APPARATUS AND METHOD FOR DRIVING CAPACITIVE ELECTROMECHANICAL TRANSDUCTION APPARATUS

• US 20110227448A1
• Filed: 03/17/2011
• Published: 09/22/2011
• Est. Priority Date: 03/18/2010
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Majima, Masao, Kandori, Atsushi
• Granted Patent: US 9,072,429 B2
• Time in Patent Office: Days
• US Class Current: 310/300
• CPC Class Codes: A61B 5/0095 by applying light and detecting acoustic waves, i.e. photoacoustic measurements
• CPC Class Codes: B06B 1/0292 Electrostatic transducers, e.g. electret-type

Abstract

An apparatus is configured to drive a transduction apparatus including a cell with a first electrode and a second electrode disposed so as to oppose each other via a gap. The apparatus includes a timing detection unit and a control unit. The timing detection unit detects a timing of outputting of an electromagnetic wave from an electromagnetic wave source configured to output the electromagnetic wave to irradiate an object to be measured. The control unit drives and controls the transduction apparatus in synchronization with the detected timing such that the capacitive electromechanical transduction apparatus is put in a receiving state only for a period in which an acoustic wave generated in an inside of the object irradiated with the electromagnetic wave is received.

Claims

1. An apparatus configured to drive a transduction apparatus including a cell with a first electrode and a second electrode disposed so as to oppose each other via a gap, the apparatus comprising:

a timing detection unit configured to detect a timing of outputting of an electromagnetic wave from an electromagnetic wave source configured to output the electromagnetic wave to irradiate an object to be measured; and

a control unit configured to control the transduction apparatus in synchronization with the detected timing such that the transduction apparatus is put in a receiving state only for a period in which an acoustic wave generated in an inside of the object irradiated with the electromagnetic wave is received.

2. The apparatus according to claim 1, wherein the control unit switches the state of the transduction apparatus between the receiving state and a non-receiving state in synchronization with the detected timing periodically output from the electromagnetic wave source such that only the generated acoustic wave is received.

3. The apparatus according to claim 2, further comprising:

a current detection unit configured to detect a current induced in the first electrode; and

a path switching unit disposed between the current detection unit and the first electrode,

wherein the control unit controls the path switching unit in synchronization with the detected timing such that in the receiving state, the first electrode is connected to the current detection unit, while the first electrode is electrically disconnected from the current detection unit in the non-receiving state.

4. The apparatus according to claim 2, further comprising a current detection unit configured to detect a current induced in the first electrode,

wherein the control unit controls the current detection unit in synchronization with the detected timing such that the current detection unit detects the induced current in the receiving state while the current detection unit does not detect the induced current in the non-receiving state.

5. The apparatus according to claim 2, further comprising a potential application unit configured to adjust a potential difference between the first electrode and the second electrode,

wherein the control unit controls the potential application unit in synchronization with the detected timing such that the potential difference is smaller in the non-receiving state than in the receiving state and thus a current induced in the first electrode by a vibration of the second electrode is smaller in the non-receiving state than is induced in the receiving state.

6. A method of driving a transduction apparatus including a cell with a first electrode and a second electrode disposed so as to oppose each other via a gap, the method comprising:

detecting a timing of outputting of an electromagnetic wave from an electromagnetic wave source configured to output the electromagnetic wave to irradiate an object to be measured; and

controlling the transduction apparatus in synchronization with the detected timing such that the transduction apparatus is put in a receiving state only for a period in which an acoustic wave generated in an inside of the object to be measured irradiated with the electromagnetic wave is received.

7. The method according to claim 6, wherein the controlling is performed such that the state of the transduction apparatus is switched between the receiving state and a non-receiving state in synchronization with the detected timing periodically output from the electromagnetic wave source so as to receive only the generated acoustic wave.

8. The method according to claim 6, wherein the detecting is performed such that a driving signal of the electromagnetic wave source or an electromagnetic wave from the electromagnetic wave source is detected thereby detecting the timing of the outputting of the electromagnetic wave.

9. The method according to claim 6, wherein the controlling is performed such that the transduction apparatus is put in the non-receiving state for a first period following the timing of outputting the electromagnetic wave, in the receiving state for a second period following the first period, and in the non-receiving state for a third period following the second period.