Ultrasonic transducer and method for manufacturing same

Abstract

The flexible printed circuit board (140) includes a first surface portion (141), a second surface portion (142), and a third surface portion (143). The first surface portion (141) has a first electrode (145) electrically connected to the piezoelectric element (120), and extends while being in contact with a first main surface (121) of the piezoelectric element (120). The second surface part (142) is bent from the edge of the first surface part (141) close to the side wall part (112) and extends along the side wall part (112) of the housing (110). The third surface portion (143) has a second electrode (146) electrically connected to the first end portion (131) of the terminal member (130), is bent in an S shape from the upper end of the second surface portion (142), and faces the first surface portion (141) with an interval therebetween. At least parts of the first surface part (141) and the second surface part (142), which are close to the first surface part (141), are embedded in the first filling member (150).

Description

Technical Field

[0001] The invention relates to an ultrasonic transducer and a method for manufacturing the same. Background Art

[0002] As a prior art document that discloses the structure of an ultrasonic sensor, there is International Publication No. 2013 / 051525 (Patent Document 1). The ultrasonic sensor described in Patent Document 1 includes a housing, a piezoelectric element, a pin terminal, a strip-shaped flexible substrate, and a vibration damper. The housing has a bottom plate and a side wall. The piezoelectric element is arranged on the bottom plate in the housing. The top end of one side of the pin terminal is arranged in the opening of the housing, and the top end of the other side is arranged outside the housing. The flexible substrate has a first end connected to the top end of one side of the pin terminal and a second end connected to the piezoelectric element. The vibration damper seals the top end of one side of the pin terminal and the flexible substrate in the housing. Prior art literature Patent Literature

[0003] Patent Document 1: International Publication No. 2013 / 051525 Summary of the invention Problems to be solved by the invention

[0004] In the ultrasonic sensor described in Patent Document 1, a portion of the flexible printed substrate close to the piezoelectric element is arranged directly above the piezoelectric element. In this case, this portion of the flexible printed substrate may hinder the absorption of ultrasonic vibration oscillating from the piezoelectric element by the filler filled in the housing. Therefore, there is room for improving the acoustic characteristics of the ultrasonic sensor by allowing the filler to fully absorb the ultrasonic vibration.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an ultrasonic transducer and a method for manufacturing the same, in which the acoustic characteristics are improved by allowing a filler to fully absorb ultrasonic vibrations. Technical means to solve problems

[0006] The ultrasonic transducer according to the present invention comprises a bottomed cylindrical shell, a piezoelectric element, a terminal component, a strip-shaped flexible printed substrate, a first filler, and a second filler. The shell has a bottom and a side wall. The piezoelectric element has a first main surface and a second main surface, and the second main surface is attached to the bottom on the inner side of the shell. The terminal component has a first end portion arranged on the inner side of the shell and a second end portion arranged on the outer side of the shell. The flexible printed substrate electrically connects the piezoelectric element to the first end portion of the terminal component. The first filler is filled in a manner of filling the bottom side in the shell. The second filler is filled in a manner of filling the first filler in the shell. The flexible printed substrate includes a first face portion, a second face portion, and a third face portion. The first face portion has a first electrode electrically connected to the piezoelectric element, and extends while contacting the first main surface of the piezoelectric element. The second face portion is bent and erected from the edge of the first face portion close to the side wall portion, and extends along the side wall portion of the shell. The third face portion has a second electrode electrically connected to the first end portion of the terminal component, is bent in an S-shape from the upper end of the second face portion, and faces the first face portion with a gap. At least the portions of the first surface and the second surface close to the first surface are buried in the first filling member. Effects of the Invention

[0007] According to the present invention, the acoustic characteristics of the ultrasonic transducer can be improved by allowing the filler to sufficiently absorb ultrasonic vibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a longitudinal sectional view of the ultrasonic transducer according to the first embodiment of the present invention. Figure 2 This is a flowchart showing the method for manufacturing the ultrasonic transducer according to the first embodiment of the present invention. Figure 3 This is a cross-sectional view showing a state in which a piezoelectric element included in the ultrasonic transducer according to the first embodiment of the present invention is connected to a flexible printed circuit board. Figure 4 This is a longitudinal sectional view showing a state in which a piezoelectric element included in the ultrasonic transducer according to the first embodiment of the present invention is attached to the bottom of a housing. Figure 5 This is a longitudinal sectional view showing a state in which the first filling material included in the ultrasonic transducer according to the first embodiment of the present invention is filled in the interior of the housing. Figure 6 This is a longitudinal sectional view showing a state in which a terminal member included in the ultrasonic transducer according to the first embodiment of the present invention is connected to a flexible printed circuit board. Figure 7 This is a longitudinal sectional view showing a state in which the first end portion of the terminal member is arranged inside the housing by bending the flexible printed circuit board included in the ultrasonic transducer according to the first embodiment of the present invention. Figure 8 It is a longitudinal sectional view of an ultrasonic transducer according to Embodiment 2 of the present invention. DETAILED DESCRIPTION

[0009] Hereinafter, an ultrasonic transducer according to each embodiment of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same or corresponding parts in the drawings are denoted by the same reference numerals, and their description will not be repeated.

[0010] In addition, in the drawings, a direction along the bottom of the housing is referred to as a DR1 direction, and a height direction of the housing is referred to as a DR2 direction.

[0011] (Implementation Method 1) Figure 1 is a longitudinal sectional view of an ultrasonic transducer according to Embodiment 1 of the present invention. Figure 1 As shown, the ultrasonic transducer 100 according to the present embodiment is, for example, an ultrasonic sensor.

[0012] like Figure 1 As shown, the ultrasonic transducer 100 includes a bottomed cylindrical housing 110 , a piezoelectric element 120 , a terminal member 130 , a belt-shaped flexible printed substrate 140 , a first filler 150 , and a second filler 160 .

[0013] The housing 110 has a bottom 111 and a side wall portion 112. When viewed from the DR2 direction, the bottom 111 of the present embodiment has a disk-like shape. The diameter of the bottom 111 is, for example, greater than 14.0 mm and less than 15.5 mm. In addition, the shape of the bottom 111 is not limited to a disk-like shape, and may also be a rectangular plate or a polygonal plate, etc.

[0014] The side wall portion 112 extends upward from the peripheral edge of the bottom portion 111. The height H1 of the housing 110 from the outer bottom surface of the bottom portion 111 located on the outer surface of the housing 110 to the upper end of the side wall portion 112 is, for example, 9.0 mm.

[0015] The housing 110 is made of a conductive material. In the present embodiment, the housing 110 is made of, for example, an aluminum alloy. However, the material constituting the housing 110 is not limited to a conductive material, and may be an insulating material. The housing 110 is formed, for example, by forging.

[0016] The piezoelectric element 120 includes a piezoelectric body made of, for example, ceramics. In the present 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, and may be other piezoelectric materials.

[0017] A unimorph piezoelectric vibrator is formed by attaching the piezoelectric element 120 to the bottom portion 111. Alternatively, the piezoelectric element 120 may be a bimorph piezoelectric vibrator or a multimorph piezoelectric vibrator.

[0018] A pair of electrodes (not shown) are provided on the piezoelectric element 120. When a voltage is applied to the pair of electrodes, the piezoelectric element 120 is driven to vibrate. When the piezoelectric element 120 vibrates, the bottom 111 vibrates.

[0019] When the bottom 111 of the housing 110 vibrates by receiving ultrasonic waves from the outside, the piezoelectric element 120 also vibrates with the vibration. Since electric charges are generated with the vibration of the piezoelectric element 120, the ultrasonic waves are converted into electrical signals by the piezoelectric element 120. The electrical signals are transmitted to the outside through a pair of electrodes.

[0020] like Figure 1 As shown, in the ultrasonic transducer 100 according to the present embodiment, the piezoelectric element 120 is arranged at a substantially central position of the housing 110 in the DR1 direction.

[0021] The piezoelectric element 120 includes a first main surface 121 and a second main surface 122. The first main surface 121 and the second main surface 122 are opposite to each other. The second main surface 122 is attached to the bottom 111 inside the housing 110. In this embodiment, the piezoelectric element 120 is bonded to the bottom 111 by epoxy resin.

[0022] In the DR1 direction, the ratio of the width of the internal space of the housing 110 to the width of the piezoelectric element 120 is 1.1 or more. This ratio allows the piezoelectric element 120 to be attached to the bottom 111 of the housing 110 without overloading the flexible printed circuit board 140 described later.

[0023] The terminal member 130 in this embodiment is a pin terminal and includes a first end portion 131 , a second end portion 132 , and a support member 133 .

[0024] The first end portion 131 is disposed inside the housing 110. The second end portion 132 is disposed outside the housing 110. The support member 133 supports the first end portion 131 and the second end portion 132. The first end portion 131, the second end portion 132, and the support member 133 are respectively made of a conductive material.

[0025] The flexible printed substrate 140 electrically connects the piezoelectric element 120 and the first end portion 131 of the terminal member 130. The flexible printed substrate 140 is provided with electric wiring for applying a voltage to the piezoelectric element 120, a signal line for transmitting an electric signal generated in the piezoelectric element 120, and the like.

[0026] The flexible printed circuit board 140 includes a first surface portion 141 , a second surface portion 142 , and a third surface portion 143 .

[0027] The first surface portion 141 extends while being in contact with the first principal surface 121 of the piezoelectric element 120. The first surface portion 141 extends along the DR1 direction.

[0028] The first surface portion 141 has a first electrode 145 electrically connected to the piezoelectric element 120. The first electrode 145 is connected to the first principal surface 121 of the piezoelectric element 120 by, for example, welding.

[0029] The second surface portion 142 is bent and raised from the edge of the first surface portion 141 close to the side wall portion 112, and extends along the side wall portion 112 of the housing 110. In the present embodiment, the second surface portion 142 is in direct contact with the side wall portion 112. In addition, the second surface portion 142 may extend along the side wall portion 112 while leaving a gap relative to the side wall portion 112. In addition, the second surface portion 142 in the present embodiment is mainly composed of a straight line shape, but may be bent within a range in which the piezoelectric element 120 and the second surface portion 142 are not parallel to each other in the DR2 direction.

[0030] In this embodiment, the flexible printed substrate 140 near the piezoelectric element 120 has a portion fixed in a straight line in the housing 110, so it is easy to position the flexible printed substrate 140. As a result, the fluctuation of the position of the first filler 150 that fills a part of the flexible printed substrate 140 described later is suppressed. As a result, the fluctuation of the sound absorption characteristics of the first filler 150 that absorbs the ultrasonic vibration oscillating from the piezoelectric element 120 can be suppressed, and therefore, the fluctuation of the acoustic characteristics of the ultrasonic transducer 100 with respect to the ultrasonic vibration can be suppressed.

[0031] The curvature R of the second surface 142 of the flexible printed substrate 140 located at the boundary with the edge of the first surface 141 is 0.8 (1 / mm) or more and 2.9 (1 / mm) or less. Thus, it is possible to suppress overload on the boundary between the first surface 141 and the second surface 142, and to allow the second surface 142 to directly contact the side wall 112 and to follow the side wall 112.

[0032] The third surface portion 143 is bent in an S-shape from the upper end of the second surface portion 142 and faces the first surface portion 141 with a gap therebetween. The third surface portion 143 is bent in an S-shape along the DR1 direction. In addition, the third surface portion 143 is not limited to being bent in an S-shape, but may be straight along the DR1 direction, or may be a meandering shape, etc.

[0033] The third surface portion 143 has a second electrode 146 electrically connected to the first end portion 131 of the terminal member 130. The second electrode 146 is connected to the first end portion 131 of the terminal member 130 by welding, for example.

[0034] The first electrode 145 and the second electrode 146 are disposed on either the front surface or the back surface of the flexible printed substrate 140. In this embodiment, when the surface of the flexible printed substrate 140 connected to the piezoelectric element 120 and the first end 131 of the terminal member 130 is set as the front surface, the first electrode 145 and the second electrode 146 are disposed on the front surface.

[0035] When the first electrode 145 and the second electrode 146 are provided on the flexible printed substrate 140, in the case where the first electrode 145 and the second electrode 146 are respectively arranged on the front surface and the back surface of the flexible printed substrate 140, the manufacturing process of providing the first electrode 145 and the second electrode 146 on the flexible printed substrate 140 becomes a plurality of processes. Therefore, the manufacturing process becomes complicated and the manufacturing cost increases. On the other hand, in the case where the first electrode 145 and the second electrode 146 are arranged on either the front surface or the back surface of the flexible printed substrate 140, the manufacturing process of providing the first electrode 145 and the second electrode 146 on the flexible printed substrate 140 can be made into a single process, so the flexible printed substrate 140 can be manufactured at a low cost.

[0036] The first filler 150 is filled in a manner that fills the bottom 111 side of the housing 110. The piezoelectric element 120 and a portion of the flexible printed substrate 140 are buried in the first filler 150. Specifically, in the flexible printed substrate 140, at least a portion of the first surface 141 and the second surface 142 close to the first surface 141 is buried in the first filler 150.

[0037] The first filler 150 is made of foamed silicone resin and is formed by curing liquid silicone resin.

[0038] The first filler 150 has a height H2 from the outer bottom surface of the bottom 111 located on the outer surface of the housing 110 to the upper end of the first filler 150. The ratio of the height H2 of the first filler 150 to the height H1 of the housing 110 in the height direction (DR2 direction) orthogonal to the bottom 111 is 0.3 times or more and 0.7 times or less. Thus, the space for the first end 131 of the terminal member 130 to be arranged inside the housing 110 can be ensured, and the reduction in the sound absorption characteristics of the ultrasonic vibration of the first filler 150 can be suppressed.

[0039] The second filler 160 is filled so as to fill the first filler 150 in the housing 110. The second filler 160 is made of silicone resin. Alternatively, the second filler 160 may be made of a resin material such as polyurethane resin.

[0040] Hereinafter, a method for manufacturing the ultrasonic transducer 100 according to the first embodiment of the present invention will be described.

[0041] Figure 2 This is a flowchart showing the method for manufacturing the ultrasonic transducer according to the first embodiment of the present invention. Figure 3 This is a cross-sectional view showing a state in which a piezoelectric element included in the ultrasonic transducer according to the first embodiment of the present invention is connected to a flexible printed circuit board. Figure 4 This is a longitudinal sectional view showing a state in which a piezoelectric element included in the ultrasonic transducer according to the first embodiment of the present invention is attached to the bottom of a housing. Figure 5 This is a longitudinal sectional view showing a state in which the first filling material included in the ultrasonic transducer according to the first embodiment of the present invention is filled in the interior of the housing. Figure 6 This is a longitudinal sectional view showing a state in which a terminal member included in the ultrasonic transducer according to the first embodiment of the present invention is connected to a flexible printed circuit board. Figure 7 This is a longitudinal sectional view showing a state in which the first end portion of the terminal member is arranged inside the housing by bending the flexible printed circuit board included in the ultrasonic transducer according to the first embodiment of the present invention.

[0042] like Figure 2 and Figure 3 As shown in FIG. 1 , as a method for manufacturing the ultrasonic transducer 100 , first, the first electrode 145 of the flexible printed substrate 140 is connected to the first principal surface 121 of the piezoelectric element 120 (step S1 ).

[0043] Then, if Figure 2 and Figure 4 As shown, the second main surface 122 of the piezoelectric element 120 connected with the flexible printed substrate 140 is attached to the bottom 111, and the second electrode 146 is arranged outside the housing 110 while the flexible printed substrate 140 is brought into contact with the side wall 112 and bent (S2 process). Thus, the first surface 141 is formed in the flexible printed substrate 140.

[0044] Since the flexible printed substrate 140 is bent while being in contact with the side wall portion 112, the side wall portion 112 can support the flexible printed substrate 140, and thus the fluctuation of the position of the second electrode 146 of the flexible printed substrate 140 is suppressed. Specifically, the position accuracy of the second electrode 146 can be made less than ±0.2 mm relative to the design position. As a result, when the flexible printed substrate 140 and the terminal component 130 described later are connected, the fluctuation of the connection position between them is suppressed, and it is easy to realize the automation of the connection between the flexible printed substrate 140 and the terminal component 130 by automated equipment.

[0045] Then, if Figure 2 and Figure 5 As shown, the first filler 150 is filled so as to fill the bottom 111 side in the case 110, thereby fixing a part of the flexible printed circuit board 140 (step S3).

[0046] The first filler 150 can be formed by casting. In casting, liquid silicone resin is applied to the piezoelectric element 120 and the flexible printed substrate 140 in the housing 110, and then the liquid silicone resin is cured. As a result, the first filler 150 can be placed in close contact with the piezoelectric element 120 and the flexible printed substrate 140 regardless of their shapes.

[0047] Then, if Figure 2 and Figure 6 As shown, the second electrode 146 of the flexible printed substrate 140 is connected to the first end 131 of the terminal member 130 on the outside of the housing 110 (S4 process). By fixing a part of the flexible printed substrate 140 by the first filler 150, the deformation of the entire flexible printed substrate 140 is suppressed. In addition, when the surface of the flexible printed substrate 140 connected to the piezoelectric element 120 and the first end 131 of the terminal member 130 is set as the front surface, the first end 131 may be connected to the back surface of the flexible printed substrate 140.

[0048] When the second electrode 146 is connected to the first end 131, a portion of the flexible printed substrate 140 extends linearly along the side wall portion 112 to the outside of the housing 110, so that no obstacles are arranged around the second electrode 146 and space is ensured. When the second electrode 146 and the first end 131 are connected by welding using an automated device, interference between the terminal member 130 and the flexible printed substrate 140 and the components of the automated device is suppressed, and the connection between the second electrode 146 and the first end 131 can be automated.

[0049] Then, if Figure 2 and Figure 7As shown, while the second end 132 of the terminal component 130 is located on the outside of the shell 110, the first end 131 of the terminal component 130 connected to the flexible printed substrate 140 is arranged on the inside of the shell 110 and the portion of the flexible printed substrate 140 exposed from the first filler 150 is bent (S5 process).

[0050] A portion of the flexible printed substrate 140 is fixed by filling the first filler 150, and the portion of the flexible printed substrate 140 exposed from the first filler 150 is bent while the portion of the flexible printed substrate 140 buried in the first filler 150 maintains its shape. Thus, the second surface portion 142 and the third surface portion 143 are formed in the flexible printed substrate 140.

[0051] Then, if Figure 1 and Figure 2 As shown, the second filler 160 is filled in the casing 110 so as to fill the first filler 150 and the bent portion of the flexible printed circuit board 140 exposed from the first filler 150 (step S6 ). The ultrasonic transducer 100 can be manufactured through the above steps.

[0052] (Experimental example) Here, a first experimental example is described in which the relationship between the ratio of the height H2 of the first filler 150 to the height H1 of the housing 110 and the quality judgment of the arrangement state when the piezoelectric element 120 and the flexible printed substrate 140 are arranged in the housing 110 is verified. As experimental conditions, when the ratio of the height H2 of the first filler 150 to the height H1 of the housing 110 is changed, it is verified whether the piezoelectric element 120 and the flexible printed substrate 140 can be arranged in the housing 110 without any problem.

[0053] Table 1 summarizes the relationship between the ratio of the height H2 of the first filler 150 to the height H1 of the housing 110 and the quality judgment of the arrangement state when the piezoelectric element 120 and the flexible printed circuit board 140 are arranged in the housing 110 based on the results of the first experimental example.

[0054] [Table 1]

[0055] As shown in Table 1, when the ratio is 0.3 or more and 0.7 or less, the piezoelectric element 120 and the flexible printed circuit board 140 can be arranged inside the housing 110 without any problem.

[0056] On the other hand, when the ratio is 0.2, although a part of the flexible printed circuit board 140 can be fixed by the first filler 150, the sound absorption property of the first filler 150 is reduced and the reverberation vibration becomes longer. Therefore, the close-range detection performance when the ultrasonic transducer 100 is used as an ultrasonic sensor is deteriorated.

[0057] In addition, when the ratio is 0.8, when the flexible printed substrate 140 is bent and arranged in the housing 110, there is insufficient space in the housing 110, so the flexible printed substrate 140 cannot be entirely accommodated in the housing 110. In addition, the ratio can be measured by observing the ultrasonic transducer cut in a longitudinal section using an optical microscope or the like.

[0058] Next, a second experimental example is described in which the relationship between the curvature R of the boundary between the first surface 141 and the second surface 142 of the flexible printed substrate 140 and the quality judgment of the arrangement state of the flexible printed substrate 140 is verified. As experimental conditions, when the curvature R is changed, it is verified whether the flexible printed substrate 140 can be arranged in the housing 110 without any problem.

[0059] Table 2 summarizes the relationship between the curvature R of the boundary between the first surface portion 141 and the second surface portion 142 of the flexible printed substrate 140 and the quality determination of the arrangement state of the flexible printed substrate 140 based on the results of the second experimental example.

[0060] [Table 2] condition 1 2 3 4 5 Curvature (1 / mm) 5.0 2.9 1.1 0.8 0.7 Configuration status of flexible printed circuit board not good good good good not good

[0061] As shown in Table 2, when the curvature R is greater than or equal to 0.8 (1 / mm) and less than or equal to 2.9 (1 / mm), the flexible printed circuit board 140 can be arranged inside the housing 110 without any problem.

[0062] On the other hand, when the curvature R is 0.7, the flexible printed circuit board 140 is tilted in the housing 110, and the flexible printed circuit board 140 cannot be arranged along the side wall portion 112. Therefore, the flexible printed circuit board 140 cannot be positioned in the housing 110, and the connection between the second electrode 146 and the first end portion 131 cannot be automated.

[0063] In addition, when the curvature R is 5.0, stress concentration occurs on the piezoelectric element 120 from the first surface portion 141 formed by bending the flexible printed substrate 140. As a result, poor conduction occurs between the piezoelectric element 120 and the flexible printed substrate 140. The curvature R can be measured by observing the ultrasonic transducer cut in a longitudinal section using an optical microscope or the like, for example.

[0064] In the ultrasonic transducer 100 according to the first embodiment of the present invention, the second surface 142 of the flexible printed substrate 140 is bent and raised from the edge of the first surface 141 close to the side wall 112, and extends along the side wall 112 of the housing 110, thereby increasing the arrangement ratio of the first filler 150 directly above the piezoelectric element 120, so that the ultrasonic vibration oscillating from the piezoelectric element 120 can be absorbed by the first filler 150. As a result, the sound absorbing characteristics of the first filler 150 can be fully utilized, so that the acoustic characteristics of the ultrasonic transducer 100 can be improved.

[0065] In the ultrasonic transducer 100 according to the first embodiment of the present invention, the second surface portion 142 is fixed to the first filler 150 while extending along the side wall portion 112, so that the position of a portion of the flexible printed substrate 140 close to the piezoelectric element 120 can be suppressed from fluctuating. Therefore, the position of the first filler 150 covering the portion of the flexible printed substrate 140 close to the piezoelectric element 120 can be suppressed from fluctuating. As a result, the sound absorption characteristics of the first filler 150 can be suppressed from fluctuating.

[0066] In the ultrasonic transducer 100 according to the first embodiment of the present invention, the second surface portion 142 is in direct contact with the side wall portion 112, so that the flexible printed substrate 140 can be easily positioned in the housing 110, and thus the fluctuation of the sound absorbing characteristics of the first filler 150 can be suppressed. Therefore, the fluctuation of the position of the first filler 150 covering the portion of the flexible printed substrate 140 close to the piezoelectric element 120 can be suppressed. As a result, the fluctuation of the sound absorbing characteristics of the first filler 150 can be suppressed.

[0067] In the ultrasonic transducer 100 involved in embodiment 1 of the present invention, by configuring the first electrode 145 and the second electrode 146 on either the front surface or the back surface of the flexible printed substrate 140, the first electrode 145 and the second electrode 146 can be formed on the flexible printed substrate 140 through the same manufacturing process, thereby simplifying the manufacturing process of the flexible printed substrate 140 and manufacturing the flexible printed substrate 140 at a low cost.

[0068] In the ultrasonic transducer 100 involved in embodiment 1 of the present invention, by making the ratio of the height H2 of the first filler 150 in the height direction (DR2 direction) orthogonal to the bottom 111 to the height H1 of the shell 110 be greater than 0.3 times and less than 0.7 times, the first end portion 131 can be accommodated in the shell 110 while maintaining the sound absorption characteristics of the first filler 150.

[0069] In the ultrasonic transducer 100 according to the first embodiment of the present invention, by making the curvature R of the second surface 142 of the flexible printed substrate 140 located at the boundary with the edge of the first surface 141 greater than or equal to 0.8 (1 / mm) and less than or equal to 2.9 (1 / mm), it is possible to form a curvature required for the flexible printed substrate 140 to stand upright in the housing 110 while suppressing an overload applied when the flexible printed substrate 140 is bent.

[0070] In the method for manufacturing the ultrasonic transducer 100 according to the first embodiment of the present invention, a portion of the flexible printed substrate 140 close to the piezoelectric element 120 is fixed by the first filler 150 while extending along the side wall portion 112, and the second electrode 146 is arranged outside the housing 110, so that the second electrode 146 and the first end portion 131 can be connected while a space is ensured around the second electrode 146. Thus, it is possible to suppress the terminal member 130 and the flexible printed substrate 140 from interfering with the components of the automation equipment, so that the connection between the second electrode 146 and the first end portion 131 can be automated. Furthermore, by automating the connection between the terminal member 130 and the flexible printed substrate 140, the ultrasonic transducer 100 can be efficiently manufactured.

[0071] (Implementation Method 2) Hereinafter, an ultrasonic transducer according to Embodiment 2 of the present invention will be described with reference to the accompanying drawings. The configuration of the terminal member of the ultrasonic transducer according to Embodiment 2 of the present invention is different from that of the ultrasonic transducer 100 according to Embodiment 1 of the present invention, and therefore the same configuration as that of the ultrasonic transducer 100 according to Embodiment 1 of the present invention will not be described repeatedly.

[0072] Figure 8 2 is a longitudinal sectional view of an ultrasonic transducer according to Embodiment 2 of the present invention. Figure 8 As shown, the ultrasonic transducer 200 according to the second embodiment of the present invention includes a bottomed cylindrical housing 110, a piezoelectric element 120, a terminal member 230, a strip-shaped flexible printed substrate 240, a first filler 150, and a second filler 160. The terminal member 230 in this embodiment is a lead terminal.

[0073] The flexible printed circuit board 240 includes a first surface portion 241 , a second surface portion 242 , and a third surface portion 243 .

[0074] The third surface portion 243 has a second electrode 246 electrically connected to the terminal member 230. The second electrode 246 is connected to the terminal member 230 by welding, for example.

[0075] In the ultrasonic transducer 200 according to the second embodiment of the present invention, the second surface 242 of the flexible printed substrate 240 is bent and raised from the edge of the first surface 241 close to the side wall 112 and extends along the side wall 112 of the housing 110, so that the arrangement ratio of the first filler 150 directly above the piezoelectric element 120 can be increased, and thus the ultrasonic vibration oscillating from the piezoelectric element 120 can be absorbed by the first filler 150. As a result, the sound absorbing characteristics of the first filler 150 can be fully utilized.

[0076] In the ultrasonic transducer 200 according to the second embodiment of the present invention, since the terminal member 230 is a lead terminal, the degree of freedom in bending the third surface portion 243 of the flexible printed substrate 240 can be increased compared to the case where the terminal member is a pin terminal.

[0077] [Note] <1> An ultrasonic transducer comprising: A bottomed cylindrical housing having a bottom and a side wall; A piezoelectric element having a first main surface and a second main surface, wherein the second main surface is attached to the bottom inside the housing; a terminal member having a first end portion disposed inside the housing and a second end portion disposed outside the housing; a strip-shaped flexible printed substrate electrically connecting the piezoelectric element and the first end portion of the terminal member; A first filling member that is filled in a manner of filling up the bottom side of the housing; and a second filling member, which is filled in the shell in a manner of burying the first filling member, The flexible printed substrate comprises: a first face portion having a first electrode electrically connected to the piezoelectric element and extending while being in contact with the first main surface of the piezoelectric element; a second surface portion, which is bent and erected from an edge of the first surface portion close to the side wall portion and extends along the side wall portion of the housing; and The third face portion has a second electrode electrically connected to the first end portion of the terminal member, is bent in an S-shape from the upper end of the second face portion, and faces the first face portion with a gap therebetween. At least portions of the first surface and the second surface close to the first surface are buried in the first filling member.

[0078] <2> according to <1> The ultrasonic transducer of claim 1, wherein The second surface portion is in direct contact with the side wall portion.

[0079] <3> according to <1> or <2> The ultrasonic transducer of claim 1, wherein The first electrode and the second electrode are disposed on either a front surface or a back surface of the flexible printed substrate.

[0080] <4> according to <1> to <3> An ultrasonic transducer as claimed in any one of the claims , wherein: A ratio of a height of the first filler to a height of the housing in a height direction perpendicular to the bottom is not less than 0.3 times and not more than 0.7 times.

[0081] <5> according to <1> to <4> An ultrasonic transducer as claimed in any one of the claims , wherein: The curvature of the curve of the second surface portion of the flexible printed substrate located at a boundary with the edge of the first surface portion is 0.8 (1 / mm) or more and 2.9 (1 / mm) or less.

[0082] <6> A method for manufacturing an ultrasonic transducer, The ultrasonic transducer has: A piezoelectric element having a first main surface and a second main surface; A bottomed cylindrical housing having a bottom and a side wall; a terminal member having a first end and a second end; a strip-shaped flexible printed substrate having a first electrode and a second electrode for electrically connecting the piezoelectric element and the terminal member to each other; A first filling member filled in the shell; and A second filling member is filled in the shell, The manufacturing method comprises: a step of connecting the first electrode of the flexible printed substrate to the first main surface of the piezoelectric element; The step of attaching the second main surface of the piezoelectric element connected to the flexible printed substrate to the bottom portion, and placing the second electrode outside the housing while bending the flexible printed substrate in contact with the side wall portion; a step of filling the first filler so as to fill the bottom side of the housing to fix a portion of the flexible printed circuit board; A step of connecting the second electrode of the flexible printed circuit board to the first end of the terminal member outside the housing; The step of placing the first end of the terminal member connected with the flexible printed circuit board inside the housing and bending the portion of the flexible printed circuit board exposed from the first filler while the second end of the terminal member is located outside the housing; and A step of filling the second filling material in the housing so as to fill the first filling material and the bent portion of the flexible printed circuit board exposed from the first filling material.

[0083] In the description of the above embodiments, combinable configurations may be combined with each other.

[0084] The embodiments disclosed this time should be considered as illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims. Description of Reference Numerals

[0085] 100, 200 ultrasonic transducer, 110 housing, 111 bottom, 112 side wall, 120 piezoelectric element, 121 first main surface, 122 second main surface, 130, 230 terminal component, 131 first end, 132 second end, 133 supporting component, 140, 240 flexible printed substrate, 141, 241 first face portion, 142, 242 second face portion, 143, 243 third face portion, 145 first electrode, 146, 246 second electrode, 150 first filler, 160 second filler, H1, H2 height, R curvature.

Claims

1. An ultrasonic transducer comprising: A bottomed cylindrical housing having a bottom and a side wall; A piezoelectric element having a first main surface and a second main surface, wherein the second main surface is attached to the bottom inside the housing; a terminal member having a first end portion disposed inside the housing and a second end portion disposed outside the housing; a strip-shaped flexible printed substrate that electrically connects the piezoelectric element and the first end portion of the terminal member; A first filling member is filled in a manner of filling the bottom side of the housing; as well as a second filling member, which is filled in the shell in a manner of burying the first filling member, The flexible printed substrate comprises: a first face portion having a first electrode electrically connected to the piezoelectric element and extending while being in contact with the first main surface of the piezoelectric element; A second surface portion, which is bent and erected from an edge of the first surface portion close to the side wall portion and extends along the side wall portion of the housing; as well as The third face portion has a second electrode electrically connected to the first end portion of the terminal member, is bent in an S-shape from the upper end of the second face portion, and faces the first face portion with a gap therebetween. At least portions of the first surface and the second surface close to the first surface are buried in the first filling member.

2. The ultrasonic transducer according to claim 1, in, The second surface portion is in direct contact with the side wall portion.

3. The ultrasonic transducer according to claim 1 or 2, in, The first electrode and the second electrode are disposed on either a front surface or a back surface of the flexible printed substrate.

4. The ultrasonic transducer according to any one of claims 1 to 3, in, A ratio of a height of the first filler to a height of the housing in a height direction perpendicular to the bottom is not less than 0.3 times and not more than 0.7 times.

5. The ultrasonic transducer according to any one of claims 1 to 4, in, The curvature of the curve of the second surface portion of the flexible printed substrate located at a boundary with the edge of the first surface portion is 0.8 (1 / mm) or more and 2.9 (1 / mm) or less.

6. A method for manufacturing an ultrasonic transducer, The ultrasonic transducer has: A piezoelectric element having a first main surface and a second main surface; A bottomed cylindrical housing having a bottom and a side wall; a terminal member having a first end and a second end; a strip-shaped flexible printed substrate having a first electrode and a second electrode for electrically connecting the piezoelectric element and the terminal member to each other; A first filling member filled in the shell; as well as A second filling member is filled in the shell, The manufacturing method comprises: a step of connecting the first electrode of the flexible printed substrate to the first main surface of the piezoelectric element; The step of attaching the second main surface of the piezoelectric element connected to the flexible printed substrate to the bottom portion, and placing the second electrode outside the housing while bending the flexible printed substrate in contact with the side wall portion; A step of filling the first filler so as to fill the bottom side of the housing to fix a portion of the flexible printed circuit board; A step of connecting the second electrode of the flexible printed circuit board to the first end of the terminal member outside the housing; The step of placing the first end of the terminal member connected with the flexible printed circuit board inside the housing and bending the portion of the flexible printed circuit board exposed from the first filler while the second end of the terminal member is located outside the housing; and A step of filling the second filling material in the housing so as to fill the first filling material and the bent portion of the flexible printed circuit board exposed from the first filling material.

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