head, liquid discharge device, liquid discharge apparatus, method for manufacturing liquid discharge head

A liquid discharge head, comprising:

• a nozzle from which a liquid is to be discharged;
• a pressure chamber communicating with the nozzle;
• a substrate defining a side wall the pressure chamber;
• a diaphragm having a surface on the substrate, the diaphragm defining a part of a wall of the pressure chamber and a part of the nozzle;
• and
• a piezoelectric element on another surface of the diaphragm opposite to the surface of the diaphragm on the substrate, the piezoelectric element including:
• a piezoelectric portion configured to vibrate;
• and
• a pair of electrodes sandwiching the piezoelectric portion between the pair of electrodes, and
• an area of at least one of the pair of electrodes of the piezoelectric element is larger than an area of the pressure chamber in a plane of the diaphragm,
• wherein:
• the pair of electrodes includes:
• a first electrode on the diaphragm;
• and
• a second electrode farther than the first electrode from the substrate, and
• an area of the second electrode is larger than the area of the pressure chamber in the plane of the diaphragm,
• the pressure chamber and the piezoelectric element are circular in the plane of the diaphragm, and
• an outer diameter of the second electrode is larger than an outer diameter of the piezoelectric portion.

A method for manufacturing a liquid discharge head, the method comprising:

• forming a diaphragm on a substrate, one surface of the diaphragm is on the substrate;
• forming a piezoelectric element on another surface of the diaphragm, the piezoelectric element including a pair of electrodes and a piezoelectric portion between the pair of electrodes;
• forming wires to be electrically connected to the piezoelectric element;
• and
• forming a pressure chamber in the substrate while electrically connecting one of the pair of electrodes to a ground,
• wherein:
• the pair of electrodes includes:
• a first electrode on the diaphragm;
• and
• a second electrode farther than the first electrode from the substrate, and
• an area of the second electrode is larger than the area of the pressure chamber in the plane of the diaphragm,
• the pressure chamber and the piezoelectric element are circular in the plane of the diaphragm, and
• an outer diameter of the second electrode is larger than an inner diameter of the pressure chamber.