Piezoelectric substrate, piezoelectric element, liquid discharge head and liquid discharge apparatus

Abstract

A piezoelectric substrate of a perovskite-type oxide is expressed by a general formula of ABO 3 having a laminate structure of a single crystal structure or a uniaxial crystal structure expressed by (Pb 1-x M x ) xm (Zr y Ti 1-y )O 3 (where M represents an element selected from La, Ca, Ba, Sr, Bi, Sb and W) and the laminate structure has a layered first crystal phase having a crystal structure selected from the tetragonal structure, the rhombohedral structure, the pseudocubic structure and the monoclinic structure, a layered second crystal phase having a crystal structure different from the crystal structure of said first crystal phase and a boundary layer arranged between said first crystal phase and said second crystal phase with a crystal structure gradually changing in a width direction of layer.

1 . A piezoelectric substrate of a perovskite-type oxide expressed by a general formula of ABO 3  having a laminate structure of a single crystal structure or a uniaxial crystal structure expressed by (Pb 1-x M x ) xm (Zr y Ti 1-y )O 3  (where M represents an element selected from La, Ca, Ba, Sr, Bi, Sb and W), the laminate structure having: 
 a layered first crystal phase having a crystal structure selected from a tetragonal structure, a rhombohedral structure, a pseudocubic structure and a monoclinic structure;    a layered second crystal phase having a crystal structure selected from the tetragonal structure, the rhombohedral structure, the pseudocubic structure and the monoclinic structure but different from the crystal structure of said first crystal phase; and    a boundary layer arranged between said first crystal phase and said second crystal phase with a crystal structure gradually changing in a width direction of layer.    
     
     
         2 . The piezoelectric substrate according to  claim 1 , wherein 
 the requirement of 0.45≦y≦1 is satisfied.    
     
     
         3 . A piezoelectric element comprising a piezoelectric substrate and a pair of electrodes; 
 said piezoelectric substrate being a perovskite-type oxide expressed by a general formula of ABO 3  having a laminate structure of a single crystal structure or a uniaxial crystal structure expressed by (Pb 1-x M x ) xm (Zr y Ti 1-y )O 3  (where M represents an element selected from La, Ca, Ba, Sr, Bi, Sb and W), the laminate structure having:    a layered first crystal phase having a crystal structure selected from a tetragonal structure, a rhombohedral structure, a pseudocubic structure and a monoclinic structure;    a layered second crystal phase having a crystal structure selected from the tetragonal structure, the rhombohedral structure, the pseudocubic structure and the monoclinic structure but different from the crystal structure of said first crystal phase; and    a boundary layer arranged between said first crystal phase and said second crystal phase with a crystal structure gradually changing in a width direction of layer.    
     
     
         4 . A liquid discharge head comprising separate liquid chambers communicating to respective discharge ports and piezoelectric elements arranged respectively in the separate liquid chambers and having a piezoelectric substrate and a pair of electrodes and the head discharging liquid in the separate liquid chambers from the respective discharge ports; 
 said piezoelectric substrate being a perovskite-type oxide expressed by a general formula of ABO 3  having a laminate structure of a single crystal structure or a uniaxial crystal structure expressed by (Pb 1-x M x ) xm (Zr y Ti 1-y )O 3  (where M represents an element selected from La, Ca, Ba, Sr, Bi, Sb and W), the laminate structure having:    a layered first crystal phase having a crystal structure selected from a tetragonal structure, a rhombohedral structure, a pseudocubic structure and a monoclinic structure;    a layered second crystal phase having a crystal structure selected from the tetragonal structure, the rhombohedral structure, the pseudocubic structure and the monoclinic structure but different from the crystal structure of said first crystal phase; and    a boundary layer arranged between said first crystal phase and said second crystal phase with a crystal structure gradually changing in a width direction of layer.    
     
     
         5 . A liquid discharge apparatus having a liquid discharge head for discharging liquid, comprising: 
 each of the piezoelectric elements for generating energy of liquid discharge having a piezoelectric substrate and a pair of electrodes;    said piezoelectric substrate being a perovskite-type oxide expressed by a general formula of ABO 3  having a laminate structure of a single crystal structure or a uniaxial crystal structure expressed by (Pb 1-x M x ) xm (Zr y Ti 1-y )O 3  (where M represents an element selected from La, Ca, Ba, Sr, Bi, Sb and W), the laminate structure having:    a layered first crystal phase having a crystal structure selected from a tetragonal structure, a rhombohedral structure, a pseudocubic structure and a monoclinic structure;    a layered second crystal phase having a crystal structure selected from the tetragonal structure, the rhombohedral structure, the pseudocubic structure and the monoclinic structure but different from the crystal structure of said first crystal phase; and    a boundary layer arranged between said first crystal phase and said second crystal phase with a crystal structure gradually changing in a width direction of layer.