Layered unit provided with piezoelectric ceramics, method for producing the same, and ink jet printing head employing the same

摘要

A layered unit provided with piezoelectric ceramics having an increased adhesive strength while lowering cell content in an adhesive layer, a method for producing the layered unit, and an ink jet printing head incorporated with such layered unit having improved ink emission precision and durability as well as suppressing occurrence of assembly failure at the time of producing the ink jet printing head. The layered unit has a first member made of piezoelectric ceramics, a second member which is placed over the first member, and an adhesive layer which is formed between the first member and the second member to adhere the first member and the second member. A joint surface of the first member to be jointed to the second member is formed with a multitude of recesses. A sum of opening areas of the recesses occupies 50% or more relative to a total surface area of the joint surface of the first member. Alternatively, a crystalline part comprising the joint surface of the first member is formed with a multitude of microprotrusions.