Multi-frequency transmission/reception apparatus

• US 7,443,081 B2
• Filed: 04/11/2002
• Issued: 10/28/2008
• Est. Priority Date: 04/13/2001
• Status: Expired due to Term

• Current Assignee: Furuno Electric Co, Ltd
• Original Assignee: Furuno Electric Co, Ltd
• Inventors: Yamaguchi, Takeharu, Kamei, Kazuhiko, Suetoshi, Ryouichi
• Primary Examiner(s): Dougherty; Thomas M
• Application Number:
  US10/471,700
• Publication Number:
  US 20040090148A1
• Time in Patent Office: 2,392 Days
• Field of Search: 310/322, 310/334, 310/333
• US Class Current: 310/334
• CPC Class Codes: B06B 1/06 operating with piezoelectric effect or with electrostriction piezoelectric or electrostrictive devices per se H10N30/00
• CPC Class Codes: B06B 1/0622 on one surface
• CPC Class Codes: B06B 2201/74 Underwater
• CPC Class Codes: G01S 15/96 for locating fish
• CPC Class Codes: G01S 7/521 Constructional features

Abstract

The invention provides a multi-frequency transducer capable of obtaining desired directivity regardless of frequencies. Parallelepiped-shaped transducer elements (1) are used as transducer elements and a plurality of such transducer elements (1) are arranged in an array. The transducer elements (1) are caused to resonate using a resonant frequency in fundamental vibration mode and a resonant frequency in harmonic vibration mode determined by the dimensions (A, B) of a short edge (1a) and a long edge (1b) perpendicular to a longitudinal edge (1c) of each transducer element (1) to transmit and receive at multiple frequencies. The angle of directivity (θ) of the transducer elements is controlled by the dimension (C) of the longitudinal edge which is set to a value which does not affect resonance in either the fundamental vibration mode or the harmonic vibration mode.

Claims

1. An ultrasonic transducer array comprising:

a plurality of transducer elements, each transducer element further comprising;

a radiating surface;

two electrode surfaces coupled to the radiating surface, wherein transmit signals are applied to said electrode surfaces; and

an additional surface coupled to the two electrode surfaces,

wherein each transducer element vibrates, in response to said transmit signals, at a predetermined plurality of resonant frequencies based upon dimensions of an edge of the radiating surface that is not in common with the electrode surface and an edge of the electrode surface that is not in common with the radiating surface, further wherein the dimensions are selected so that a combination vibration mode does not occur,

wherein the radiating surface transmits an acoustic wave resonating at the predetermined plurality of resonant frequencies and propagates with a predetermined angle of directivity, further wherein the angle of directivity is based upon a dimension of an edge common to the radiating surface and the electrode surface,

wherein the dimension of the edge common to the radiating surface and the electrode surface is set to be larger than at least the edge of the radiating surface that is not in common with the electrode surface, and the edge of the electrode surface that is not in common with the radiating surface, to a degree that does not influence resonance in either a fundamental vibration mode or a harmonic vibration mode,

wherein the transducer elements are arranged in an array so that each radiating surface lies in a common surface.

2. The ultrasonic transducer according to claim 1, further comprising an electrode attached to each electrode surface to energize the transducer element.

3. The ultrasonic transducer according to claim 1, wherein the ratio of the edge of the radiating surface not in common with the electrode surface and the edge of the electrode surface not in common with the radiating surface is less than 0.5.

4. The ultrasonic transducer according to claim 1, wherein each electrode surface of the plurality of transducer elements is energized by an AC signal.

5. The ultrasonic transducer according to claim 1, wherein the ratio of the edge common to the radiating surface and the electrode surface, and the edge of the electrode surface not in common with the radiating surface is larger than substantially 3.