JP2007049481A - Ultrasonic device and its assembling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic device for transmitting and/or receiving ultrasonic waves, and capable of being assembled with a simple configuration. <P>SOLUTION: The ultrasonic device for transmitting the ultrasonic waves comprises a piezo-electric element (112), a housing (111) for containing the piezo-electric element (112) so that one electrode (133) of the piezo-electric element (112) is electrically connected to its bottom surface where an engaging part (122) is formed, a first conductive wire material (113 and 115) connected to the other electrode (132) of the piezo-electric element (112), a second conductive wire material (116) used as ground potential, and connecting members (114, 211, and 311) connected to the second conductive wire material (116) and engaged to the engaging part (122) to connect the second conductive wire material (116) with the housing (111). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultrasonic device and an assembling method thereof, and more particularly to an ultrasonic device that transmits and / or receives ultrasonic waves and an assembling method thereof.

  A conventional ultrasonic sensor generates an ultrasonic wave and receives the generated ultrasonic wave. The ultrasonic sensor is used in, for example, a distance measuring system that measures a distance to an object. In the distance measuring system, the signal from the ultrasonic sensor is detected, the time from transmission of the ultrasonic wave to reception thereof is measured, and the distance from the measured time to the object is measured.

  FIG. 8 shows a configuration diagram of an example of a conventional ultrasonic sensor.

The ultrasonic sensor 1 mainly connects a case 11, a piezoelectric element 12 disposed in the case 11, a terminal plate 13 that pulls the piezoelectric element 12 out of the case 11, a terminal plate 13, and the piezoelectric element 12. It comprised from the wire 14 and the shock absorbing material 15 with which the case 11 was filled (refer patent document 1, 2).
JP-A-11-266498 Japanese Patent Laid-Open No. 10-257595

  However, in the ultrasonic sensor, the characteristics are determined by the density of the buffer material 15 filled in the case 11. For example, if the density of the buffer material 15 is high, the reverberation decreases but the sensitivity also decreases. Further, when the density of the buffer material 15 is set low, there is a problem that the sensitivity increases but the reverberation increases.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an ultrasonic apparatus that has low reverberation and high sensitivity.

  The present invention relates to an ultrasonic device that transmits and / or receives ultrasonic waves, a piezoelectric element (112), a foamed resin sheet (117) disposed on the piezoelectric element (112), and a foamed resin sheet. And a resin buffer portion (118) made of a resin having a higher density than the foamed resin sheet (117).

  The foamable resin sheet (117) and the resin buffer portion (118) are made of silicone resin.

  The resin buffer portion (118) is characterized in that it is cured after filling the foamable resin sheet (117).

  The foamable resin sheet (117) is preliminarily formed into a sheet shape, and is attached to the piezoelectric element (112) with a double-sided tape.

  In addition, the present invention provides a piezoelectric element (112), a foamed resin sheet (117) laminated and disposed on the piezoelectric element (112), and a foamed resin sheet (117) laminated on the foamed resin sheet (117). An ultrasonic device having a resin buffer portion (118) made of a resin having a higher density than the resin sheet (117), and a foamable resin sheet (117) is pasted on the piezoelectric element (112) And a step of encapsulating the resin cushioning material (118) on the foamable resin sheet (117) and curing it.

  In addition, the said reference code is a reference to the last, This does not limit a claim.

  According to the present invention, the foamed resin sheet (117) is provided by being laminated on the piezoelectric element (112), and the resin is laminated on the foamed resin sheet (117) and has a higher density than the foamed resin sheet (117). By providing the resin buffer part (118), the sensitivity can be improved by the foamed resin sheet (117), and the reverberation can be suppressed by the resin buffer part (118). Can be high.

〔overall structure〕
FIG. 1 is an exploded perspective view of an embodiment of the present invention, and FIG. 2 is a sectional view of the embodiment of the present invention.

  The ultrasonic generator 100 of the present embodiment is a transmission / reception type ultrasonic sensor that generates and outputs an ultrasonic wave to the outside, and receives a reflected wave from the outside, and includes a case 111, a piezoelectric element 112, and a litz wire 113. , Connecting member 114, lead wires 115 and 116, silicone sheet 117, filler 118, and epoxy adhesive 119.

[Case 111]
FIG. 3 shows a configuration diagram of the case 111. 3A is a plan view, FIG. 3B is a front view, FIG. 3C is an AA cross-sectional view, FIG. 3D is a side view, and FIG. 3E is a BB cross-sectional view. Indicates.

  The case 111 is formed of an aluminum material in a substantially cylindrical shape with a bottom by cutting or the like. A step portion 121 is formed on the inner periphery of the case 111. An engaging portion 122 is formed on the upper surface side of the stepped portion 121 and the surface on the arrow Z1 direction side. In this embodiment, the engaging portion 122 is formed in a boss shape.

A groove 123 and a notch 124 are formed on the side surface of the case 111.
Furthermore, a hole 125 is formed in the direction of the arrow Z2 in the cross section formed by the notch 124. The groove part 123 and the notch part 124 are used for positioning or the like when attached to the attachment target.

  Further, a groove 127 is formed on the bottom surface 126 of the case 111. By forming the groove 127, the adhesiveness with the piezoelectric element 112 can be improved.

  Note that the case 111 is subjected to electroless nickel plating after the respective parts are formed by cutting.

  Further, the case 111 has a thick side surface on the bottom 126 direction side where the piezoelectric element 112 is disposed and on the arrow Z2 direction side. Thus, directivity is given to the ultrasonic apparatus.

[Piezoelectric element 112]
FIG. 4 shows a configuration diagram of the piezoelectric element 112. 4A is a plan view, FIG. 4B is a front view, and FIG. 4C is a side view.

  The piezoelectric element 112 has a configuration in which electrodes 132 and 133 are formed on a ceramic substrate 131 formed in a circular shape. The electrode 132 is formed on the surface of the ceramic substrate 131 on the arrow Z1 direction side, and the electrode 133 is formed on the surface of the ceramic substrate 121 on the arrow Z2 direction side. The piezoelectric element 112 is housed in the case 118 so that the surface on the arrow Z2 direction side faces the bottom surface of the case 111. At this time, the surface of the piezoelectric element 112 on the arrow Z2 direction side is fixed to the bottom surface 126 of the case 111 with a thermosetting epoxy adhesive 119. At this time, the adhesion between the case 111 and the piezoelectric element 112 can be improved by the groove 127 formed on the bottom surface 126 of the case 111. As described above, the electrode 132 is electrically connected to the case 111 by the epoxy adhesive 119.

  One end of the litz wire 113 is connected to the electrode 133 of the piezoelectric element 112 by soldering or conductive paste. The other end of the litz wire 113 extends in the direction of the arrow Z1 through the cut portion 141 of the silicone sheet 117, and is connected to the lead wire 115 by soldering or conductive paste. The lead wire 116 is connected to the case 111 via the connection member 114.

[Connection member 114]
FIG. 5 shows a perspective view of the connecting member 114.

  The lead wire 116 is entangled with the through-hole 151 of the connection member 114 and soldered. The connecting member 114 is manufactured by punching a metal plate, and an engaging portion 152 is formed adjacent to the through hole 151. The engaging portion 152 has a structure in which a cross is cut. An engaging portion 122 formed in the case 111 is press-fitted into the engaging portion 152. When the protrusion-like engagement portion 122 is press-fitted into the engagement portion 152, the inner circumference of each wing portion 152a constituting the engagement portion 152 is displaced in the arrow Z1 direction side. As a result, the edge portion on the inner peripheral side of the wing portion 152 a bites into the engaging portion 122. Therefore, the connection member 114 can be prevented from coming off from the engagement portion 122 in the direction of the arrow Z1, and the connection member 114 can be reliably held in the case 111.

At this time, if necessary, the connecting member 114 may be soldered to the case 111. Since the case 111 is subjected to electroless nickel plating, the solderability is good due to normal eutectic soldering. Can be soldered. For this reason, soldering can be performed at a relatively low temperature. Therefore, it is possible to improve the assembling property. Note that the connection member 114 may be a terminal shape or a cylindrical shape.

  FIG. 6 is a perspective view of a modified example of the connection member 114. FIG. 6A is a perspective view of the first modification, and FIG. 6B is a perspective view of the second modification.

  A connection member 211 of the first modification shown in FIG. 6A is composed of a crimping part 221 and an engaging part 222.

  The crimping portion 221 is crimped to the connecting member 211 by bending the collar portion 231 in the directions of arrows A1 and A2 in a state where the lead wire 116 is mounted between the collar portions 231. Is fixed to and connected to the connection member 211.

  The engaging portion 222 is configured by a through hole 232 that is substantially the same as the outer diameter of the engaging portion 122. By press-fitting the engaging portion 122 into the through hole 232, the inner peripheral edge of the through hole 232 bites into the engaging portion 122, and the connecting member 211 is securely held by the engaging portion 122.

  A connection member 311 according to the first modification shown in FIG. 6B includes a cylindrical engagement portion 321 and a soldering portion 322.

  The cylindrical engaging portion 321 is formed by forming a conductive material into a bottomed cylindrical shape, and a projecting engaging portion 122 implanted in the case 111 is press-fitted on the inner peripheral side. The soldering portion 322 is provided on the outer surface, and the lead wire 116 is soldered.

  At this time, by soldering the connection members 211 and 311 to the case 111, the connection members 211 and 311 can be firmly held in the case 111, and the reliability can be improved.

  The silicone sheet 117 is made of a foamable silicone resin having a density of about 0.5, and a double-sided tape is affixed to the surface on the arrow Z2 direction side, and the surface on the arrow Z1 direction side of the piezoelectric element 112 by the double-sided tape. Glued to. At this time, the litz wire 113 soldered to the electrode 132 of the piezoelectric element 112 is drawn out to the surface on the arrow Z1 direction side of the silicone sheet 117 through the cut portion 141.

  The filler 118 is made of an ultraviolet curable silicone resin having a density of about 1.0 to 1.5, and is filled on the side of the silicone sheet 117 in the direction of arrow Z1. After filling the case 111, the filler 118 is cured by the ultraviolet ray irradiated from the opening surface of the case 111.

  The silicone resin is not limited to the ultraviolet curable type, but may be a thermosetting type, a two-component type, or a one-component condensed type.

  In this embodiment, the characteristics of the ultrasonic device 100 can be improved by laminating the silicone sheet 117 and the filler 118 made of silicone resins having different densities on the piezoelectric element 112.

  FIG. 7 is a diagram showing the characteristics of reverberation and sensitivity of the ultrasonic device according to the density of the silicone resin.

  The reverberation of the ultrasonic device 100 decreases as the density of the silicone resin filled in the case 111 increases as shown by the solid line in FIG. 7, and the sensitivity of the silicone resin filled in the case 111 as shown by the broken line in FIG. It tends to increase as the density increases.

  In this embodiment, a silicone sheet 117 having a low density and a filler 118 having a high density are combined and laid and filled in the case 111, whereby the sensitivity is improved by the silicone sheet 117 and reverberation is suppressed by the filler 118. Therefore, reverberation is small and sensitivity can be increased.

[Assembly process]
Next, the assembly process of the ultrasonic apparatus 100 of the present embodiment will be described.

  First, one end of the litz wire 113 is connected to the electrode 132 of the piezoelectric element 112 by soldering or conductive paste.

  Next, an epoxy-based adhesive 119 is applied to the electrode 131 of the piezoelectric element 112 and / or the bottom surface 126 of the case 111 to adhere the piezoelectric element 112 to the bottom surface 126 of the case 111.

  Next, a double-sided tape is applied to the surface of the silicone sheet 117 on the arrow Z2 direction side, and the other end of the litz wire 113 is extended to the surface of the silicone sheet 117 on the arrow Z1 direction side through the notch 141 of the silicone sheet 117. Then, the silicone sheet 117 is bonded to the piezoelectric element 112 with a double-sided tape.

  Thereby, since the silicone sheet 117 is firmly adhered to the piezoelectric element 112, the silicone sheet 117 can be prevented from being lifted, and stable characteristics of the piezoelectric element 112 can be obtained.

  Next, the other end of the litz wire 113 is soldered to the lead wire 115. Further, the lead wire 116 is tangled in the through hole 151 of the connection member 114 and then soldered to the connection member 114. Next, the engaging portion 152 of the connecting member 114 is engaged with the engaging portion 122 of the case 111. If necessary, the connection member 114 and the case 111 may be soldered so that the lead wire 116 is connected to the case 111.

  Next, the case 111 is filled with a filler 118, and the filler 118 is cured by irradiating ultraviolet rays from the opening surface of the case 111, for example.

  Thus, the filler 118 also serves to prevent the connection member 114 and the lead wires 115 and 116 from coming off.

  As described above, the ultrasonic apparatus 100 as shown in FIG. 2 is completed.

〔effect〕
According to the present embodiment, by connecting the lead wire 116 to the case 111 via the connecting member 114, soldering to the case 111 is unnecessary or easy. In addition, by performing electroless nickel plating on the case 111, the solderability between the connection member 114 and the case 111 can be improved, and soldering can be performed easily.

  Therefore, the assembling property of the ultrasonic device 100 can be improved.

  Furthermore, by laminating the silicone sheet 117 and the filler 118 made of silicone resins having different densities on the piezoelectric element 112, the reverberation of the ultrasonic device 100 can be reduced and the sensitivity can be enhanced.

[Others]
In this embodiment, the silicone sheet 117 is used as the portion of the silicone resin that is in close contact with the piezoelectric element 112. However, by curing the foamable silicone resin, a low-density silicone resin layer may be formed. Good.

  Further, by adjusting the thickness and density of the silicone sheet 117 according to the shape of the case 111 and the like, it becomes possible to easily optimize the characteristics of reverberation and sensitivity.

It is a disassembled perspective view of one Example of this invention. It is sectional drawing of one Example of this invention. 2 is a configuration diagram of a case 111. FIG. 2 is a configuration diagram of a piezoelectric element 112. FIG. FIG. 6 is a perspective view of a connection member 114. It is a perspective view of the modification of the connection member. It is a figure which shows the characteristic of the reverberation and sensitivity of an ultrasonic device according to the density of the silicone resin. It is a block diagram of an example of the conventional ultrasonic sensor.

Explanation of symbols

100, 200 Ultrasonic generator 111 Case, 112 Piezoelectric element, 113 Litz wire, 114 Connection member 115, 116 Lead wire, 117 Silicone sheet, 118 Filling material 119 Epoxy adhesive 121 Step part, 122 Engagement part, 123 Groove part , 124 Notch portion, 125 Hole portion 126 Bottom surface, 127 Groove 131 Ceramic substrate, 132, 133 Electrode 141 Cut portion 151 Through hole, 152 Engagement portion

Claims (7)

In an ultrasonic device for transmitting and / or receiving ultrasonic waves,
A piezoelectric element;
A resin sheet disposed on the piezoelectric element, and
An ultrasonic device comprising: a resin buffer portion formed by being laminated on the resin sheet. The ultrasonic device according to claim 1, wherein the resin sheet has a density lower than that of the resin buffer portion. The ultrasonic device according to claim 1, wherein the resin sheet and the resin buffer portion are made of a silicone resin. The ultrasonic device according to claim 1, wherein the resin buffer portion is hardened after filling the resin sheet. The resin sheet is previously formed into a sheet shape,
The ultrasonic device according to claim 1, wherein the ultrasonic device is attached to the piezoelectric element with a double-sided tape. A piezoelectric element; a foamed resin sheet disposed on the piezoelectric element; and a resin buffer portion disposed on the foamed resin sheet, the resin buffer portion including a resin having a higher density than the foamed resin sheet. An assembly method of an ultrasonic device having
Attaching the resin sheet on the piezoelectric element;
And a step of encapsulating the resin cushioning material on the resin sheet and curing the resin cushioning material. The method for assembling an ultrasonic device according to claim 6, wherein the resin sheet has a lower density than the resin cushioning material.

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