JP-7856143-B2 - Ultrasonic transducer and method for manufacturing the same

Inventors

• 松下 智昭
• 島本 隆之

Assignees

• 株式会社村田製作所

Dates

Publication Date

20260511

Application Date

20230227

Priority Date

20220419

Claims (5)

1. A bottomed cylindrical case having a bottom and side walls, A piezoelectric element having a first main surface and a second main surface, wherein the second main surface is attached to the bottom of the case on the inside, A terminal member having a first end positioned inside the case and a second end positioned outside the case, A strip-shaped flexible printed circuit board electrically connects the piezoelectric element and the first end of the terminal member, A first filler material is filled to fill the bottom of the case, The case comprises a second filler material filled so as to fill the first filler material inside the case, The aforementioned flexible printed circuit board is Having a first electrode electrically connected to the piezoelectric element, and a first surface portion extending while in contact with the first main surface of the piezoelectric element, A second surface portion curves upward from the edge of the first surface portion adjacent to the side wall portion and extends along the side wall portion of the case, The terminal member has a second electrode electrically connected to the first end, and includes a third surface portion that is bent in an S-shape from the upper end of the second surface portion and faces the first surface portion at a distance from it, The first surface and at least the portion of the second surface closest to the first surface are embedded in the first filler. The third surface is embedded in the second filler, An ultrasonic transducer in which the ratio of the height of the first filler to the height of the case in the height direction perpendicular to the bottom is 0.3 times or more and 0.7 times or less.
2. The ultrasonic transducer according to claim 1, wherein the second surface portion is in direct contact with the side wall portion.
3. The ultrasonic transducer according to claim 1 or 2, wherein the first electrode and the second electrode are arranged on either the front or back surface of the flexible printed circuit board.
4. The ultrasonic transducer according to claim 1, wherein the curvature of the second surface portion located at the boundary with the edge of the first surface portion of the flexible printed circuit board is 0.8 (1/mm) or more and 2.9 (1/mm) or less.
5. A piezoelectric element having a first main surface and a second main surface, A bottomed cylindrical case having a bottom and side walls, A terminal member having a first end and a second end, A strip-shaped flexible printed circuit board having a first electrode and a second electrode, electrically connecting the piezoelectric element and the terminal member to each other, The first filling material is filled inside the case, A method for manufacturing an ultrasonic transducer comprising a second filler material filled inside the case, A step of connecting the first electrode of the flexible printed circuit board to the first main surface of the piezoelectric element, The steps include: attaching the second main surface of the piezoelectric element to which the flexible printed circuit board is connected to the bottom, and positioning the second electrode on the outside of the case while bending the flexible printed circuit board in contact with the side wall; A step of filling the bottom of the case with the first filler material to fix a part of the flexible printed circuit board, The process of connecting the second electrode of the flexible printed circuit board to the first end of the terminal member on the outside of the case, A step of bending the portion of the flexible printed circuit board that is exposed from the first filler, with the second end of the terminal member positioned outside the case and the first end of the terminal member to which the flexible printed circuit board is connected positioned inside the case, The process includes filling the case with the first filler and filling the flexible printed circuit board with a second filler so as to fill the portion of the flexible printed circuit board that is exposed from the first filler and bent , A method for manufacturing an ultrasonic transducer, comprising the step of filling the flexible printed circuit board with the first filler to fix the part of the flexible printed circuit board, wherein the part of the flexible printed circuit board is filled with the first filler .

Description

This invention relates to an ultrasonic transducer and a method for manufacturing the same. Prior art document disclosing the configuration of an ultrasonic sensor is International Publication No. 2013/051525 (Patent Document 1). The ultrasonic sensor described in Patent Document 1 comprises a case, a piezoelectric element, pin terminals, a strip-shaped flexible substrate, and a vibration damping material. The case has a bottom plate and side walls. The piezoelectric element is arranged on the bottom plate inside the case. One end of the pin terminal is located inside the opening of the case, and the other end is located outside the case. The flexible substrate has a first end connected to one end of the pin terminal and a second end connected to the piezoelectric element. The vibration damping material seals one end of the pin terminal and the flexible substrate inside the case. International Publication No. 2013/051525 This is a longitudinal cross-sectional view of an ultrasonic transducer according to Embodiment 1 of the present invention.This is a flowchart showing a method for manufacturing an ultrasonic transducer according to Embodiment 1 of the present invention.This is a cross-sectional view showing the state in which the piezoelectric element and the flexible printed circuit board of the ultrasonic transducer according to Embodiment 1 of the present invention are connected.This is a longitudinal cross-sectional view showing the piezoelectric element of the ultrasonic transducer according to Embodiment 1 of the present invention attached to the bottom of the case.This is a longitudinal cross-sectional view showing the state in which the first filler material of the ultrasonic transducer according to Embodiment 1 of the present invention is filled inside the case.This is a longitudinal cross-sectional view showing a state in which a terminal member of an ultrasonic transducer according to Embodiment 1 of the present invention is connected to a flexible printed circuit board.This is a longitudinal cross-sectional view showing a state in which the first end of the terminal member is positioned inside the case by bending the flexible printed circuit board of the ultrasonic transducer according to Embodiment 1 of the present invention.This is a longitudinal cross-sectional view of an ultrasonic transducer according to Embodiment 2 of the present invention. The ultrasonic transducers according to each embodiment of the present invention will be described below with reference to the figures. In the following descriptions of the embodiments, the same or corresponding parts in the figures will be denoted by the same reference numerals, and their descriptions will not be repeated. In the drawings, the direction along the bottom of the case is referred to as the DR1 direction, and the direction of the case's height is referred to as the DR2 direction. (Embodiment 1) Figure 1 is a longitudinal cross-sectional view of an ultrasonic transducer according to Embodiment 1 of the present invention. As shown in Figure 1, the ultrasonic transducer 100 according to this embodiment is, for example, an ultrasonic sensor. As shown in Figure 1, the ultrasonic transducer 100 comprises a bottomed cylindrical case 110, a piezoelectric element 120, a terminal member 130, a strip-shaped flexible printed circuit board 140, a first filler material 150, and a second filler material 160. The case 110 has a bottom portion 111 and side wall portions 112. In this embodiment, the bottom portion 111 has a disc shape when viewed from the DR2 direction. The diameter of the bottom portion 111 is, for example, 14.0 mm or more and 15.5 mm or less. Note that the shape of the bottom portion 111 is not limited to a disc shape, but may also be a rectangular plate shape or a polygonal plate shape, etc. The side wall portion 112 extends upward from the periphery of the bottom portion 111. The height H1 of the case 110, from the outer bottom surface of the bottom portion 111 located on the outer surface of the case 110 to the upper end of the side wall portion 112, is, for example, 9.0 mm. The case 110 is made of a conductive material. In this embodiment, the case 110 is made of, for example, an aluminum alloy. However, the material constituting the case 110 is not limited to a conductive material, but may also be an insulating material. The case 110 is formed, for example, by forging. The piezoelectric element 120 includes a piezoelectric body made of, for example, ceramics. In this embodiment, the piezoelectric body included in the piezoelectric element 120 is made of PZT (lead zirconate titanate) ceramics. However, the piezoelectric body included in the piezoelectric element 120 is not limited to PZT ceramics, but may be other piezoelectric materials. A unimorph type piezoelectric vibrator is constructed by attaching a piezoelectric element 120 to the bottom portion 111. The piezoelectric element 120 may also be a bimorph type piezoelectric vibr