Ultrasonic transducer and manufacturing method therefor

• US 6,308,389 B1
• Filed: 12/08/1999
• Issued: 10/30/2001
• Est. Priority Date: 12/09/1998
• Status: Expired due to Term

• Current Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Tezuka, Satoru
• Primary Examiner(s): Young, Lee
• Assistant Examiner(s): Kim, Paul D
• Application Number:
  US09/456,402
• Time in Patent Office: 692 Days
• Field of Search: 29/253.5, 295/94, 296/031.3, 296/031.4, 296/091, 296/031.6, 297/59, 298/83, 264/263, 264/292.14, 264/292.16
• US Class Current: 29/25.35
• CPC Class Codes: A61B 8/4494 characterised by the arrangement of the transducer elements devices for short-range imaging using particular transducer elements arrangements under G01S15/8909; arrangements of transducers in generation of mechanical vibrations of infrasonic, sonic or ultrasonic frequency B06B1/0607
• CPC Class Codes: B06B 1/0629 Square array
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/49043 Depositing magnetic layer or coating
• CPC Class Codes: Y10T 29/49044 Plural magnetic deposition layers
• CPC Class Codes: Y10T 29/49048 Machining magnetic material [e.g., grinding, etching, polishing]
• CPC Class Codes: Y10T 29/4908 Acoustic transducer
• CPC Class Codes: Y10T 29/49128 Assembling formed circuit to base
• CPC Class Codes: Y10T 29/49137 Different components
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base
• CPC Class Codes: Y10T 29/49158 with molding of insulated base
• CPC Class Codes: Y10T 29/4922 with molding of insulation
• CPC Class Codes: Y10T 29/53261 Means to align and advance work part

Abstract

This invention relates to a method of manufacturing an ultrasonic transducer. First, a plurality of printed boards in each of which a plurality of leads are formed in a line are stacked. The end portions of the leads protrude from each printed board. These lead end portions are inserted into a plurality of lead holes of an alignment jig. The plurality of printed boards are buried in the back surface of this alignment jig, and a backing layer is formed by resin molding. After that, the alignment jig is removed from the surface of the backing layer, and the surface of the backing layer is flattened. Since the end portions of the leads are exposed to this flattened surface of the backing layer, discrete electrodes formed on the back surfaces of transducer elements are electrically connected to these lead end portions. The accuracy of lead arrangement is thus improved by the use of the alignment jig. This reduces alignment errors of leads with respect to the discrete electrodes of the transducer elements.

Claims

1. A method of manufacturing an ultrasonic transducer, comprising the steps of:

stacking a plurality of printed boards in each of which a plurality of leads are formed in a line, end portions of said leads protruding from said printed boards;

inserting the end portions of said leads into a plurality of lead holes or lead slits of an alignment jig, said plurality of lead holes or lead slits being formed in said alignment jig;

forming a backing layer by resin molding on a back surface of said alignment jig, said plurality of printed boards being buried in said backing layer;

cutting said alignment jig, the end portions of said leads being exposed to a surface of said cut alignment jig; and

forming a transducer element array on the surface of said alignment jig, said transducer element array comprising a plurality of transducer elements arrayed in a matrix, and discrete electrodes being formed on back surfaces of said transducer elements and electrically connected to the end portions of said leads.

2. A method according to claim 1, further comprising the step of filling gaps in said lead holes or lead slits with a conductive resin after said leads are inserted into said lead holes or lead slits.

3. A method according to claim 1, further comprising the step of forming a thin metal film on the flattened surface of said backing layer after said alignment jig is removed and the surface of said backing layer is flattened.

4. A method according to claim 3, further comprising the step of dividing said thin metal film in accordance with said plurality of leads after said thin metal film is formed.

5. A method according to claim 1, wherein the step of forming said transducer element array on the surface of said backing layer comprises the substeps of:

attaching a piezoelectric plate to the surface of said backing layer, electrode layers being formed on front and back surfaces of said piezoelectric plate;

forming an acoustic matching layer on the front surface of said piezoelectric plate; and

forming grooves crosswise which extend from a surface of said acoustic matching layer to an outermost portion of said backing layer.

6. A method according to claim 5, wherein said acoustic matching layer has conductivity.

7. A method according to claim 5, wherein the step of forming said transducer element array on the surface of said backing layer further comprises the substep of forming a grounding electrode on the surfaces of said divided acoustic matching layers.

8. A method according to claim 7, wherein said grounding electrode comprises a metal layer and a resin layer.

9. A method according to claim 7, wherein said grounding electrode is comprised of a metal foil.

10. A method according to claim 1, wherein the step of forming a transducer element array on the surface of said backing layer comprises the substeps of:

mounting a piezoelectric plate on the surface of said backing layer, said piezoelectric plate having front and back surfaces on which electrode layers are respectively formed;

forming vertical and horizontal grooves deep enough to reach a surface layer portion of said backing layer from the surface of said piezoelectric plate in order to divide the piezoelectric plate;

forming a grounding electrode on the surface of said divided piezoelectric plate; and

forming an acoustic matching layer on a surface of said grounding electrode.

11. A method according to claim 10, wherein said grounding electrode comprises a metal layer and a resin layer.

12. A method according to claim 10, wherein said grounding layer is comprised of a metal foil.

13. A method according to claim 1, wherein electronic circuits are formed together with said leads on said printed boards.

14. A method according to claim 1, wherein said alignment jig has said lead holes arranged in a matrix, and said leads are fitted in said lead holes or lead slits, respectively.

15. A method according to claim 1, wherein said alignment jig has said or lead slits arranged parallel to each other, and a plurality of leads are fitted in one of said lead holes or lead slits.

16. A method according to claim 1, wherein said lead hole or lead slit of said alignment jig is a blind hole or slit.

17. A method according to claim 1, wherein said alignment jig has a multilayered structure made of a plurality of different materials.