JP2018101924A - Ultrasonic transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve both miniaturization of an ultrasonic transducer and suppression of stress concentration on a connection pin of the ultrasonic transducer.SOLUTION: An ultrasonic transducer 10 includes: a piezoelectric element 13 arranged on one end side at the inside of a case 11; a substrate 15a arranged on the other end side at the inside of the case 11 and electrically connected to the piezoelectric element 13; a connection pin 15b fixed to the substrate 15a and having one end led to the outside of the case 11; and a resin 16 filled in the case 11. The substrate 15a is held by the resin 16 in a non-contact state with respect to the case 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ultrasonic transducer, and more particularly to an ultrasonic transducer in which a connection pin is led out of a case.

  Ultrasonic transducers that transmit ultrasonic waves and receive the reflected waves are used in various applications. For example, ultrasonic transducers are used for examination of a subject in the medical field and detection of an obstacle when a car is parked in a parking lot.

  This ultrasonic transducer inputs and outputs signals with an external circuit board. For connection to the circuit board, a configuration in which the lead wire derived from the ultrasonic transducer is connected to the circuit substrate (for example, see Patent Document 1), or a configuration in which the connection pin of the ultrasonic transducer is directly connected to the circuit board. (For example, see Patent Document 2) and the like are known.

JP 2006-204552 A JP 2006-279567 A

  In the configuration described in Patent Document 1, a lead wire is required between the ultrasonic vibrator and the circuit board, and the lead wire is interposed between the ultrasonic vibrator and the circuit board, so that downsizing is achieved. Is difficult. Further, the configuration described in Patent Document 2 does not require a lead wire and can be downsized.

  However, in general, the ultrasonic transducer is fixed on the substrate with a case or the like. At this time, if a positional deviation occurs due to a manufacturing error or an assembly error in the positional relationship between the ultrasonic transducer and the circuit board, When the connection pin of the ultrasonic transducer and the circuit board are connected in this misalignment state, stress is applied to the connection portion, and connection failure between the connection pin and the circuit board may occur. Further, stress may act between the connection pins of the ultrasonic vibrator and the circuit board due to vibration of the ultrasonic vibrator or external vibration (including impact).

  With the configuration described in Patent Document 1, even if a positional shift due to a manufacturing error or an assembly error occurs in the positional relationship between the ultrasonic transducer and the circuit board, the positional shift is caused by the lead wire of the ultrasonic transducer. Although the stress due to is absorbed, it is difficult to reduce the size as described above.

  Therefore, an object of the present invention is to provide an ultrasonic transducer that achieves both miniaturization of the ultrasonic transducer and suppression of stress concentration on the connection portion of the ultrasonic transducer.

  The ultrasonic transducer according to the present invention includes a cylindrical case, a piezoelectric element disposed at one end inside the case, and the other end within the case, and is electrically connected to the piezoelectric element. An ultrasonic vibrator comprising a substrate, a connection pin fixed to the substrate and having one end led out of the case, and a resin filled in the case, wherein the substrate comprises: The resin is held by the resin in a non-contact state with respect to the case.

  The resin includes a first resin filled around the piezoelectric element and a second resin filled around the substrate, and the elastic modulus of the first resin is the second resin. Smaller than the elastic modulus of the resin.

  The substrate is held by the case via an elastic member. Further, the elastic member is an annular silicone rubber.

  According to the present invention, it is possible to achieve both miniaturization of an ultrasonic transducer and suppression of stress concentration on a connection portion of the ultrasonic transducer. As a result, the application range of the ultrasonic vibrator can be expanded by downsizing, and the occurrence of poor connection between the connection pins of the ultrasonic vibrator and the circuit board can be suppressed.

It is a schematic sectional drawing of the ultrasonic transducer | vibrator which shows 1st Embodiment. It is a schematic sectional drawing of the ultrasonic transducer | vibrator which shows 2nd Embodiment. It is a schematic sectional drawing of the ultrasonic transducer | vibrator which shows 3rd Embodiment.

  A first embodiment will be described with reference to FIG. As shown in FIG. 1, the ultrasonic transducer 10 includes a cylindrical case 11 made of PBT resin (polybutylene terephthalate resin), a matching layer 12 fixed to one end of the case 11, and the inside of the case 11. A piezoelectric element 13 disposed facing the matching layer 12, a backing material 14 disposed adjacent to the piezoelectric element 13, and a pin header 15 disposed on the other end side of the case 11 inside the case 11; And a silicone resin 16 filled in the case 11.

  Electrodes (not shown) are formed on both surfaces of the piezoelectric element 13. These electrodes are connected to the pin header 15 by lead wires 17a and 17b. The pin header 15 includes a substrate 15a to which the lead wires 17a and 17b are connected, a plurality of connection pins 15b connected to the substrate 15a, and a fixing resin 15c that fixes the connection pins 15b to the substrate 15a.

  The connection pin 15b has a length leading out of the case 11, and is fixed to the circuit board KB to which the ultrasonic transducer 10 is attached by, for example, soldering. The circuit board KB is fixed to the circuit board fixing portion FPa.

  The case 11 is filled with the silicone resin 16 after the piezoelectric element 13, the backing material 14, and the pin header 15 are disposed. A silicone resin 16 that has elasticity even after curing is used. That is, the pin header 15 having elasticity that allows the silicone resin 16 to move even after the silicone resin 16 is cured is used. Further, when the silicone resin 16 is filled, the pin header 15 is held at a position separated from the inner peripheral surface of the case 11 using a jig or the like, and the silicone resin 16 is filled into the case 11. Then, after the silicone resin 16 is cured, the ultrasonic vibrator 10 is attached to the circuit board KB.

  When the ultrasonic transducer 10 is attached to the circuit board KB, if the positional relationship between the connection pin 15b of the pin header 15 and the circuit board KB is displaced due to a manufacturing error, an assembly error, or the like, When the ultrasonic transducer 10 is vibrated through the ultrasonic transducer fixing portion FPb that fixes the ultrasonic transducer 10 and a positional shift occurs, or the ultrasonic transducer 10 vibrates and the positional shift occurs. Even if it occurs, since the pin header 15 can move inside the case 11, these positional shifts can be absorbed and stress concentration on the connecting portion is suppressed.

  For this reason, it is possible to suppress the occurrence of connection failure between the connection pin 15b and the circuit board KB. Further, since the ultrasonic transducer 10 is directly attached to the circuit board KB, a lead wire between the ultrasonic transducer 10 and the circuit board KB can be eliminated, and the number of components can be reduced and the size can be reduced. Can be planned.

  The lengths of the lead wires 17a and 17b between the piezoelectric element 13 and the pin header 15 are long enough to prevent tension from acting on the lead wires 17a and 17b even if the pin header 15 moves. Preferably.

  Next, a second embodiment will be described with reference to FIG. In each embodiment described below, the same components as those described in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 2, in the ultrasonic vibrator 20, two types of silicone resins, a first silicone resin 18 and a second silicone resin 19, are used as the silicone resin filled in the case 11.

  Inside the case 11, the first silicone resin 18 is filled around the piezoelectric element 13 and the backing material 14. In the case 11, the second silicone resin 19 is filled around the substrate 15 a of the pin header 15.

  The elastic modulus of the first silicone resin 18 is smaller than the elastic modulus of the second silicone resin 19. That is, after the filling of the first silicone resin 18 and the second silicone resin 19, the first silicone resin 18 around the piezoelectric element 13 and the backing material 14 is the second around the substrate 15 a of the pin header 15. The silicone resin 19 is softer.

  As described above, the first silicone resin 18 around the piezoelectric element 13 and the backing material 14 and the second silicone resin 19 around the substrate 15a of the pin header 15 have different elastic moduli. Inside, the piezoelectric element 13 and the substrate 15a of the pin header 15 can be optimally held.

  That is, when vibration is applied to the ultrasonic transducer 10 from the outside via the ultrasonic transducer fixing portion FPb that fixes the ultrasonic transducer 10, the piezoelectric element 13 and the backing are formed by the first silicone resin 18. Transmission of vibration to the material 14 is suppressed. Since the piezoelectric element 13 itself vibrates, suppression of vibration transmission from the outside leads to an improvement in operation accuracy of the ultrasonic transducer 20.

  The second silicone resin 19 only needs to be able to absorb the positional deviation between the substrate 15a and the circuit board KB, and only needs to have an elastic modulus sufficient to hold the substrate 15a in a predetermined position inside the case 11.

  Next, a third embodiment will be described with reference to FIG. As shown in FIG. 3, a step 32 is formed on the inner peripheral surface of the case 31 of the ultrasonic transducer 30.

  The case 31 includes a first housing portion 31 a that houses the piezoelectric element 13 and the backing material 14, and a second housing portion 31 b that houses the pin header 15. The inner diameter R1 of the first accommodating part 31a is set smaller than the inner diameter R2 of the second accommodating part 31b. That is, the step part 32 is formed at the boundary between the first accommodation part 31a and the second accommodation part 31b. An O-ring 33 made of silicone rubber is placed on the step portion 32. The elastic modulus of the O-ring 33 is preferably selected to be lower than the silicone resin 16 filled in the case 31. The material of the O-ring 33 may be the same as that of the silicone resin 16.

  On the O-ring 33, the substrate 15a of the pin header 15 is placed. In this state, the silicone resin 16 is filled into the case 31. That is, in the third embodiment, the pin header 15 is placed on the stepped portion 32 of the case 31 via the O-ring 33.

  In this manner, by placing the pin header 15 on the step portion 32 of the case 31 via the O-ring 33, a manufacturing error, an assembly error, or the like in the positional relationship between the connection pin 15b of the pin header 15 and the circuit board KB. If there is a displacement due to the position, or if the displacement is caused by vibration applied to the ultrasonic transducer 10 from the outside via the ultrasonic transducer fixing part FPb that fixes the ultrasonic transducer 10, or Even when the ultrasonic transducer 10 vibrates and the positional deviation occurs, the pin header 15 can move inside the case 31 by crushing the O-ring 33, so that the positional deviation can be absorbed. The stress concentration on the connection pin 15b is suppressed. As a result, it is possible to suppress the occurrence of connection failure between the connection pin 15b and the circuit board KB.

  Further, the pin header 15 can be positioned by placing the pin header 15 on the O-ring 33, and a jig can be dispensed with when the silicone resin 16 is filled.

10, 20, 30 Ultrasonic vibrator, 11, 31 case, 12 matching layer, 13 piezoelectric element, 14 backing material, 15 pin header, 15a substrate, 15b connection pin, 15c fixing resin, 16 silicone resin, 17a, 17b lead Wire, 18 1st silicone resin, 19 2nd silicone resin, 31a 1st accommodation part, 31b 2nd accommodation part, 32 steps, 33 O-ring, KB circuit board, FPa circuit board fixing part, more than FPb Sound wave oscillator fixing part.

Claims (4)

A cylindrical case, a piezoelectric element disposed on one end side inside the case, a substrate disposed on the other end side inside the case and electrically connected to the piezoelectric element, and fixed to the substrate An ultrasonic transducer comprising a connection pin with one end led out of the case and a resin filled in the case;
The ultrasonic vibrator, wherein the substrate is held by the resin in a non-contact state with respect to the case. The ultrasonic transducer according to claim 1,
The resin has a first resin filled around the piezoelectric element and a second resin filled around the substrate,
The ultrasonic vibrator according to claim 1, wherein an elastic modulus of the first resin is smaller than an elastic modulus of the second resin. The ultrasonic transducer according to claim 1, wherein
The ultrasonic transducer according to claim 1, wherein the substrate is held by the case via an elastic member. The ultrasonic transducer according to claim 3,
The ultrasonic vibrator is characterized in that the elastic member is an annular silicone rubber.

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