Piezoelectric device and acousto-electric transducer and method for manufacturing the same

Abstract

A lens shape piezoelectric device which is thinner than the manufacture limit thickness, which is conventionally difficult to manufacture, and a method for manufacturing the same. The piezoelectric device has a oscillation part having at least two steps where one side thereof is planar and the opposite side is thickest at a peripheral holding portion and thinner toward the central portion. A piezoelectric element of another embodiment has an oscillation part of at least two steps where the peripheral holding portion is thickest on both sides and the thickness decreases toward the central portion. In these piezoelectric devices, at least one side of the thinnest central portion of the oscillation part has a convex lens shape. A pair of electrodes are vacuum deposited in the center of these oscillation parts on both sides, and a gold wire is led as a lead wire from each electrode.

1 . A manufacturing method of said acousto-electric transducer, which makes the oscillation part of a final thickness and target profile, after the final profile is formed on the surface of piezoelectric material which is thicker than the final thickness, and the surface of said piezoelectric material is reactively etched and homogeneously decreasing the thickness from both ends toward the central region of said piezoelectric material.  
   
   
       2 . A manufacturing method of said piezoelectric device, which makes the oscillation part of a final thickness and target profile inside the central region of a rod in hollow cylindrical shape, after the final profile is formed on the surface of a rod made from the piezoelectric material, and the surface of said rod except the wall of said rod is processed by the dry etching and homogeneously decreasing the thickness from both ends toward the central region of said rod.  
   
   
       3 . A manufacturing method of said acousto-electric transducer, which makes the oscillation part of a final thickness and target profile, after the final profile is formed on the surface of piezoelectric material which is thicker than the final thickness, and the surface of said piezoelectric material is processed by the dry etching and homogeneously decreasing the thickness from both ends toward the central region of said piezoelectric material.  
   
   
       4 . A manufacturing method of said piezoelectric device, which makes the oscillation part of a final thickness and target profile inside the central region of a rod in hollow cylindrical shape, after the final profile is formed on the surface of a rod made from the piezoelectric material, and the surface of said rod except the wall of said rod is processed by the dry etching and homogeneously decreasing the thickness from both ends toward the central region of said rod.  
   
   
       5 . A manufacturing method of said piezoelectric device, which makes the piezoelectric material in a lens shape identical to an auxiliary blank, after said auxiliary blank in the final lens shape is closely attached to both ends of the rod made from the piezoelectric material, and the surface of said auxiliary blank attached to the rod is processed by the dry etching, and then the surface of said auxiliary blank is shaved at first and next the surface of the piezoelectric material.  
   
   
       6 . A manufacturing method of said piezoelectric device, which makes the piezoelectric material in a lens shape with a holder identical to an auxiliary blank, after said auxiliary blank in the final lens shape is closely attached to both ends of the rod made from the piezoelectric material, and the surface of said auxiliary blank attached to the rod is processed by the dry etching, and then the surface of said auxiliary blank is shaved at first, and next the surface of the piezoelectric material is also shaved.