{HEAD ~ a piezoelectric substrate grinding step} of grinding {TAIL ~ a lower surface} of the piezoelectric substrate, the lower surface being opposite to an upper surface on which the ejection grooves and the non ejection grooves are formed, to allow the non ejection grooves to penetrate the piezoelectric substrate from the upper surface through the lower surface thereof 
{ HEAD ~ a piezoelectric substrate grinding step } of grinding { TAIL ~ a lower surface } of the piezoelectric substrate , the lower surface being opposite to an upper surface on which the ejection grooves and the non ejection grooves are formed , to allow the non ejection grooves to penetrate the piezoelectric substrate from the upper surface through the lower surface thereof
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH