ULTRASOUND TRANSDUCER

Abstract

An ultrasound transducer is provided. The ultrasound transducer include at least one emitter made from a piezoelectric material, having first and second emitting surfaces opposite one another provided to emit first and second ultrasound beams. The transducer comprises at least first and second mirrors placed across from the first and second emitting surfaces, respectively, and configured so as to deflect back the first and second ultrasound beams by forming a reflected beam with a predetermined shape.

Claims

1-18. (canceled)

19. An ultrasound transducer comprising: at least one emitter made from a material configured to convert an electrical signal into an ultrasonic wave, the at least one emitter having first and second emitting surfaces opposite one another provided to emit first and second ultrasound beams; and at least first and second mirrors placed so as to be across from the first and second emitting surfaces, respectively, and configured in a manner such as to deflect back deflect back the first and second ultrasound beams by forming a reflected beam with a predetermined shape.

20. The ultrasound transducer as recited in claim 19 further comprising a housing box to which the emitter is attached.

21. The ultrasound transducer as recited in claim 20 wherein the housing box has two reflective surfaces defining the first and second mirrors, or the first and second mirrors are attached on to the housing box.

22. The ultrasound transducer as recited in claim 20 wherein the housing box has a slot in which the emitter is engaged, the slot having a cross section that is substantially identical to that of the emitter.

23. The ultrasound transducer as recited in claim 20 wherein the housing box is integrally formed as a single piece or comprises of two half housing boxes encasing the emitter therebetween.

24. The ultrasound transducer as recited in claim 23 wherein each half housing box defines one of the first and second mirrors, or the first mirror is attached on to one of the two half housing boxes and the second mirror is attached on to the other of the two half housing boxes.

25. The ultrasound transducer as recited in claim 20 wherein the transducer is immersed in an ambient medium, with the first and second emitting surfaces being arranged in relation to the housing box in order to ensure that the first and second ultrasound beams are propagated from the first and second emitting surfaces right up to the first and second mirrors through the ambient medium or through a material constituting the housing box.

26. The ultrasound transducer as recited in claim 19 further comprising electrical wires that are able to be connected to a voltage source, and a clamp that clamps the electrical wires against the emitter in a manner so as to secure the electrical wiring to the emitter without soldering.

27. The ultrasound transducer as recited in claim 19 further comprising a protective layer covering the first and second emitting surfaces.

28. The ultrasound transducer as recited in claim 19 wherein the first and second ultrasound beams present first and second directions of propagation from the first and second emitting surfaces, the first and second mirrors being planar and having first and second normals forming an angle comprised between 30° and 60° in relation to the first and second directions of propagation.

29. The ultrasound transducer as recited in claim 19 wherein the first and second mirrors are concave to the first and second emitting surfaces.

30. The ultrasound transducer as recited in claim 19 wherein the first and second mirrors are convex to the first and second emitting surfaces.

31. The ultrasound transducer as recited in claim 19 wherein the emitter is a plate, with the first and second emitting surfaces being two large parallel surfaces of the plate that are positioned opposite one other.

32. The ultrasound transducer as recited in claim 19 wherein the emitter is a cylinder or a tube that is radially polarized, with the first and second emitting surfaces being two radial surfaces that are diametrically opposed.

33. The ultrasound transducer as recited in claim 19 further comprising at least one sensor provided in order to measure the shape and intensity of the ultrasonic waves, arranged in one of the first and second mirrors.

34. The ultrasound transducer as recited in claim 33 wherein the first and second mirrors present first and second reflective surfaces, the sensor being positioned to be flush with one of the first and second reflective surfaces.

35. The ultrasound transducer as recited in claim 33 wherein the sensor includes a head made from a piezoelectric crystal.

36. The ultrasound transducer as recited in claim 33 wherein the sensor includes a thin layer of a material that is configured to convert an ultrasonic wave into electrical voltage, for example a piezoelectric crystal, covering one of the first and second mirrors.

Description

BRIEF SUMMARY OF THE DRAWINGS

[0062] Other features and advantages of the invention will emerge from a detailed description which is provided here below, purely on an indicative basis and without any limitation, in reference to the annexed figures, among which:

[0063] FIG. 1 is a simplified schematic representation of a transducer that is in conformity with an embodiment of the invention;

[0064] FIG. 2 is a view that is similar to that of FIG. 1, showing variants of the embodiment of the invention;

[0065] FIG. 3 and FIG. 4 are views that are similar to those of FIG. 1, showing variants of shape and form for the mirrors of the transducer; and

[0066] the FIGS. 5 and 6 are views that are similar to those of FIG. 2, illustrating another aspect of the invention; and

[0067] FIGS. 7 and 8 are views that are similar to those of FIG. 1, showing yet other variants of the embodiment of the invention.

DETAILED DESCRIPTION

[0068] The ultrasound transducer 1 represented in FIG. 1 is intended to be used in a fluid, for example under water. It is intended for example for use in carrying out the inspection of the pressurised water reactor vessel during the unit outages. It may also be mounted permanently on the pressurised water reactor vessel, for performing measurements of temperature and/or flow rate. It may even be used for the inspection of internal equipment within the reactors where the heat transfer fluid is sodium, or for performing physical measurements (temperature, flow rate) on these same reactors. It may also be used in the medical or therapeutic field, for marine SONAR application, as position sensor or metrology sensor in all kinds of applications, or even for the cleaning of parts.

[0069] The transducer 1, as is visible in FIG. 1, includes an emitter 3 made out of a material that makes it possible to convert an electrical voltage into an ultrasonic wave, and a housing box 5.

[0070] The emitter 3 presents first and second emitting surfaces 7, 9 located opposite one another, provided in order to emit first and second ultrasound beams F1 and F2.

[0071] The housing box 5 defines the first and second mirrors 11, 13, placed so as to be across from the first and second emitting surfaces 7, 9 respectively.

[0072] The first and second mirrors 11, 13 are configured form-wise in a manner such as to deflect back the first and second ultrasound beams by forming a reflected beam FR with a predetermined shape.

[0073] The housing box 5 is made out of stainless steel. It has a slot 15 in which the emitter 3 is engaged.

[0074] The two mirrors 11 and 13 are arranged on one front surface of the housing box 5. It delimits together a hollow zone 17 on this front face. More precisely, the first and second mirrors 11 and 13 are two planar surfaces converging towards each other. As is visible in FIG. 1, the slot 3 defines the bottom of the hollow zone, the first and second mirrors converging towards the slot. The slot is open both on the side of the front face of the mirror and on the side of the rear face 19 of the housing box, this rear face 19 being positioned to be opposite the front face 17. In the example shown, the first and second mirrors 11 and 13 form an angle of 90° relative to each other.

[0075] The forward direction here corresponds to the direction of propagation of the reflected beam. The rearward direction is the opposite of the forward direction.

[0076] In the example represented in FIG. 1, the emitter 3 is a thin plate made from piezoelectric crystal. It includes an intermediate portion 21 engaged in the slot 15, a front part 23 protruding forwards towards the front out of the slot 15, a rear part 25 protruding out of the slot 15, towards the rear. The emitter 3 has first and second large surfaces 27, 29, positioned to be opposite one another. The zones of the first and second large surfaces 27, 29 delimiting the front part 23 of the emitter constitute the first and second emitting surfaces 7 and 9. The first and second emitting surfaces 7 and 9 therefore form an angle of 45° with the first and second mirrors 11 and 13.

[0077] The emitter 3 is attached to the housing box 5 by cooperation of form between the portion 21 and the slot 15 or by means of bonding of the portion 21 within the interior of the slot 15.

[0078] The functioning of the ultrasound transducer is as follows.

[0079] The first and second emitting surfaces 7, 9 emit the first and second ultrasound beams F1 and F2 that are propagated along the first and second directions of propagation. The first and second directions of propagation are substantially perpendicular to the surfaces 7 and 9. They form an angle of 45° in relation to the normals of the first and second mirrors 11 and 13. The first and second ultrasound beams are reflected on the first and second mirrors 11 and 13 and form a reflected beam FR. The first and second ultrasound beams are reflected at 90°, in the direction wherein the direction of propagation of the reflected beam is at 90° from the first and second directions of propagation, as is shown by the arrows in FIG. 1.

[0080] A variant of the embodiment of the invention will now be described with reference to the FIG. 2. Only the points whereby this variant embodiment differs from the one shown in FIG. 1 will be detailed here below.

[0081] As is visible in FIG. 2, the transducer includes a protective layer 31 covering the emitter. The protective layer is made of an elastomeric material. It covers the first and second emitting surfaces 7 and 9. It also covers the two large surfaces 27 and 29, almost in their entirety. In particular, the layer 31 is interposed between the intermediate portion 21 and the edge of the slot 15. On the other hand, the layer 31 does not cover a rear edge 32 of the emitter 3.

[0082] In addition, the transducer 1 includes electrical wires 33, 35, connected to a voltage source that has not been represented. The electrical wires 33 and 35 are pressed flat respectively against the first and second large surfaces 27, 29 of the emitter 3, at the level of the rear edge 32. As the latter is not covered by the protective layer 31, it is thus possible for electrical contact to be made between the electrical wires 33 and 35 and emitter. The electrical wires 33 and 35 are maintained in position by a clamp that is not represented. They are not soldered to the emitter.

[0083] The rear part 25 of the emitter is housed in a recessed cavity 37 provided in the housing box 5. This part, as well as the connections between the electrical wires 33 and 35 and the rear edge 32, are thus protected from aggressive external or environmental elements. The housing box 5 has an orifice 39, which brings about communication between the cavity 37 and the exterior. The electrical wires 33 and 35 come out of the housing box through the orifice 39.

[0084] The housing box 5 consists of two half housing boxes 40 between which is clamped the emitter 3. Each half housing box 40 defines one of the first and second mirrors 11, 13. The slot 15 is delimited between the two half housing boxes 40. The half housing boxes 40 are attached to one another by any appropriate means: screws, soldering, etc.

[0085] The FIGS. 3 and 4 represent two variants of embodiment of the invention, in which the mirrors 11 and 13 are not planar.

[0086] In FIG. 3, the mirrors 11 and 13 are concave towards the first and second emitting surfaces 7 and 9. The concavity is calculated so as to ensure that the reflected beam has a concentric wave front. The reflected beam FR is then focused on a point P, situated at a distance toward the front of the emitter.

[0087] In FIG. 4, the first and second mirrors 11 and 13 are convex towards the first and second emitting surfaces 7 and 9. The first and second mirrors 11 and 13 are arranged so as to ensure that the reflected beam has a diverging wave front.

[0088] A second aspect of the invention will now be detailed, in reference to the FIGS. 5 and 6. Only the points whereby the transducers shown in the FIGS. 5 and 6 differ from those shown in the FIGS. 2 and 1 respectively will be detailed here below. The elements that are identical or that provide the same function in the FIGS. 2 and 1 as in the FIGS. 5 and 6 shall be denoted by the same reference numerals.

[0089] In the examples of embodiment shown in the FIGS. 5 and 6, the transducer 1 includes at least one sensor 41 provided in order to measure the shape or intensity of the ultrasonic waves. This sensor 41 is arranged in one of the first and second mirrors.

[0090] In the example shown in FIG. 5, the transducer includes two identical sensors 41, arranged so as to locate one in the first mirror 11 and the other in the second mirror 13.

[0091] The housing box 5 includes two channels 43, opening out on one side in the cavity 37 and on the other side, on to the first and second reflective surfaces 45 and 47 of the first and second mirrors. Each sensor 41 has a head 49 made of a piezoelectric crystal, engaged in the channel 43. The head 49 is positioned to be flush with the first or second reflecting surface. The sensor, more precisely, is the head 49 of the sensor, and is thus flush with the first or the second reflecting surface. The head 49 presents a free surface 51, which forms an integral part of the continuity of the reflecting surface 45 or 47.

[0092] Each sensor 41 further includes at least one electrical power line (not shown) electrically connected to the head 49. This line traverses through the channel 43, leads out into the cavity 47 and exits out of the housing box through the orifice 39. It is connected for example to a computing unit.

[0093] In the variant of embodiment shown in FIG. 6, each sensor 41 comprises a thin layer 51 of a piezoelectric crystal, covering the first or the second mirror 11, 13. Each sensor 41 also includes a plurality of electrodes 53 electrically connected to different points of the thin layer 51. These electrodes 53 are connected by electrical wires to a computing unit. The thin layer 51 covers the entire reflective surface 45, 47, of the first and second mirrors. Thus, it is possible to control the shape of the ultrasonic signal emitted by different zones of the mirror.

[0094] A variant of the embodiment of the invention will now be described with reference to FIG. 7. Only the points whereby this variant embodiment differs from the one shown in FIG. 1 will be detailed here below.

[0095] In the variant of the embodiment shown in FIG. 1, the transducer 1 is intended to be immersed in an ambient medium such as water. The first and second emitting surfaces 7, 9 are arranged in relation to the housing box 5 in order to ensure that the first and second ultrasound beams F1, F2 are propagated from the first and second emitting surfaces 7, 9 right up to the first and second mirrors 11, 13 through the ambient medium.

[0096] The reflected beam FR is transmitted by the ambient medium to the piece in which the ultrasonic wave is transmitted.

[0097] In the variant of the embodiment shown in FIG. 7, the transducer 1 is capable of sending the reflected beam FR directly into the piece in which the ultrasonic wave is transmitted 55, without the transmission taking place through the ambient medium.

[0098] To this end, the first and second emitting surfaces 7, 9 are arranged in relation to the housing box 5 in order to ensure that the first and second ultrasound beams F1, F2 are propagated from the first and second emitting surfaces 7, 9 right up to the first and second mirrors 11, 13 through the material constituting the housing box 5.

[0099] The first and second emitting surfaces 7, 9 of the emitter 3 are then pressed flat against the wave input surfaces 57 of the housing box. In the example represented, the wave input surfaces 57 delimit the slot 15 in which the emitter 3 is engaged. The wave output surfaces 59 of the housing box 5 are pressed flat against the piece in which the ultrasonic wave is transmitted 55. In the example represented, the wave output surfaces 59 are pressed flat directly against the piece 55. In a variant represented in FIG. 8, a wedge 61 is interposed between the wave output surfaces 59 and the piece 55. The wedge for example makes it possible to adjust the direction of propagation of the ultrasonic beam in the piece in which the ultrasonic wave is transmitted.

[0100] By way of a variant, the housing box 5 and the wedge 61 are integrally formed as a single unit and constitute one same piece. The mirrors are therefore somewhat longer (they exceed the extreme end point of the emitter) and directly incorporate the angle in order to cause deflection of the ultrasound beam in the piece (below the critical angle).

[0101] The first and second mirrors 11, 13, the wave input surfaces 57 and the wave output surfaces 59 are arranged in order to ensure that the first and second ultrasound beams F1, F2 penetrating into the housing box 5 through the input surfaces 57 are reflected by the first and second mirrors 11, 13 right to the output surfaces 59. The reflected beam FR is propagated in the interior of the housing box 5, exits the housing box 5 through the output surfaces 59 and penetrates into the piece in which the ultrasonic wave is transmitted 55.