Sound transducer arrangement
11202155 · 2021-12-14
Assignee
Inventors
Cpc classification
International classification
Abstract
A MEMS sound transducer for generating and/or detecting sound waves in the audible wavelength spectrum includes a carrier: a diaphragm connected to and deflectable with respect thereto the carrier and a piezoelectric element spaced apart from the diaphragm along a reciprocation axis. The piezoelectric element includes a coupling element that extends along the reciprocation axis and connects to the diaphragm. The piezoelectric element and the coupling element form a cantilever. The MEMS sound transducer includes two cantilever arms are arranged one behind the other, in a top view.
Claims
1. A MEMS sound transducer for generating and/or detecting sound waves in the audible wavelength spectrum, the MEMS sound transducer comprising: a carrier; a diaphragm connected to the carrier and deflectable with respect thereto along a reciprocation axis; a piezoelectric element configured for generating and/or detecting a deflection of the diaphragm, the piezoelectric element is spaced apart from the diaphragm in the direction of the reciprocation axis, the piezoelectric element defines a first end connected to the carrier and a second end deflectable in the direction of the reciprocation axis; and a coupling element, which extends in the direction of the reciprocation axis between the piezoelectric element and the diaphragm and connects the second end of the piezoelectric element to the diaphragm; wherein the coupling element defines a side, which faces away from the piezoelectric element and is spaced apart from the carrier and defines a void between the side and the carrier; wherein the piezoelectric element and the coupling element form a first cantilever arm that defines a clamped end formed by the first end of the piezoelectric element and a free end formed by the coupling element; wherein the first cantilever arm defines a pair of longitudinal sides extending from the free end to the clamped end, and wherein the void has a U-shape, in a top view taken along the reciprocation axis, so that the free end of the first cantilever arm is spaced apart from the carrier and each of the longitudinal sides is spaced apart from the carrier; and wherein the MEMS sound transducer includes a second cantilever arm, and the two cantilever arms are arranged one behind the other in a view taken in a direction that is perpendicular to the reciprocation axis.
2. The MEMS sound transducer as in claim 1, wherein the free end of the first cantilever arm is connected exclusively to the diaphragm.
3. The MEMS sound transducer as claimed in claim 1, wherein the carrier defines a recess in which the second cantilever arm is arranged, wherein the recess is completely bordered by the carrier.
4. The MEMS sound transducer as claimed in claim 3, wherein a single cantilever arm is arranged in the recess.
5. The MEMS sound transducer as claimed in claim 1, further comprising a third cantilever arm disposed between the first and second cantilever arms such that in the top view, the three cantilever arms are arranged laterally adjacent to one another.
6. The MEMS sound transducer as claimed in claim 5, wherein at least two cantilever arms are oriented oppositely with respect to one another.
7. The MEMS sound transducer as claimed in claim 1, wherein the coupling element is connected to the piezoelectric element with the aid of an elastic or flexible, articulated joint, so that the coupling element is rotatable in relation to the piezoelectric element.
8. The MEMS sound transducer as claimed in claim 1, wherein the MEMS sound transducer is a MEMS loudspeaker and/or a MEMS microphone.
9. A MEMS sound transducer for generating and/or detecting sound waves in the audible wavelength spectrum, the MEMS sound transducer comprising: a carrier; a diaphragm connected to the carrier and deflectable with respect thereto along a reciprocation axis; a first piezoelectric element configured for generating and/or detecting a deflection of the diaphragm, the first piezoelectric element is spaced apart from the diaphragm in the direction of the reciprocation axis, the first piezoelectric element defines a first end connected to the carrier and a second end deflectable in the direction of the reciprocation axis; and a coupling element, which extends in the direction of the reciprocation axis between the first piezoelectric element and the diaphragm and connects the second end of the first piezoelectric element to the diaphragm; wherein the first piezoelectric element and the coupling element form a first cantilever arm that defines a clamped end formed b the first end of the first piezoelectric element and a free end formed by the coupling element; wherein the MEMS sound transducer includes a second cantilever arm defining a clamped end spaced apart from a deflectable end, the clamped end of the second cantilever arm being disposed closer to the second end of the first piezoelectric element of the first cantilever arm than is the deflectable end of the second cantilever arm so that the two cantilever arms are arranged one behind the other in a view taken in a direction that is perpendicular to the reciprocation axis and parallel to the plane of the diaphragm when the diaphragm is not being deflected; and wherein the first cantilever arm is oriented identically with respect to the second cantilever arm.
10. The MEMS sound transducer as claimed in claim 9, wherein the identically oriented cantilever arms are connected to each other in the area of the free end with the aid of the coupling element.
11. A MEMS sound transducer for generating and/or detecting sound waves in the audible wavelength spectrum, the MEMS sound transducer comprising: a carrier; a diaphragm connected to the carrier and deflectable with respect thereto along a reciprocation axis; a piezoelectric element configured for generating and/or detecting a deflection of the diaphragm, the piezoelectric element is spaced apart from the diaphragm in the direction of the reciprocation axis, the piezoelectric element defines a first end connected to the carrier and a second end deflectable in the direction of the reciprocation axis; and a coupling element, which extends in the direction of the reciprocation axis between the piezoelectric element and the diaphragm and connects the second end of the piezoelectric element to the diaphragm; wherein the piezoelectric element and the coupling element form a first cantilever arm that defines a clamped end formed by the first end of the piezoelectric element and a free end formed by the coupling element; wherein the MEMS sound transducer includes a second cantilever arm, and the two cantilever arms are arranged one behind the other in a view taken in a direction that is perpendicular to the reciprocation axis; and wherein the piezoelectric element and the coupling element are formed from the same material.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Further advantages of the invention are described in the following exemplary embodiments. Wherein:
(2)
(3)
(4)
(5)
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(7)
(8)
(9)
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
(10)
(11) One further area of application of the MEMS sound transducer 1 can also be the generation and/or detection of ultrasonic waves, however. The MEMS sound transducer 1 can be arranged, for example, in an ultrasonic sensor, for example, a distance sensor.
(12) Furthermore, the MEMS sound transducer 1 comprises a carrier 2, which can form a framework of the MEMS sound transducer 1. The carrier 2 can comprise, for example, a semiconductor substrate, which can be manufactured in an etching process. A diaphragm 3 (not shown here in
(13) In order to detect and/or generate the deflection of the diaphragm 3, the MEMS sound transducer 1 comprises at least one piezoelectric element 5 spaced apart from the diaphragm 3 in the direction of the reciprocation axis 4 as shown in
(14) As shown in
(15) The MEMS sound transducer 1 also comprises a coupling element 8, which extends in the direction of the reciprocation axis 4 between the piezoelectric element 5 and the diaphragm 3 and connects the second end 7 of the piezoelectric element 5 to the diaphragm 3. The coupling element 8 therefore transmits the deflection of the piezoelectric element 5 onto the diaphragm 3 when the MEMS sound transducer 1 is operated as a loudspeaker. In addition, the coupling element 8 transmits the deflection of the diaphragm 3 onto the piezoelectric element 5 when the MEMS sound transducer 1 is operated as a microphone.
(16) Preferably, as shown in
(17) Moreover, the at least one piezoelectric element 5 and the coupling element 8, together, form a cantilever arm 9 clamped on one side. The cantilever arm 9 comprises a clamped end 10, formed by the first end 6 of the piezoelectric element 5, and a free end 11 formed by the coupling element 8. The piezoelectric element 5, together with the coupling element 8, can form a cantilever, which is connected to the carrier 2 at the clamped end 10. The free end 11 of the cantilever arm 9 can oscillate freely when it is connected exclusively to the diaphragm 3. In particular, the free end 11 has neither connection to the carrier 2 nor to any second piezoelectric element that is oppositely positioned beneath the piezoelectric element 5 depicted in
(18) In addition, a high linearity is established as a result. The amplitude of the electrical signal can be converted into a linearly proportional amplitude of the sound waves. The same applies when the MEMS sound transducer 1 is operated as a microphone. In that case, the amplitude of the sound waves can be converted into a linearly proportional electrical signal. Furthermore, with the aid of the cantilever arm 9, the diaphragm 3 can be deflected with the aid of a great force, since the free end 11 can move unimpeded.
(19) Furthermore, as shown in
(20) Furthermore, according to the present exemplary embodiment from
(21) Moreover, as shown in
(22) In the description of the following exemplary embodiments, identical reference numerals are utilized for features that are identical or at least comparable in terms of their design and/or mode of operation as compared to the preceding exemplary embodiments. Provided these features are not explained in detail once again, their design and/or mode of operation correspond(s) to the design and mode of operation of the features already described above.
(23)
(24) Moreover, the diaphragm 3 can be arranged in the area of a top side 21 of the MEMS sound transducer 1. Furthermore, the MEMS sound transducer 1 comprises an underside 20 positioned opposite the top side 21 in the direction of the reciprocation axis. According to the present exemplary embodiment, the piezoelectric element 5 can be arranged in the region of the underside 20. Consequently, the coupling element 8 extends from the piezoelectric element 5 from the underside 20 to the diaphragm 3 at the top side 21.
(25) According to the present exemplary embodiment, the MEMS sound transducer 1 comprises a coupling plate 16, which is arranged between the coupling element 8 and the diaphragm 3 and couples these to one another. The coupling plate 16 is arranged in the area of the top side 21 of the MEMS sound transducer 1. With the aid of the coupling plate 16, a planar force transmission between the coupling element 8 and the diaphragm 3 is established.
(26)
(27) Furthermore, the two cantilever arms 9a, 9b are oriented opposite to each other in the sense that the two free ends 11a, 11b of the two cantilever arms 9a, 9b, respectively, face toward one another. The two cantilever arms 9a, 9b are connected to one another only via the diaphragm 3. The two cantilever arms 9a, 9b are arranged offset from the other in this case. “Arranged offset from the other” can mean, in this case, that the at least two cantilever arms 9a, 9b are merely offset with respect to one another in a translatory manner in a transverse direction of the MEMS sound transducer 1 as shown in
(28) The MEMS sound transducer 1 of the exemplary embodiment from the present
(29)
(30) The diaphragm 3 extends beyond the middle piece 17. According to the present exemplary embodiment from
(31) With the aid of the two cantilever arms 9a, 9b, the diaphragm 3 can be deflected to an even greater extent. In addition, the diaphragm 3 can be deflected with the aid of a greater force and uniformly in a planar manner.
(32)
(33) The two cantilever arms 9a, 9b have no direct connection to one another. The two cantilever arms 9a, 9b thus are decoupled from one another. The respective free ends 11a, 11b of the two cantilever arms 9a, 9b are both connected only to the diaphragm 3.
(34) With the aid of the arrangement of the cantilever arms 9a, 9b adjacent to one another and the arrangement one behind the other, the multiple cantilever arms 9a, 9b can be arranged in a planar manner. At least three cantilever arms 9 are necessary for this purpose. For example, two cantilever arms 9a, 9b can be arranged according to the exemplary embodiment shown here in
(35) Alternatively, cantilever arms can also be arranged in another geometric figure, wherein the number of corners of the geometric figure corresponds to the number of cantilever arms. For example, four cantilever arms can be arranged in a square, a rectangle, a trapezoid, a rhombus, or an irregular quadrilateral.
(36)
(37) The first longitudinal side 19a and the second longitudinal side 19b of the cantilever arm 9 shown in
(38)
(39) The gap 18, according to the present exemplary embodiment of
(40) Additionally, the two cantilever arms 9a, 9b can also comprise the articulated joint 14a-d (not shown here) or connecting elements. As a result, the coupling elements 8a, 8b of the cantilever arms 9a, 9b, respectively, can rotate with respect to the corresponding piezoelectric elements 5a, 5b, so that, during the deflection of the diaphragm 3, the coupling elements 8a, 8b remain aligned in parallel to the diaphragm 3.
(41) The cantilever arms 9a, 9b are arranged one behind the other in this case. The at least two cantilever arms 9a, 9b can therefore be arranged on a line. In one alternative exemplary embodiment, multiple, for example, three, four, cantilever arms 9 can also be arranged one behind the other, in particular on a line. Additionally, at least one cantilever arm 9 can also be arranged adjacent to at least one of the cantilever arms 9a, 9b shown here. Two adjacently arranged cantilever arms 9a, 9b are shown, for example, in
(42)
(43) Furthermore, according to
(44) In this case as well, multiple cantilever arms 9a, 9b can once again be arranged adjacent one another, as shown, for example, in
(45) The present invention is not limited to the represented and described exemplary embodiments. Modifications within the scope of the claims are also possible, as is any combination of the features, even if they are represented and described in different exemplary embodiments.
LIST OF REFERENCE NUMERALS
(46) 1 MEMS sound transducer 2 carrier 3 diaphragm 4 reciprocation axis 5 piezoelectric element 6 first end 7 second end 8 coupling element 9 cantilever arm 10 clamped end 11 free end 12 open region 13 recess 14 articulated joint 15 support element 16 coupling plate 17 middle piece 18 gap 19 longitudinal side 20 underside 21 top side 22 spacer element