JP5111977B2 - Ultrasonic transducer - Google Patents

Description

  The present invention relates to an ultrasonic transducer that transmits and receives an ultrasonic frequency band.

In the ultrasonic transducer according to the conventional embodiment, when an ultrasonic transducer is embedded in a vehicle bumper or the like and an obstacle around the vehicle is to be detected, pulse burst electrical is applied to the ultrasonic transducer. By inputting the signal, an ultrasonic signal corresponding to the input pulse burst electric signal is oscillated from the ultrasonic transducer, and the oscillated ultrasonic signal reaches the obstacle, and the ultrasonic signal hits the obstacle. Is reflected by the obstacle, and a part of the reflected ultrasonic signal returns to the same ultrasonic transducer. The ultrasonic transducer detects an obstacle by receiving the reflected signal. At this time, ultrasonic waves were transmitted and received using the primary vibration mode of the ultrasonic transducer. For this reason, a small sensor such as φ14 mm having a primary vibration mode in the vicinity of 40 to 50 kHz is used as a corner sensor for detecting a relatively short distance. This is used for long distance detection such as a back sensor. When used, the directivity is wide and erroneous detection due to road surface detection occurs. For this reason, ultrasonic transducers for long-distance detection applications such as back sensors have been used that have the primary vibration mode changed in frequency or increased in outer diameter. On the other hand, when this is used for the detection of near-field maps such as corner sensors, there is a problem that the directivity is too narrow and the detection range is not sufficient, so the ultrasonic transmission and reception related to the conventional embodiment In the vessel, a plurality of types of sensors, such as changing the frequency of the primary vibration mode or changing the outer diameter, had to be used.
FIG. 4 is a schematic longitudinal sectional view of an ultrasonic transducer according to a conventional embodiment. In FIG. 4, the piezoelectric element 1 is bonded inside the bottom surface of the bottomed cylindrical case 2 made of an aluminum material or the like to form a unimorph vibrator. The input / output lead 5a is taken out from the opposite surface of the piezoelectric element 1 to the bottomed cylindrical case 2 and the input / output lead 5b is taken out from the bottomed cylindrical case 2 by soldering or the like. The adhesive surface side of the piezoelectric element 1 with the bottomed cylindrical case 2 and the bottomed cylindrical case 2 are electrically connected. Further, the piezoelectric element 1, the input / output lead 5a, and the bottomed cylindrical case 2 are electrically connected. And the input / output lead 5b are electrically connected. The input / output leads 5a and 5b are soldered to the wire lead 6 with a connector, respectively. A sound absorbing material 3 made of a silicon foam or the like is placed on the upper surface of the piezoelectric element 1, and a sealing agent 4 made of an elastic material such as a silicon material or a urethane material is placed in the bottomed cylindrical case 2. Fill and configure.
Tanikoshi Shinji “Ultrasound and its usage-Ultrasonic transducers and ultrasonic motors” Nikkan Kogyo Shimbun 1994

  It is to supply an ultrasonic transducer that can be used for either one type of sensor without using two types of ultrasonic transducers for a corner sensor, a back sensor, or the like.

A unimorph vibrator is formed by laminating a piezoelectric element inside the bottom surface of a bottomed cylindrical case, and an ultrasonic transducer that transmits and receives ultrasonic waves on the outer surface of the case has a bottomed cylindrical shape. A continuous annular groove is provided on the piezoelectric element bonding surface of the case, and the piezoelectric element is bonded so as to cover the groove portion. Alternatively, a plurality of annular grooves are provided on the piezoelectric element bonding surface of the bottomed cylindrical case so as to be double or more, and the piezoelectric elements are bonded so as to cover all or part of the groove portions. Or a thin part is provided in the piezoelectric element adhesion surface of a bottomed cylindrical case, and a piezoelectric element is bonded together so that the thin groove part may be covered. Furthermore, a piezoelectric element hollowed out inside is attached to a bottomed cylindrical case, and a piezoelectric element having a shape smaller than the hollowed portion and not in contact with the hollowed portion is inserted into the hollowed cylindrical case. to paste together. As a result, a plurality of resonance modes corresponding to the primary vibration mode can be generated, and the ultrasonic transducer can be driven at each resonance frequency.

  According to the present invention, an ultrasonic transducer having a resonance mode corresponding to a plurality of primary vibration modes can be used for either one type of sensor without using two types of ultrasonic transducers for a corner sensor, a back sensor, etc. Possible ultrasonic transducers can be supplied.

  When used for a back sensor, a corner sensor, etc., one kind of ultrasonic transducer is embedded in a car bumper or the like and is driven at a resonance frequency according to the purpose of use to detect an obstacle.

FIG. 1 shows a schematic top view and a longitudinal sectional view of a bottomed cylindrical case in an ultrasonic transducer according to an embodiment of claim 1 of the present invention. In FIG. 1, a continuous annular groove 7a is provided inside the bottom surface of a bottomed cylindrical case 2 made of an aluminum material or the like, and the piezoelectric element 1 is bonded so as to cover the groove portion to form a unimorph vibrator. To do.
FIG. 2 is a schematic top view and longitudinal sectional view of a bottomed cylindrical case in an ultrasonic transducer according to an embodiment of claim 2 of the present invention. In FIG. 2, a plurality of annular grooves 7 provided inside the bottom surface of the bottomed cylindrical case 2 made of an aluminum material or the like are provided so as to be double or more. Here, the grooves 7a and 7b are used. The piezoelectric element 1 is bonded so as to cover the groove 7a to form a unimorph vibrator.
In these, it is desirable that the outer peripheral dimension of the annular groove 7a provided in the bottomed cylindrical case 2 is smaller than the outer peripheral dimension of the piezoelectric element as shown in FIG.
FIG.5 and FIG.5b represents the schematic top view and longitudinal cross-sectional view of the bottomed cylindrical case in the ultrasonic transmitter / receiver concerning another embodiment of this invention. The grooves 7a and 7b provided in the bottomed cylindrical case 2 may be ring-shaped as shown in FIG. 5a, and even if the grooves 7a and 7b are divided in the middle, they have the same effect and are included in the present invention. . Further, as shown in FIG. 5b, the groove provided in the bottomed cylindrical case is not formed of only a single part or material, but a thin-walled portion is provided in the bottomed cylindrical case, and another plate 8 is adhered thereon. Then, it may be formed of a plurality of parts.
FIG. 3 shows a schematic top view and a longitudinal sectional view of a bottomed cylindrical case in an ultrasonic transducer according to an embodiment of claim 4 of the present invention. In FIG. 3, the piezoelectric element 9 hollowed in the center is bonded to the bottomed cylindrical case, and another piezoelectric element 10 is bonded to the bottomed cylindrical case in the hollowed portion of the piezoelectric element to form a unimorph vibrator. Moreover, even when there is no groove 7a provided in the bottomed cylindrical case, the same effect is obtained.
FIG. 6a is a schematic longitudinal sectional view of an ultrasonic transducer according to the first and second embodiments of the present invention. In FIG. 6a, the piezoelectric element 1 is bonded inside the bottom surface of the bottomed cylindrical case 2 to form a unimorph vibrator. The input / output leads 5a are taken out from the surface of the piezoelectric element 1 opposite to the bonding surface with the bottomed cylindrical case 2, and the input / output leads 5b are taken out from the bottomed cylindrical case 2 by soldering or the like. The bonding surface side of the piezoelectric element 1 with the bottomed cylindrical case 2 and the bottomed cylindrical case 2 are electrically connected. Further, the piezoelectric element 1, the input / output lead 5a, and the bottomed cylindrical case 2 are connected. And the input / output lead 5b are electrically connected. The input / output leads 5a and 5b are soldered to the wire lead 6 with a connector, respectively. A sound absorbing material 3 made of a silicon foam or the like is placed on the upper surface of the piezoelectric element 1, and a sealing agent 4 made of an elastic material such as a silicon material or a urethane material is placed in the bottomed cylindrical case 2. Fill and configure. FIG. 6 b shows a schematic longitudinal sectional view of an ultrasonic transducer according to an embodiment of claim 4 of the present invention. In FIG. 6b, the piezoelectric element 9 and the piezoelectric element 10 are bonded inside the bottom surface of the bottomed cylindrical case 2 to form a unimorph vibrator. The input / output lead 5a from the opposite surface of the piezoelectric element 9 to the bottomed cylindrical case 2 and the input / output lead 5c from the opposite surface of the piezoelectric element 10 to the bottomed cylindrical case 2 are provided. The input / output lead 5b is taken out from the bottom cylindrical case 2 by soldering or the like. The bonding surface side of the piezoelectric elements 9 and 10 with the bottomed cylindrical case 2 and the bottomed cylindrical case 2 are electrically connected. Further, the input / output leads 5a to and from the piezoelectric element 9 and the piezoelectric element 10 are connected. The input / output lead 5c and the bottomed cylindrical case 2 are electrically connected to the input / output lead 5b. A sound absorbing material 3 made of a silicon foam or the like is placed on the upper surface of the piezoelectric element 1, and a sealing agent 4 made of an elastic material such as a silicon material or a urethane material is placed in the bottomed cylindrical case 2. Fill and configure. The piezoelectric element 9 is driven using the input / output leads 5a and 5b, and the piezoelectric element 10 is driven using the input / output leads 5c and 5b.
FIG. 7 shows impedance characteristics of the ultrasonic transducer according to the embodiment of the present invention and the ultrasonic transducer according to the conventional embodiment. As shown in FIG. 7, in the case of the ultrasonic transducer according to the conventional embodiment, the primary vibration mode is single, but in the case of the ultrasonic transducer of the present invention, it corresponds to a plurality of primary vibration modes. The resonance frequency is observed, and the ultrasonic transducer can be driven at that frequency.

  The present invention can be applied not only to a back sensor of a car but also to various fields where a drip-proof ultrasonic transducer is used.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic top view and longitudinal sectional view of a low-cylindrical case of an ultrasonic transducer according to an embodiment of claim 1 of the invention; The schematic top view and longitudinal cross-sectional view of the low and cylindrical case of the ultrasonic transducer according to the embodiment of claim 2 of the present invention The schematic top view and longitudinal cross-sectional view of a bottomed cylindrical case of the ultrasonic transducer according to the embodiment of claim 4 of the present invention Schematic longitudinal sectional view of an ultrasonic transducer according to a conventional embodiment a. Schematic top view and longitudinal cross-sectional view of a low-cylindrical case in an ultrasonic transducer according to another embodiment of the present invention b Low-low cylinder in an ultrasonic transducer according to another embodiment of the present invention Schematic top view and longitudinal section a Schematic longitudinal sectional view of an ultrasonic transducer according to an embodiment of the present invention b Schematic longitudinal sectional view of an ultrasonic transducer according to an embodiment of the present invention Impedance characteristics of ultrasonic transducers according to embodiments of the present invention and ultrasonic transducers according to conventional embodiments

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Piezoelectric element 2 Bottomed cylindrical case 3 Sound-absorbing material 4 Sealant 5a Input / output lead 5b Input / output lead
6 Wire lead with connector 7a Groove provided inside the bottom surface of the low cylindrical case 7b Groove provided inside the bottom surface of the low cylindrical case 8 Plate fixed to the thin part of the bottomed cylindrical case 9 Piezoelectric center cut Element 10 Another piezoelectric element bonded to the hollow part of the piezoelectric element 9

Claims (4)

A unimorph vibrator is formed by laminating a piezoelectric element inside the bottom surface of a bottomed cylindrical case, and an ultrasonic transducer that transmits and receives ultrasonic waves on the outer surface of the case has a bottomed cylindrical shape. a single continuous annular groove of the piezoelectric element adhering surface of the casing is provided, the allowed Awa attaching the piezoelectric element so as to cover the groove portion, and characterized in that a plurality of generating a resonant mode corresponds to the first vibration mode Ultrasonic transducer. A plurality of annular grooves are provided in the piezoelectric element bonding surface of the bottomed cylindrical case so as to be double or more, and the piezoelectric elements are bonded so as to cover all or part of the groove portions. Item 2. The ultrasonic transducer according to Item 1. 2. The ultrasonic transducer according to claim 1, wherein the annular groove is formed by placing a plate member on a thin portion provided on a piezoelectric element bonding surface of a bottomed cylindrical case . A piezoelectric element with a hollow inside is attached to a bottomed cylindrical case, and a piezoelectric element that is smaller than the hollowed portion and does not touch the hollowed portion is inserted into the hollowed portion and bonded to the bottomed cylindrical case. The ultrasonic transducer according to claim 1, wherein:

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