Thin piezoelectric film element, process for the preparation thereof and ink jet recording head using thin piezoelectric film element

A thin piezoelectric film element comprising a piezoelectric film made of a polycrystalline substance and an upper electrode and a lower electrode arranged with said piezoelectric film interposed therebetween, wherein said lower electrode is made of a compound of platinum with an oxide of the metal element constituting said piezoelectric film;

• wherein the grain boundary of the crystalline substance constituting said lower electrode is present substantially perpendicular to the surface of said piezoelectric film;
• and
• wherein the vertical width of the crystal grains constituting said lower electrode is greater than the horizontal width of the crystal grains constituting said lower electrode.

A thin piezoelectric film element comprising a piezoelectric film made of a polycrystalline substance having a thickness of from 0.5 to 25 .mu.m and two electrodes arranged with said piezoelectric film interposed therebetween, wherein said piezoelectric film has pores incorporated therein and said pores have an average diameter of not less than 0.01 .mu.m and a surface density of not less that 0.3%, and

• wherein said pores have an average diameter of not more than 0.01 .mu.m and a surface density of not more than 5%.

A thin piezoelectric film element comprising a piezoelectric film made of a polycrystalline substance and an upper electrode and a lower electrode arranged with said piezoelectric film interposed therebetween, wherein said crystalline substance constituting said piezoelectric film is formed substantially perpendicular to the surface of said electrodes;

• and
• wherein the vertical width of crystal grains constituting said lower electrode is greater than the horizontal width of crystal grains constituting said lower electrode.

A thin piezoelectric film element comprising a piezoelectric film made of a polycrystalline substance and an upper electrode and a lower electrode arranged with said piezoelectric film interposed therebetween, wherein said lower electrode is made of a compound of platinum with an oxide of the metal element constituting said piezoelectric film and

• wherein the vertical width of crystal grains constituting said lower electrode is greater than the horizontal width of crystal grains constituting said lower electrode.

A thin piezoelectric film element comprising a piezoelectric film made of a polycrystalline substance and an upper electrode and a lower electrode arranged with said piezoelectric film interposed therebetween, wherein said lower electrode is made of a compound of platinum with an oxide of the metal element constituting said piezoelectric film and

• wherein the relationship between the vertical width and the horizontal width of crystal grains constituting said lower electrode is from not less than 1/10 to not more than 1/3 as calculated in terms of the ratio of horizontal width to vertical width.