Capacitive electromechanical transducer

Abstract

The present invention relates to an electromechanical transducer capable of arbitrarily varying the amount of deflection of a vibrating membrane for every element. The electromechanical transducer includes a plurality of elements including at least one cell that includes a first electrode and a second electrode opposed to the first electrode with a gap sandwiched therebetween and a direct-current voltage applying unit configured to be provided for each element and to separately apply a direct-current voltage to the first electrodes in each element. The first electrodes and the second electrodes are electrically separated for every element.

1 . An electromechanical transducer comprising:
 an element including a plurality of cells, the cell including a first electrode region and a second electrode region opposed to the first electrode region with a gap therebetween, and the element having a first electrode including a plurality of the first electrode regions and a second electrode including a plurality of the second electrode regions; and   a substrate including a through wiring line, wherein   one of the first electrode of the element and   the second electrodes of the element is electrically connected to the through wiring line.   
     
     
         2 . The electromechanical transducer according to  claim 1 , wherein the number of the through wiring line is the same as that of the elements. 
     
     
         3 . The electromechanical transducer according to  claim 1 , further comprising:
 a voltage applying unit configured to separately cause a potential difference between the first electrode and the second electrode for each element.   
     
     
         4 . The electromechanical transducer according to  claim 3 ,
 wherein the voltage applying unit comprises a first voltage applying unit configured to separately apply a direct voltage to the first electrode for each element.   
     
     
         5 . The electromechanical transducer according to  claim 4 , wherein the voltage applying unit comprises an alternating voltage superimposing unit configured to superimpose an alternating voltage on the direct-current voltage. 
     
     
         6 . The electromechanical transducer according to  claim 4 , further comprising:
 wherein the voltage applying unit comprises a second voltage applying unit configured to separately apply an alternating voltage to the second electrode for each element.   
     
     
         7 . The electromechanical transducer according to  claim 3 ,
 wherein the voltage applying unit comprises a second voltage applying unit configured to separately apply an alternating voltage to the second electrodes for each element.   
     
     
         8 . The electromechanical transducer according to  claim 1 , further comprising:
 a current detecting unit configured to separately detect a current output from the second electrode for each element.   
     
     
         9 . The electromechanical transducer according to  claim 4 , further comprising:
 a control-signal generating unit configured to instruct a direct voltage to be applied to the first voltage applying unit on the basis of the current detected by the current detecting unit.   
     
     
         10 . The electromechanical transducer according to  claim 9 ,
 wherein the voltage applying unit comprises an alternating voltage superimposing unit configured to superimpose an alternating voltage on the direct-current voltage,   wherein a current caused by the alternating voltage is detected by the current detecting unit and the direct voltage is instructed to the control-signal generating unit on the basis of the current output from the alternating voltage.   
     
     
         11 . The electromechanical transducer according to  claim 10 , further comprising:
 a signal switching unit configured to switch an output signal from the current detecting unit so as to be connected to the control-signal generating unit in detection of a current output from the alternating voltage and so as not to be connected to the control-signal generating unit in detection of a current output from a vibration of a vibrating membrane.   
     
     
         12 . The electromechanical transducer according to  claim 7 , further comprising:
 a current detecting unit configured to separately detect a current output from the second electrode for each element.   
     
     
         13 . The electromechanical transducer according to  claim 12 , further comprising:
 a protection unit configured to protect the current detecting unit from the alternating voltage generated by the second voltage applying unit.   
     
     
         14 . The electromechanical transducer according to  claim 1 ,
 wherein the through wiring line in an element are electrically separated from the through wiring line in other element.   
     
     
         15 . The electromechanical transducer according to  claim 1 , wherein the at least one cell further includes a vibrating membrane on which at least one of the first electrode and the second electrode is formed. 
     
     
         16 . The electromechanical transducer according to  claim 1 , wherein the at least one of the first electrode and the second electrode serves as a vibrating membrane. 
     
     
         17 . The electromechanical transducer according to  claim 3 , wherein the electromechanical transducer including a plurality of elements, and wherein the voltage applying unit is configured to apply a voltage for each element so as to reduce a variation in transmission characteristics of the ultrasonic waves between the elements according to the current detected by the current detecting unit. 
     
     
         18 . The electromechanical transducer according to  claim 3 , wherein the electromechanical transducer including a plurality of elements, and wherein the voltage applying unit is configured to apply a voltage for each element so as to reduce a variation in reception characteristics of the ultrasonic waves between the elements according to the current detected by the current detecting unit. 
     
     
         19 . The electromechanical transducer according to  claim 3 , wherein the electromechanical transducer including a plurality of elements, and wherein the voltage applying unit is configured to apply a voltage for each element so as to reduce a variation in an amount of deflection between the elements according to the current detected by the current detecting unit. 
     
     
         20 . The electromechanical transducer according to  claim 1 , wherein the other of the first electrode of the element and the second electrode of the element is common electrode.