Directional Acoustic Sensor and Acoustic Sensor

Abstract

To provide a compact directional acoustic sensor capable of improving the signal-to-noise ratio.SOLUTION: A directional acoustic sensor 200 includes: first and second sensing devices 210, 220 having different output gains depending on input directions of external energy; and at least one signal processor. The first and second sensing devices generate at least one first output signal and at least one second output signal having mutually different polarities for the same input direction. The at least one signal processor 270 generates at least one final output signal by subtraction between the at least one first output signal and the at least one second output signal.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a directional acoustic sensor and an acoustic sensor, and more particularly to a directional acoustic sensor and an acoustic sensor capable of improving the signal-to-noise ratio. [Background technology]

[0002] Directional acoustic sensors are attached to home appliances, video display devices, virtual reality devices, augmented reality devices, and artificial intelligence speakers to detect the direction from which a sound is coming and recognize it. Directional acoustic sensors convert mechanical movement caused by pressure difference into an electrical signal to detect acoustic signals. Summary of the Invention [Problem to be solved by the invention]

[0003] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The illustrative embodiments provide directional acoustic sensors and acoustic sensors capable of improving the signal-to-noise ratio. [Means for solving the problem]

[0004] In one aspect, a directional acoustic sensor is provided that includes first and second sensing elements having different output gains depending on the input direction of external energy and generating at least one first output signal and at least one second output signal of different polarities for the same input direction; and at least one signal processor that takes a difference between the at least one first output signal and the at least one second output signal to generate at least one final output signal.

[0005] The first and second sensing elements may have the same directionality.

[0006] The first sensing element may be provided on a first substrate and include at least one first resonator that generates the at least one first output signal, and the second sensing element may be provided on a second substrate and include at least one second resonator that generates the at least one second output signal.

[0007] At least one first support portion on which the at least one first resonator is provided may be extended from the first substrate, and at least one second support portion on which the at least one second resonator is provided may be extended from the second substrate.

[0008] The first and second sensing elements may be stacked in one direction.

[0009] The first support portion may include a first surface and a second surface that is an opposite surface to the first surface, and the second support portion may include a third surface that faces the second surface and a fourth surface that is an opposite surface to the third surface.

[0010] The first resonator may include a first electrode provided on the first surface, a first piezoelectric layer provided on the first electrode, and a second electrode provided on the first piezoelectric layer, and the second resonator may include a third electrode provided on the fourth surface and having the same polarity as the first electrode, a second piezoelectric layer provided on the third electrode, and a fourth electrode provided on the second piezoelectric layer and having the same polarity as the second electrode.

[0011] The first substrate may be provided with first and second terminals electrically connected to the first and second electrodes, and the second substrate may be provided with third and fourth terminals electrically connected to the third and fourth electrodes.

[0012] The first resonator may include a first electrode provided on the second surface, a first piezoelectric layer provided on the first electrode, and a second electrode provided on the first piezoelectric layer, and the second resonator may include a third electrode provided on the third surface and having the same polarity as the first electrode, a second piezoelectric layer provided on the third electrode, and a fourth electrode provided on the second piezoelectric layer and having the same polarity as the second electrode.

[0013] The first resonator may include a first electrode provided on the first surface, a first piezoelectric layer provided on the first electrode, and a second electrode provided on the first piezoelectric layer, and the second resonator may include a third electrode provided on the third surface and having the same polarity as the second electrode, a second piezoelectric layer provided on the third electrode, and a fourth electrode provided on the second piezoelectric layer and having the same polarity as the first electrode.

[0014] The first and second sensing elements may be disposed in the same plane.

[0015] The first and second substrates may be integral with each other or spaced apart from each other.

[0016] The first resonator may include a first electrode provided on one side of the first support portion, a first piezoelectric layer provided on the first electrode, and a second electrode provided on the first piezoelectric layer, and the second resonator may include a third electrode provided on one side of the second support portion and having the same polarity as the second electrode, a second piezoelectric layer provided on the third electrode, and a fourth electrode provided on the second piezoelectric layer and having the same polarity as the first electrode.

[0017] The first sensing element may include a plurality of first resonators generating a plurality of first output signals having different center frequencies, and the second sensing element may include a plurality of second resonators generating a plurality of second output signals having different center frequencies corresponding to the plurality of first resonators.

[0018] A pair of corresponding first and second resonators having the same center frequency may generate first and second output signals, respectively, of different polarities for the same input direction.

[0019] The at least one signal processor may include a plurality of signal processors that take differences between the plurality of first output signals and the plurality of second output signals to generate a plurality of final output signals.

[0020] The at least one signal processor may include one signal processor that takes a difference between the first output signals and the second output signals to generate a final output signal.

[0021] In another aspect, a directional acoustic sensor is provided that includes a substrate; at least one first resonator and at least one second resonator stacked in one direction on the substrate, the at least one first resonator and the at least one second resonator having different output gains depending on the input direction of external energy and generating at least one first output signal and at least one second output signal of different polarities for the same input direction, respectively; and at least one signal processor that takes a difference between the at least one first output signal and the at least one second output signal and generates at least one final output signal.

[0022] The substrate may include at least one support extending therefrom, on which the at least one first resonator and the at least one second resonator are provided.

[0023] The first resonator may include a first electrode provided on a first surface of the support portion, a first piezoelectric layer provided on the first electrode, and a second electrode provided on the first piezoelectric layer, and the second resonator may include the second electrode, a second piezoelectric layer provided on the second electrode, and a third electrode provided on the second piezoelectric layer and having the same polarity as the first electrode.

[0024] The first surface of the substrate may be provided with first, second and third terminals electrically connected to the first, second and third electrodes.

[0025] The first resonator may include a first electrode provided on a first surface of the support portion, a first piezoelectric layer provided on the first electrode, and a second electrode provided on the first piezoelectric layer, and the second resonator may include a third electrode provided on a second surface of the support portion and having the same polarity as the first electrode, a second piezoelectric layer provided on the third electrode, and a fourth electrode provided on the second piezoelectric layer and having the same polarity as the second electrode.

[0026] A first surface of the substrate may be provided with first and second terminals electrically connected to the first and second electrodes, and a second surface of the substrate may be provided with third and fourth terminals electrically connected to the third and fourth electrodes.

[0027] The at least one first resonator may include a plurality of first resonators generating a plurality of first output signals having different center frequencies, and the at least one second resonator may include a plurality of second resonators generating a plurality of second output signals having different center frequencies corresponding to the plurality of first resonators.

[0028] A pair of corresponding first and second resonators having the same center frequency may generate first and second output signals, respectively, of different polarities for the same input direction.

[0029] The at least one signal processor may include a plurality of signal processors that take differences between the plurality of first output signals and the plurality of second output signals to generate a plurality of final output signals.

[0030] The at least one signal processor may include one signal processor that takes a difference between the first output signals and the second output signals to generate a final output signal.

[0031] In yet another aspect, an acoustic sensor is provided that includes a first sensing element that generates a first output signal of a first polarity and a second sensing element that generates a second output signal of a polarity different from the first polarity in response to a same external acoustic input; and a signal processor that differentiates the first output signal and the second output signal.

[0032] The first output signal and the second output signal may have opposite phases to each other.

[0033] The first sensing element and the second sensing element may be arranged to be stacked.

[0034] The first sensing element and the second sensing element may be disposed on the same plane.

[0035] The first sensing element and the second sensing element may be stacked and share a common electrode.

[0036] The first and second sensing elements may have the same directivity.

[0037] The first sensing element may include a first resonator, and the second sensing element may include a second resonator.

[0038] The first resonator and the second resonator may be disposed to face each other.

[0039] The first resonator and the second resonator may be arranged to face in different directions.

[0040] The first and second resonators may have the same centre frequency.

[0041] Each of the first and second resonators may include a pair of electrodes and a piezoelectric layer provided between the pair of electrodes.

[0042] The first sensing element may include a plurality of first resonators having different center frequencies, and the second sensing element may include a plurality of second resonators having different center frequencies corresponding to the plurality of first resonators. [Brief description of the drawings]

[0043] [Figure 1] FIG. 2 is a perspective view illustrating an example of a directional acoustic sensor. [Diagram 2] 2 is a cross-sectional view taken along line II' in FIG. [Figure 3A] 2 is a diagram showing the results of measuring the directional characteristics of the directional acoustic sensor shown in FIG. 1. [Figure 3B] 2 is a diagram showing the results of measuring the directional characteristics of the directional acoustic sensor shown in FIG. 1. [Figure 4] FIG. 1 illustrates a perspective view of a directional acoustic sensor in accordance with an illustrative embodiment. [Diagram 5] FIG. 5 is an exploded perspective view of the directional acoustic sensor shown in FIG. [Figure 6] 5 is a cross-sectional view taken along line II-II' in FIG. [Figure 7] 5 is a block diagram showing a schematic configuration of the directional acoustic sensor shown in FIG. 4. [Figure 8A] 5 is a diagram showing the results of measuring the directional characteristics of the directional acoustic sensor shown in FIG. 4. [Figure 8B] 5 is a diagram showing the results of measuring the directional characteristics of the directional acoustic sensor shown in FIG. 4. [Figure 9A] 2 is a graph showing the results of measuring the frequency response characteristics of the directional acoustic sensor shown in FIG. 1. [Figure 9B] 5 is a diagram showing a result of measuring a frequency response characteristic of the directional acoustic sensor according to the exemplary embodiment shown in FIG. 4. [Figure 10] 13 illustrates a directional acoustic sensor according to another example embodiment. [Figure 11] FIG. 13 is an exploded perspective view of a directional acoustic sensor according to yet another illustrative embodiment. [Figure 12]12 is a cross-sectional view of the directional acoustic sensor shown in FIG. 11. [Figure 13] FIG. 13 is an exploded perspective view of a directional acoustic sensor according to yet another illustrative embodiment. [Figure 14] FIG. 13 is a perspective view illustrating a directional acoustic sensor according to yet another exemplary embodiment. [Figure 15A] 15 is a cross-sectional view taken along line III-III' in FIG. 14. [Figure 15B] 15 is a cross-sectional view taken along line IV-IV' in FIG. 14. [Figure 16] FIG. 13 is a perspective view illustrating a directional acoustic sensor according to yet another exemplary embodiment. [Figure 17A] 17 is a cross-sectional view taken along line VV' in FIG. 16. [Figure 17B] 17 is a cross-sectional view taken along line VI-VI' in FIG. 16. [Figure 18] FIG. 13 is a perspective view illustrating a directional acoustic sensor according to yet another exemplary embodiment. [Figure 19A] 1 is a diagram illustrating a schematic diagram of a conventional acoustic sensor and a directional acoustic sensor according to an exemplary embodiment as an experimental model for a wake-up test. [Figure 19B] 1 is a diagram illustrating a schematic diagram of a conventional acoustic sensor and a directional acoustic sensor according to an exemplary embodiment as an experimental model for a wake-up test. [Figure 19C] 1 is a diagram illustrating a schematic diagram of a conventional acoustic sensor and a directional acoustic sensor according to an exemplary embodiment as an experimental model for a wake-up test. [Figure 20] 19B is a graph showing a comparison of wake-up success rates of the acoustic sensors shown in FIGS. 19A to 19C. [Figure 21] FIG. 13 is a perspective view illustrating a directional acoustic sensor according to yet another exemplary embodiment. [Figure 22] 22 is a cross-sectional view taken along line VII-VII' in FIG. 21. [Figure 23] 13 is a diagram illustrating a directional acoustic sensor according to yet another example embodiment. [Figure 24]FIG. 13 is an exploded perspective view of a directional acoustic sensor according to yet another illustrative embodiment. [Diagram 25] 25 is a block diagram showing a schematic configuration of the directional acoustic sensor shown in FIG. 24. [Figure 26] FIG. 26 is a block diagram showing a modified example of the directional acoustic sensor shown in FIG. 25. [Figure 27] FIG. 26 is a block diagram showing another modified example of the directional acoustic sensor shown in FIG. 25. [Figure 28] FIG. 13 is a perspective view illustrating a directional acoustic sensor according to yet another exemplary embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. In the following drawings, the same reference numerals refer to the same components, and the size of each component may be exaggerated in the drawings for clarity and convenience of description. Meanwhile, the embodiments described below are merely examples, and various modifications are possible from these embodiments.

[0045] Hereinafter, the terms "upper" and "above" include not only those immediately above, below, left, and right in contact, but also those not in contact above, below, left, and right. A singular expression includes a plural expression unless otherwise clearly indicated in the context. In addition, when a part "includes" a certain element, it does not exclude other elements, but means that it further includes other elements, unless otherwise specified to the contrary.

[0046] Use of the term "said" and similar referents refers to both the singular and the plural.

[0047] Unless a method step is expressly described in order or stated to the contrary, the steps are not necessarily limited to the order described and may be performed in any suitable order.

[0048] The use of any examples or exemplary terms is merely for the purpose of illustrating the technical concept in detail, and the scope is not limited by the examples or exemplary terms unless otherwise limited by the claims.

[0049] Fig. 1 is a perspective view showing an example of a directional acoustic sensor, and Fig. 2 is a cross-sectional view taken along line II' in Fig. 1.

[0050] 1 and 2, the directional acoustic sensor 100 includes a resonator 130 provided on a substrate 111. A cavity 111a is formed penetrating the substrate 111, and a support 112 is provided extending from the substrate 111 toward the cavity 111a. One end of the support 112 is fixed to the substrate 111, and the other end is provided so as to be movable in a vertical direction (e.g., in the z-axis direction). The substrate 111 is, for example, a silicon substrate, but is not limited thereto, and substrates made of various other materials may be used.

[0051] The resonator 130 is provided on the support 112. Specifically, the resonator 130 includes a first electrode 131 provided on one surface of the support 112, a piezoelectric layer 133 provided on the first electrode 131, and a second electrode 132 provided on the piezoelectric layer 133. The substrate 111 is provided with first and second terminals 131a, 132a electrically connected to the first and second electrodes 131, 132.

[0052] When external energy such as sound or pressure is input to the resonator 130, the piezoelectric layer 133 is deformed, generating electrical energy. For example, when sound generated from a sound source S is input to the resonator 130 and the piezoelectric layer 133 is deformed, electrical energy is generated between the first and second electrodes 131, 132, and the electrical energy is output via the first and second terminals 131a, 132a. For example, when a common voltage V com When a voltage is applied, an output signal 160 is obtained via a read circuit 150 coupled to the second terminal 132a.

[0053] 1 has different output gains depending on the input direction of external energy, that is, the directional acoustic sensor 100 has a directionality whose sensitivity changes depending on the input direction of external energy.

[0054] Figures 3A and 3B exemplarily show the results of measuring the directional characteristics of the directional acoustic sensor 100 shown in Figure 1. As shown in Figures 3A and 3B, it can be seen that the directional acoustic sensor 100 has bi-directionality, that is, directionality in the z-axis direction, which is the 0° direction and the 180° direction.

[0055] Fig. 4 is a perspective view showing a directional acoustic sensor according to an exemplary embodiment, and Fig. 5 is an exploded perspective view of the directional acoustic sensor shown in Fig. 4. Fig. 6 is a cross-sectional view taken along line II-II' in Fig. 4. Fig. 7 is a block diagram showing a schematic configuration of the directional acoustic sensor shown in Fig. 4.

[0056] 4 to 7, the directional acoustic sensor 200 includes first and second sensing elements 210 and 220, and a signal processor 270 that processes signals output from the first and second sensing elements 210 and 220. The first and second sensing elements 210 and 220 generate output signals of different polarities in response to the same external acoustic input.

[0057] The first and second sensing elements 210, 220 are stacked in one direction (e.g., the z-axis direction). The first and second sensing elements 210, 220 may be the same sensing element, and in FIG. 4, the second sensing element 220 is shown in the same form as the first sensing element 210, but turned upside down.

[0058] The first sensing element 210 includes a first resonator 230 provided on the first substrate 211. The first resonator 230 is provided to have a predetermined center frequency. A first cavity 211a is formed penetrating the first substrate 211, and a first support portion 212 is provided extending from the first substrate 211 toward the first cavity 211a. One end of the first support portion 212 is fixed to the first substrate 211, and the other end is provided so as to move in the vertical direction (for example, the z-axis direction). The first substrate 211 is, for example, a silicon substrate, but is not limited thereto, and substrates made of various other materials may be used.

[0059] The first resonator 230 is provided on the first support section 212. Specifically, the first resonator 230 includes a first electrode 231 provided on the upper surface of the first support section 212, a first piezoelectric layer 233 provided on the first electrode 231, and a second electrode 232 provided on the first piezoelectric layer 233. Here, the first and second electrodes 231, 232 are, for example, a (+) electrode and a (-) electrode, respectively. However, the present invention is not limited thereto, and the first and second electrodes 231, 232 may be a (-) electrode and a (+) electrode, respectively.

[0060] First and second terminals 231a, 232a electrically connected to the first and second electrodes 231, 232 are provided on the upper surface of the first substrate 211. Fig. 4 exemplarily illustrates a case where the first terminal 231a is located on the left side and the second terminal 232a is located on the right side on the upper surface of the first substrate 211, with respect to the +x-axis. The first sensing element 210 may have bidirectionality, for example, bidirectionality in the z-axis direction, similar to the directional acoustic sensor 100 illustrated in Fig. 1 described above.

[0061] The second sensing element 220 is provided below the first sensing element 210. As described above, the second sensing element 220 may be an element in which the first sensing element 210 is turned upside down. The second sensing element 220 includes a second resonator 240 provided on the second substrate 221. The second resonator 240 is provided so as to have the same center frequency as the first resonator 230. A second cavity 221a is formed penetrating the second substrate 221, and the second support portion 222 is provided to extend from the second substrate 221 toward the second cavity 221a. Here, the second support portion 222 has one end fixed to the second substrate 221 and the other end provided so as to move in the vertical direction (for example, the z-axis direction).

[0062] The second resonator 240 is provided on the second support section 222. Specifically, the second resonator 240 includes a third electrode 241 provided on the lower surface of the second support section 222, a second piezoelectric layer 243 provided on the third electrode 241, and a fourth electrode 242 provided on the second piezoelectric layer 243. Therefore, the first and second resonators 230, 240 are arranged so as to face in opposite directions to each other on the first and second support sections 212, 222. Here, the third electrode 241 may have the same polarity as the first electrode 231, and the fourth electrode 242 may have the same polarity as the second electrode 232. For example, when the first and second electrodes 231, 232 are (+) and (-) electrodes, respectively, the third and fourth electrodes 241, 242 are (+) and (-) electrodes, respectively.

[0063] Third and fourth terminals 241a, 242a electrically connected to the third and fourth electrodes 241, 242 are provided on the lower surface of the second substrate 221. In FIG. 4, the third terminal 241a is located on the right side and the fourth terminal 242a is located on the left side on the lower surface of the second substrate 221 when viewed from the +x-axis. The second sensing element 220 may have the same directivity as the first sensing element 210.

[0064] The first and second sensing elements 210, 220 are arranged to be operable in synchronization with the input of external energy. The first and second sensing elements 210, 220 are arranged, for example, at an interval of about 10 cm or less in the z-axis direction, more specifically, at an interval of 0 mm to 3 mm. However, this is merely an example, and the interval between the first and second sensing elements 210, 220 can be variously modified. In this way, the first and second sensing elements 210, 220 are arranged adjacent to each other, so that the directional acoustic sensor 200 can be implemented in a small size.

[0065] When external energy such as sound or pressure is input to the first and second resonators 230 and 240, electrical energy is generated from the first and second resonators 230 and 240. Specifically, when sound generated from a sound source S is input to the first resonator 230, the first piezoelectric layer 233 is deformed and electrical energy is generated between the first and second electrodes 231 and 232, and the electrical energy is output as a first output signal 261 through a first reading circuit 251 connected to the first or second terminal 231a or 232a.

[0066] Furthermore, if sound generated from the same sound source S is also input to the second resonator 240, the second piezoelectric layer 243 deforms and electrical energy is generated between the third and fourth electrodes 241, 242, and the electrical energy is output as a second output signal 262 via the second reading circuit 252 connected to the third or fourth terminal 241a, 242a.

[0067] In this embodiment, the first electrode 231 of the first resonator 230 and the third electrode 241 of the second resonator 240 are configured with the same polarity, and the second electrode 232 of the first resonator 230 and the fourth electrode 242 of the second resonator 240 are configured with the same polarity, so that the first and second resonators 230, 240 generate output signals of different polarities for the same input direction of external energy. Specifically, the first and second resonators 230, 240 generate first and second output signals 261, 262 having reverse phases of different polarities, respectively.

[0068] The signal processor 270 performs arithmetic processing on the first output signal 261 generated by the first resonator 230 and the second output signal 262 generated by the second resonator 240 to generate a final output signal 280. Specifically, the signal processor 270 generates the final output signal 280 by taking a difference between the first output signal 261 and the second output signal 262 of different polarities. This can improve the signal to noise ratio (SNR).

[0069] The first and second output signals 261, 262 generated by the first and second resonators 230, 240 are generated by the behavior of the first and second resonators 230, 240, and generally contain noise in a modulated form in the first and second output signals 261, 262. Here, the noise includes noise generated in the vibrator, intrinsic noise of the circuit, noise caused by the power supply, etc. If the sensitivity of the acoustic sensor is increased and the noise is reduced, the signal-to-noise ratio (SNR) is improved.

[0070] In this embodiment, the first and second resonators 230, 240 generate first and second output signals 261, 262 of different polarities, respectively, and the signal processor 270 is used to take the difference between the first and second output signals 261, 262 of different polarities, thereby increasing the synchronized signal and reducing the unsynchronized noise generated by the behavior of the first and second resonators 230, 240, thereby obtaining a final output signal 280 with an improved signal-to-noise ratio (SNR).

[0071] The directional acoustic sensor 200 including the first and second sensing elements 210 and 220 shown in Fig. 4 may have a directivity with different output gains depending on the input direction of external energy. Fig. 8A and Fig. 8B show the results of measuring the directional characteristics of the directional acoustic sensor 200 according to the exemplary embodiment shown in Fig. 4. As shown in Fig. 8A and Fig. 8B, it can be seen that the directional acoustic sensor 200 has bidirectionality, i.e., directionality in the z-axis direction, which is the 0° direction and the 180° direction.

[0072] Fig. 9A shows the result of measuring the frequency response characteristic of the directional acoustic sensor 100 shown in Fig. 1. Referring to Fig. 9A, the signal-to-noise ratio (SNR) of the directional acoustic sensor 100 was measured to be approximately 44.6 dB.

[0073] 9B illustrates a result of measuring the frequency response characteristic of the directional acoustic sensor according to the exemplary embodiment shown in FIG. 4. Referring to FIG. 9B, it can be seen that the directional acoustic sensor 200 according to the exemplary embodiment has an increased output, thereby improving sensitivity and reducing noise, compared to the frequency response characteristic of the directional acoustic sensor 100 shown in FIG. 9A. The signal-to-noise ratio of the directional acoustic sensor 200 according to the exemplary embodiment is measured to be approximately 51.6 dB. It can be seen that the signal-to-noise ratio of the directional acoustic sensor 200 according to the exemplary embodiment is improved by approximately 7 dB, compared to the frequency response characteristic of the directional acoustic sensor 100 shown in FIG. 9A.

[0074] As described above, in the directional acoustic sensor 200 according to the exemplary embodiment, the first and second resonators 230, 240 generate the first and second output signals 261, 262 of different polarities, and the signal processor 270 is used to take the difference between the first and second output signals 261, 262 of different polarities, thereby improving the signal-to-noise ratio (SNR). In addition, the first and second sensing elements 210, 220 are disposed adjacent to each other, thereby enabling the directional acoustic sensor 200 to be implemented in a small size.

[0075] FIG. 10 illustrates a directional acoustic sensor according to another exemplary embodiment.

[0076] 10, a directional acoustic sensor 300 includes first and second sensing elements 310 and 320 stacked in one direction, where the first sensing element 310 is the same as the first sensing element 210 shown in Fig. 4 but turned upside down, and the second sensing element 320 is the same as the second sensing element 220 shown in Fig. 4 but turned upside down. In Fig. 10, 311 and 321 denote first and second substrates, and 312 and 322 denote first and second supports.

[0077] The first resonator 330 provided on the first substrate 311 and the second resonator 340 provided on the second substrate 321 are disposed facing each other. Specifically, the first resonator 330 includes a first electrode 331 provided on the lower surface of the first support portion 312, a first piezoelectric layer 333 provided on the first electrode 331, and a second electrode 332 provided on the first piezoelectric layer 333. First and second terminals (not shown) electrically connected to the first and second electrodes 331, 332 are provided on the lower surface of the first substrate 311.

[0078] The second resonator 340 includes a third electrode 341 provided on the upper surface of the second support 322, a second piezoelectric layer 343 provided on the third electrode 341, and a fourth electrode 342 provided on the second piezoelectric layer 343. The third electrode 341 may have the same polarity as the first electrode 331, and the fourth electrode 342 may have the same polarity as the second electrode 332. Third and fourth terminals (not shown) electrically connected to the third and fourth electrodes 341 and 342 are provided on the upper surface of the second substrate 321. In this manner, the first and second resonators 330 and 340 are disposed opposite each other on the first and second support 312 and 322.

[0079] The first and second resonators 330 and 340 generate first and second output signals having opposite polarities and opposite phases, respectively, and a signal processor (not shown) takes the difference between the first and second output signals having opposite polarities to generate a final output signal, thereby improving the signal-to-noise ratio (SNR).

[0080] Fig. 11 is an exploded perspective view showing a directional acoustic sensor according to yet another exemplary embodiment, and Fig. 12 shows a cross section of the directional acoustic sensor shown in Fig. 11. 11 and 12, a directional acoustic sensor 400 includes first and second sensing elements 410 and 420 stacked in one direction, and a signal processor 470 that processes signals output from the first and second sensing elements 410 and 420.

[0081] The first sensing element 410 is similar to the first sensing element 210 shown in Fig. 4. In Fig. 11, 411, 411a, and 412 represent a first substrate, a first cavity, and a first support, and 431, 432, and 433 represent a first electrode, a second electrode, and a piezoelectric layer of the first resonator 430. And, 431a and 432a represent first and second terminals. Fig. 11 exemplarily illustrates a case where the first terminal 431a is located on the left side and the second terminal 432a is located on the right side on the upper surface of the first substrate 411 with respect to the +x-axis.

[0082] The second sensing element 420 provided under the first sensing element 410 is similar to the first sensing element 410, except that the polarity of the electrodes is reversed. The second sensing element 420 may be manufactured by connecting the electrode terminals of the first sensing element 410 in the opposite direction.

[0083] In FIG. 11, 421, 421a, and 422 represent the second substrate, the second cavity, and the second support. The second resonator 440 includes a third electrode 441 provided on the upper surface of the second support 422, a second piezoelectric layer 443 provided on the third electrode 441, and a fourth electrode 442 provided on the second piezoelectric layer 443. The first and second resonators 430, 440 are also arranged on the first and second support 412, 422 so as to face the same direction as each other. The third electrode 441 may have the same polarity as the second electrode 432, and the fourth electrode 442 may have the same polarity as the first electrode 431. For example, when the first and second electrodes 431, 432 are (+) and (-) electrodes, respectively, the third and fourth electrodes 441, 442 are (-) and (+) electrodes, respectively. Third and fourth terminals 441a, 442a electrically connected to the third and fourth electrodes 441, 442 are provided on the upper surface of the second substrate 421. Fig. 11 illustrates an example in which the third terminal 441a is located on the left side and the fourth terminal 442a is located on the right side on the upper surface of the second substrate 421 when viewed along the +x-axis.

[0084] In this embodiment, the first electrode 431 of the first resonator 430 and the fourth electrode 442 of the second resonator 440 are configured with the same polarity, and the second electrode 432 of the first resonator 430 and the third electrode 441 of the second resonator 440 are configured with the same polarity, so that the first and second resonators 430, 440 generate first and second output signals having opposite polarities and opposite phases through the first and second read circuits 451, 452, respectively, for the same input direction of external energy. Then, the signal processor 470 generates a final output signal by taking the difference between the first and second output signals of opposite polarities. As a result, the synchronized signal generated by the behavior of the first and second resonators 430, 440 is increased and the non-synchronized noise is reduced, thereby improving the signal-to-noise ratio (SNR).

[0085] Fig. 13 is an exploded perspective view showing a directional acoustic sensor according to yet another exemplary embodiment. The directional acoustic sensor 500 shown in Fig. 13 is similar to the directional acoustic sensor 400 shown in Fig. 11, except for the positions of the electrode terminals.

[0086] 13, the first sensing element 510 is similar to the first sensing element 410 shown in FIG. 11. The first and second terminals 431a', 432a' of the first sensing element 510 are located on the left and right sides, respectively, of the upper surface of the first substrate 411 when viewed from the +x-axis. The third and fourth terminals 441a', 442a' of the second sensing element 520 are located on the right and left sides, respectively, of the upper surface of the second substrate 421. Therefore, the second and third terminals 432a', 441a' having the same polarity are arranged along the same direction (e.g., the z-axis direction), and the first and fourth terminals 431a', 442a' having the same polarity are arranged along the same direction.

[0087] Fig. 14 is a perspective view showing a directional acoustic sensor according to yet another exemplary embodiment. Fig. 15A is a cross-sectional view taken along line III-III' in Fig. 14, and Fig. 15B is a cross-sectional view taken along line IV-IV' in Fig. 14. The directional acoustic sensor shown in Fig. 14 is similar to the directional acoustic sensor shown in Fig. 11, except that the first and second sensing elements are arranged on the same plane.

[0088] 14, 15A and 15B, the directional acoustic sensor 600 includes first and second sensing elements 610 and 620 arranged on the same plane, and a signal processor 670 for processing signals output from the first and second sensing elements 610 and 620. The first and second sensing elements 610 and 620 are arranged to be operable in synchronization with the input of external energy. The first and second sensing elements 610 and 620 are arranged to have a plane spacing of, for example, approximately 10 cm or less, more specifically, 0 cm to 1 cm, but this is merely exemplary. The first sensing element 610 is similar to the first sensing element 410 shown in FIG. 11. In FIG. 14, 611, 611a and 612 represent a first substrate, a first cavity and a first support, and 631, 632 and 633 represent a first electrode, a second electrode and a piezoelectric layer of the first resonator 630. And 631a, 632a represent first and second terminals.

[0089] The second sensing element 620 is provided adjacent to the first sensing element 610 on the same plane (for example, the xy plane). The second sensing element 620 is similar to the second sensing element 420 shown in FIG. 11. That is, the second sensing element 620 is similar to the first sensing element 610 except that the polarity of the electrodes is reversed. In FIG. 14, 621, 621a, and 622 represent a second substrate, a second cavity, and a second support, and 641, 642, and 643 represent a first electrode, a second electrode, and a piezoelectric layer of the second resonator 640. And, 641a and 642a represent first and second terminals. The second sensing element 620 may be manufactured by connecting the electrode terminals of the first sensing element 610 in the opposite direction. The first resonator 630 of the first sensing element 610 and the second resonator 640 of the second sensing element 620 may have the same center frequency.

[0090] The directional acoustic sensor 600 according to the present embodiment is realized by arranging the first and second sensing elements 410 and 420 of the directional acoustic sensor 400 shown in Fig. 11 on the same plane. Also, the directional acoustic sensor can be realized by arranging the first and second sensing elements 510 and 520 of the directional acoustic sensor 500 shown in Fig. 13 on the same plane.

[0091] Fig. 16 is a perspective view showing a directional acoustic sensor according to yet another exemplary embodiment. Fig. 17A is a cross-sectional view taken along line V-V' in Fig. 16, and Fig. 17B is a cross-sectional view taken along line VI-VI' in Fig. 16. The directional acoustic sensor 700 shown in Fig. 16 is similar to the directional acoustic sensor 600 shown in Fig. 14, except that the first and second sensing elements 710 and 720 are integrally provided.

[0092] 16, 17A and 17B, a directional acoustic sensor 700 includes first and second sensing elements 710, 720 integrally formed on the same plane, and a signal processor 770 that processes signals output from the first and second sensing elements 710, 720. The first and second sensing elements 710, 720 are arranged to be operable in synchronization with respect to an input of external energy.

[0093] A cavity 711a is formed penetrating the substrate 711, and first and second support portions 712, 713 extend from the substrate 711 toward the cavity 711a. The first sensing element 710 is provided on the first support portion 712, and the second sensing element 720 is provided on the second support portion 713.

[0094] The first sensing element 710 includes a first resonator 730, and the first resonator 730 includes a first electrode 731 provided on an upper surface of the first support part 712, a first piezoelectric layer 733 provided on the first electrode 731, and a second electrode 732 provided on the first piezoelectric layer 733. First and second terminals 731a and 732a electrically connected to the first and second electrodes 731 and 732 are provided on an upper surface of one side of the substrate 711.

[0095] The second sensing element 720 includes a second resonator 740, and the second resonator 740 includes a third electrode 741 provided on an upper surface of the second support portion 713, a second piezoelectric layer 743 provided on the third electrode 741, and a fourth electrode 742 provided on the second piezoelectric layer 743. The third electrode 741 may have the same polarity as the second electrode 732, and the fourth electrode 742 may have the same polarity as the first electrode 731. Third and fourth terminals 741a and 742a electrically connected to the third and fourth electrodes 741 and 742 are provided on the other upper surface of the substrate 711.

[0096] Fig. 18 is a perspective view showing a directional acoustic sensor according to yet another exemplary embodiment. The directional acoustic sensor 800 shown in Fig. 18 is similar to the directional acoustic sensor 700 shown in Fig. 16, except for the positions of the electrode terminals.

[0097] 18, a first sensing element 810 is similar to the first sensing element 710 shown in FIG 16. The first and second terminals 731a', 732a' of the first sensing element 810 are located on the right and left sides, respectively, of the upper surface of the left side of the substrate 711 when viewed from the +x-axis. And the third and fourth terminals 741a', 742a' of the second sensing element 820 are located on the right and left sides, respectively, of the upper surface of the right side of the substrate 711.

[0098] 19A to 19C are schematic diagrams of a conventional acoustic sensor and a directional acoustic sensor according to an exemplary embodiment as experimental models for a wake-up test, in which a side sound source SS and a front sound source FS are arranged around the acoustic sensor.

[0099] FIG. 19A shows a conventional acoustic sensor. In the acoustic sensor shown in FIG. 19A, two omnidirectional microphones 11 and 12 are arranged at a distance from each other, and directivity is realized by using the time difference between when signals reach the microphones 11 and 12. The distance between the omnidirectional microphones 11 and 12 is 5.6 cm, and the side sound source SS and the front sound source FS are each arranged at a position 1 m away from the center between the omnidirectional microphones 11 and 12. FIG. 19B and FIG. 19C show a directional acoustic sensor according to an exemplary embodiment. The directional acoustic sensor shown in FIG. 19B is similar to the directional acoustic sensor 600 shown in FIG. 14, and includes first and second sensing elements 21 and 22 arranged on the same plane. The distance between the first and second sensing elements 21 and 22 is 5.6 cm, and the side sound source SS and the front sound source FS are each arranged at a position 1 m away from the center between the first and second sensing elements 21 and 22. 19C is similar to the directional acoustic sensor 200 shown in Fig. 4, and includes first and second sensing elements 31, 32 stacked in the vertical direction. The distance between the first and second sensing elements 31, 32 is 3 mm, and the side sound source SS and the front sound source FS are disposed at positions 1 m away from the center between the first and second sensing elements 31, 32, respectively.

[0100] Figure 20 shows a comparison of the wake-up success rates of the acoustic sensors shown in Figures 19A to 19C. Figure 20 shows the results of a wake-up test using a trigger word for voice recognition from a front sound source FS in a situation where noise is generated from a side sound source SS. In Figure 20, "A" represents the acoustic sensor shown in Figure 19A, "B" represents the acoustic sensor shown in Figure 19B, and "C" represents the acoustic sensor shown in Figure 19C.

[0101] Referring to FIG. 20, it can be seen that the acoustic sensors according to the exemplary embodiments shown in FIGS. 19B and 19C have a higher wake-up success rate than the conventional acoustic sensor shown in FIG. 19A.

[0102] When using the acoustic sensor shown in Figures 19A to 19C to acquire a sound signal in the front direction in a situation where noise is generated from the side direction, the sensitivity ratio (specifically, the sensitivity ratio of the sound signal in the side direction to the sound signal in the front direction) was measured in order to evaluate the degree of influence of noise. As a result of the measurement in the frequency range of 100 Hz to 8 kHz, the sensitivity ratio was low at about 6 dB in the case of the conventional acoustic sensor shown in Figure 19A, but the sensitivity ratio was high at about 20 dB in the case of the acoustic sensor according to the exemplary embodiment shown in Figures 19B and 19C.

[0103] Fig. 21 is a perspective view showing a directional acoustic sensor according to yet another exemplary embodiment, and Fig. 22 is a cross-sectional view taken along line VII-VII' in Fig. 21.

[0104] 21 and 22, the directional acoustic sensor 900 includes a substrate 911 and a resonator 940 provided on the substrate 911. A cavity 911a is formed penetrating the substrate 911, and a support 912 is provided extending from the substrate 911 toward the cavity 911a. Here, one end of the support 912 is fixed to the substrate 911, and the other end is provided so as to move in the vertical direction (e.g., the z-axis direction). The substrate 911 is, for example, a silicon substrate, but is not limited thereto, and substrates made of various other materials may be used.

[0105] The resonator 940 is provided on one surface of the support portion 912. Specifically, the resonator 940 includes a first electrode 931 provided on the upper surface of the support portion 912, a first piezoelectric layer 934 provided on the first electrode 931, a second electrode 932 provided on the first piezoelectric layer 934, a second piezoelectric layer 935 provided on the second electrode 932, and a third electrode 933 provided on the second piezoelectric layer 935.

[0106] The second electrode 932 may be a common electrode. The third electrode 933 may have the same polarity as the first electrode 931. For example, the first, second and third electrodes 931, 932 and 933 are a (+) electrode, a (-) electrode and a (+) electrode, respectively. However, this is merely an example, and the first, second and third electrodes 931, 932 and 933 may be a (-) electrode, a (+) electrode and a (-) electrode, respectively. The first electrode 931, the first piezoelectric layer 934 and the second electrode 932 constitute a first resonator 941, and the second electrode 932, the second piezoelectric layer 935 and the third electrode 933 constitute a second resonator 942. The first and second resonators 941 and 942 may share the second electrode 932 as a common electrode.

[0107] First, second and third terminals 931a, 932a and 933a electrically connected to the first, second and third electrodes 931, 932 and 933 are provided on the upper surface of the substrate 911. Fig. 21 illustrates an example in which, with respect to the +x-axis, the first terminal 931a is located on the left side, the second terminal 932a is located in the middle and the third terminal 933a is located on the right side on the upper surface of the substrate 911.

[0108] When external energy such as sound or pressure is input to the resonator 940, electrical energy is generated. Specifically, when sound is input to the resonator 940, the first piezoelectric layer 934 of the first resonator 941 is deformed, and electrical energy is generated between the first and second electrodes 931 and 932, and the electrical energy is output as a first output signal through a first read circuit 951 connected to the first terminal 931a. Then, the second piezoelectric layer 935 of the second resonator 942 is deformed, and electrical energy is generated between the second and third electrodes 932 and 933, and the electrical energy is output as a second output signal through a second read circuit 952 connected to the third terminal 933a.

[0109] The first electrode 931 of the first resonator 941 and the third electrode 933 of the second resonator 942 are configured to have the same polarity, and the second electrode 932 is configured as a common electrode of a polarity different from that of the first and third electrodes 931 and 933, so that the first and second resonators 941 and 942 generate output signals of different polarities. Specifically, the first and second resonators 941 and 942 generate first and second output signals having opposite polarities and opposite phases.

[0110] The signal processor 970 performs arithmetic processing on the first output signal generated by the first resonator 941 and the second output signal generated by the second resonator 942 to generate a final output signal. Specifically, the signal processor 970 generates the final output signal by taking the difference between the first output signal and the second output signal of different polarities. This can improve the signal-to-noise ratio (SNR).

[0111] Fig. 23 shows a directional acoustic sensor according to yet another exemplary embodiment. The directional acoustic sensor 1100 shown in Fig. 23 differs from the directional acoustic sensor 900 shown in Fig. 22 in that a first resonator 1130 is provided on the upper surface of a substrate 1111, and a second resonator 1140 is provided on the lower surface of the substrate 1111.

[0112] 23, the first resonator 1130 includes a first electrode 1131 provided on an upper surface of a support 1112 of a substrate 1111, a first piezoelectric layer 1133 provided on the first electrode 1131, and a second electrode 1132 provided on the first piezoelectric layer 1133. First and second terminals (not shown) electrically connected to the first and second electrodes 1131 and 1132 are provided on the upper surface of the substrate 1111.

[0113] The second resonator 1140 includes a third electrode 1141 provided on the lower surface of the support 1112 of the substrate 1111, a second piezoelectric layer 1143 provided on the third electrode 1141, and a fourth electrode 1142 provided on the second piezoelectric layer 1143. Here, the third electrode 1141 may have the same polarity as the first electrode 1131, and the fourth electrode 1142 may have the same polarity as the second electrode 1132. Third and fourth terminals (not shown) electrically connected to the third and fourth electrodes 1141, 1142 are provided on the lower surface of the substrate 1111.

[0114] The first electrode 1131 of the first resonator 1130 and the third electrode 1141 of the second resonator 1140 are configured with the same polarity, and the second electrode 1132 of the first resonator 1130 and the fourth electrode 1142 of the second resonator 1140 are configured with the same polarity, so that the first and second resonators 1130 and 1140 generate output signals with different polarities. Then, a signal processor (not shown) generates a final output signal by taking the difference between the first output signal 261 and the second output signal 262 with different polarities. This can improve the signal-to-noise ratio (SNR).

[0115] Fig. 24 is an exploded perspective view showing a directional acoustic sensor according to yet another exemplary embodiment, and Fig. 25 is a block diagram showing a schematic configuration of the directional acoustic sensor shown in Fig. 24.

[0116] 24 and 25, the directional acoustic sensor 1200 includes first and second sensing elements 1210 and 1220, and a plurality of signal processors 1271, 1272, and 1273 for processing signals output from the first and second sensing elements 1210 and 1220. The first and second sensing elements 1210 and 1220 are stacked in one direction (e.g., the z-axis direction). Here, the first and second sensing elements 1210 and 1220 may be similar sensing elements, and in FIG. 24, the second sensing element 1220 is shown in the same form as the first sensing element 1210, but upside down.

[0117] The first sensing element 1210 includes a plurality of first resonators 1230a, 1230b, and 1230c provided on a first substrate 1211. A first cavity 1211a is formed penetrating the first substrate 1211, and a plurality of first support portions 1212a, 1212b, and 1212c are extended from the first substrate 1211 toward the first cavity 1211a.

[0118] The first resonators 1230a, 1230b, and 1230c may have different center frequencies. To this end, the first resonators 1230a, 1230b, and 1230c are provided to have different dimensions. For example, the first resonators 1230a, 1230b, and 1230c may have different lengths, different widths, and / or different thicknesses. FIG. 24 illustrates an example in which the first substrate 1211 is provided with a plurality of first support parts 1212a, 1212b, and 1212c having different lengths, and the first support parts 1212a, 1212b, and 1212c are provided with the first resonators 1230a, 1230b, and 1230c having different lengths. 24, three first resonators 1230a, 1230b, and 1230c having first, second, and third center frequencies are shown by way of example, however, this is merely an example and the number of first resonators 1230a, 1230b, and 1230c having different center frequencies may be modified in various ways.

[0119] Each of the multiple first resonators 1230a, 1230b, and 1230c is similar to the first resonator 230 shown in Fig. 4. Specifically, each of the first resonators 1230a, 1230b, and 1230c includes a first electrode (not shown) provided on the upper surface of the first support portion 1212a, 1212b, and 1212c, a first piezoelectric layer (not shown) provided on the first electrode, and a second electrode (not shown) provided on the first piezoelectric layer. Here, the first and second electrodes are, for example, a (+) electrode and a (-) electrode, respectively, but are not limited thereto.

[0120] A plurality of first terminals 1231a, 1231b, and 1231c electrically connected to the plurality of first electrodes and a plurality of second terminals 1232a, 1232b, and 1232c electrically connected to the second electrodes are provided on an upper surface of the first substrate 1211. The first sensing element 1210 may have bidirectionality, for example, bidirectionality in the z-axis direction.

[0121] The second sensing element 1220 is provided below the first sensing element 1210. As described above, the second sensing element 1220 may be an element in which the first sensing element 1210 is inverted. The second sensing element 1220 includes a plurality of second resonators 1240a, 1240b, and 1240c provided on a second substrate 1221. A second cavity 1221a is formed penetrating the second substrate 1221, and a plurality of second support portions 1222a, 1222b, and 1222c are extended from the second substrate 1221 toward the second cavity 1221a.

[0122] The second resonators 1240a, 1240b, and 1240c may have different center frequencies. Specifically, the second resonators 1240a, 1240b, and 1240c may have different center frequencies like the first resonators 1230a, 1230b, and 1230c described above. For this purpose, the second resonators 1240a, 1240b, and 1240c are provided to have different dimensions. FIG. 24 illustrates an example in which the second substrate 1221 is provided with a plurality of second support parts 1222a, 1222b, and 1222c having different lengths, and the second support parts 1222a, 1222b, and 1222c are provided with a plurality of second resonators 1240a, 1240b, and 1240c having the same length as the first resonators 1230a, 1230b, and 1230c. 24, three second resonators 1240a, 1240b, and 1240c having first, second, and third center frequencies are shown by way of example, however, this is merely an example, and the number of second resonators 1240a, 1240b, and 1240c having different center frequencies can be variously changed corresponding to the first resonators 1230a, 1230b, and 1230c.

[0123] Each of the second resonators 1240a, 1240b, and 1240c is similar to the second resonator 240 shown in FIG. 4. Specifically, each of the second resonators 1240a, 1240b, and 1240c includes a third electrode (not shown) provided on the lower surface of the second support portion 1222a, 1222b, and 1222c, a second piezoelectric layer (not shown) provided on the third electrode, and a fourth electrode (not shown) provided on the second piezoelectric layer. Here, the third electrode may have the same polarity as the first electrode, and the fourth electrode may have the same polarity as the second electrode. For example, when the first and second electrodes are (+) and (-) electrodes, respectively, the third and fourth electrodes are (+) and (-) electrodes, respectively.

[0124] A plurality of third terminals 1241a, 1241b, and 1241c electrically connected to the plurality of third electrodes and a plurality of fourth terminals 1242a, 1242b, and 1242c electrically connected to the fourth electrodes are provided on the lower surface of the second substrate 1221. The second sensing element 1220 may have the same directivity as the first sensing element 1210.

[0125] The first and second sensing elements 1210, 1220 are arranged to be operable in synchronization with the input of external energy. The first and second sensing elements 1210, 1220 are arranged, for example, at an interval of about 10 cm or less in the z-axis direction, more specifically, at an interval of 0 mm to 3 mm. However, this is merely an example, and the interval between the first and second sensing elements 1210, 1220 can be variously changed. In this way, the first and second sensing elements 1210, 1220 are arranged adjacent to each other, so that the directional acoustic sensor 1200 can be implemented in a small size.

[0126] A pair of first and second resonators 1230a, 1240a, 1230b, 1240b, 1230c, 1240c having the same center frequency constitutes one unit sensor. For example, the pair of first and second resonators 1230a, 1240a having a first center frequency constitutes a first unit sensor, the pair of first and second resonators 1230b, 1240b having a second center frequency constitutes a second unit sensor, and the pair of first and second resonators 1230c, 1240c having a third center frequency constitutes a third unit sensor.

[0127] When sound is input to the first resonators 1230a, 1230b, and 1230c, the first piezoelectric layer is deformed and electrical energy is generated between the first and second electrodes, and the electrical energy is output as a plurality of first output signals having different center frequencies via the first read circuits 1251a, 1251b, and 1251c. When sound is input to the second resonators 1240a, 1240b, and 1240c, the second piezoelectric layer is deformed and electrical energy is generated between the third and fourth electrodes, and the electrical energy is output as a plurality of second output signals having different center frequencies via the second read circuits 1252a, 1252b, and 1252c.

[0128] In this embodiment, the first electrode of each of the first resonators 1230a, 1230b, and 1230c and the third electrode of each of the second resonators 1240a, 1240b, and 1240c are configured with the same polarity, and the second electrode of each of the first resonators 1230a, 1230b, and 1230c and the fourth electrode of each of the second resonators 1240a, 1240b, and 1240c are configured with the same polarity, thereby generating output signals of different polarities.

[0129] For example, the pair of first and second resonators 1230a, 1240a in the first unit sensor have a first center frequency and generate first and second output signals having opposite phases and polarities. The pair of first and second resonators 1230b, 1240b in the second unit sensor have a second center frequency and generate first and second output signals having opposite phases and polarities. And the pair of first and second resonators 1230c, 1240c in the third unit sensor have a third center frequency and generate first and second output signals having opposite phases and polarities.

[0130] The multiple signal processors 1271, 1272, 1273 are provided corresponding to the multiple unit sensors. For example, the multiple signal processors 1271, 1272, 1273 include first, second, and third signal processors 1271, 1272, 1273 corresponding to the first, second, and third unit sensors.

[0131] The first signal processor 1271 generates a first final output signal 1281 by taking the difference between the first and second output signals of different polarities output from the first and second resonators 1230a, 1240a of the first unit sensor. The second signal processor 1272 generates a second final output signal 1282 by taking the difference between the first and second output signals of different polarities output from the first and second resonators 1230b, 1240b of the second unit sensor. And the third signal processor 1273 generates a third final output signal 1283 by taking the difference between the first and second output signals of different polarities output from the first and second resonators 1230c, 1240c of the third unit sensor. As a result, the first, second and third final output signals 1281, 1282, 1283 with improved signal-to-noise ratios are obtained.

[0132] FIG. 26 is a block diagram showing a modification of the directional acoustic sensor shown in FIG.

[0133] 26, the first sensing element 1210 combines signals output from the first resonators 1230a, 1230b, and 1230c through the first readout circuits 1251a, 1251b, and 1251c to generate a first output signal of the same polarity. Also, the second sensing element 1220 combines signals output from the second resonators 1240a, 1240b, and 1240c through the second readout circuits 1252a, 1252b, and 1252c to generate a second output signal of a different polarity from the first output signal. The signal processor 1270 can generate a final output signal 1280 by taking the difference between the first and second output signals of different polarities output from the first and second sensing elements 1210 and 1220.

[0134] FIG. 27 is a block diagram showing another modified example of the directional acoustic sensor shown in FIG.

[0135] 27, the first sensing element 1210 combines the outputs from the first resonators 1230a, 1230b, and 1230c into one output via a connection, and then generates a first output signal of the same polarity through a first read circuit 1251. Also, the second sensing element 1220 combines the outputs from the second resonators 1240a, 1240b, and 1240c into one output via a connection, and then generates a second output signal of a different polarity from the first output signal through a second read circuit 1252. The signal processor 1270 can generate a final output signal 1280 by taking a difference between the first and second output signals of different polarities output from the first and second sensing elements 1210 and 1220.

[0136] In the above, a case where each of the unit sensors has the same configuration as the first and second sensing elements 210, 220 shown in Fig. 4 has been described as an example. However, without being limited thereto, each of the unit sensors may have the same configuration as the first and second sensing elements 310, 320, 410, 420, 510, 520 shown in Figs. 10, 11, and 13. Also, while Fig. 24 shows an example where the first and second sensing elements 1210, 1220 are stacked along one direction (e.g., the z-axis direction), the first and second sensing elements 1210, 1220 may be provided on the same plane (e.g., the xy plane) as shown in Figs. 14, 16, and 18.

[0137] FIG. 28 is an exploded perspective view illustrating a directional acoustic sensor according to yet another exemplary embodiment.

[0138] 28, a directional acoustic sensor 1300 includes a substrate 1311, a plurality of resonators 1330a, 1330b, and 1330c provided on the substrate 1311, and a plurality of signal processors (not shown). A cavity 1311a is formed penetrating the substrate 1311, and a plurality of support portions 1312a, 1312b, and 1312c are extended from the substrate 1311 toward the cavity 1311a.

[0139] The multiple resonators 1330a, 1330b, and 1330c may have different center frequencies. To this end, the multiple resonators 1330a, 1330b, and 1330c are provided to have different dimensions. For example, the multiple resonators 1330a, 1330b, and 1330c may have different lengths, different widths, and / or different thicknesses. FIG. 28 exemplarily shows a case in which multiple support parts 1312a, 1312b, and 1312c having different lengths are provided on the substrate 1311, and multiple resonators 1330a, 1330b, and 1330c having different lengths are provided on the support parts 1312a, 1312b, and 1312c. FIG. 28 exemplarily shows three resonators 1330a, 1330b, and 1330c having first, second, and third center frequencies. However, this is merely an example, and the number of resonators 1330a, 1330b, 1330c having different center frequencies can be varied.

[0140] Each of the resonators 1330a, 1330b, and 1330c is similar to the resonator 940 shown in Fig. 21. Specifically, each of the resonators 1330a, 1330b, and 1330c includes a first electrode (not shown) provided on the upper surface of the support portion 1312a, 1312b, and 1312c, a first piezoelectric layer (not shown) provided on the first electrode, a second electrode (not shown) provided on the first piezoelectric layer, a second piezoelectric layer (not shown) provided on the second electrode, and a third electrode (not shown) provided on the second piezoelectric layer.

[0141] The second electrode may be a common electrode, and the third electrode may have the same polarity as the first electrode. For example, the first, second, and third electrodes are (+), (-), and (+), respectively. Thus, the first electrode, the first piezoelectric layer, and the second electrode form a first resonator, and the second electrode, the second piezoelectric layer, and the third electrode form a second resonator. On the upper surface of the substrate 1311, first terminals 1331a, 1331b, and 1331c electrically connected to the first electrodes, second terminals 1332a, 1332b, and 1332c electrically connected to the second electrodes, and third terminals 1333a, 1333b, and 1333c electrically connected to the third electrodes are provided.

[0142] A pair of first and second resonators having the same center frequency constitutes one unit sensor. For example, a resonator 1330a including a pair of first and second resonators having a first center frequency constitutes a first unit sensor, a resonator 1330b including a pair of first and second resonators having a second center frequency constitutes a second unit sensor, and a resonator 1330c including a pair of first and second resonators having a third center frequency constitutes a third unit sensor.

[0143] In this embodiment, a plurality of signal processors (not shown) corresponding to a plurality of unit sensors may be provided as shown in Fig. 25. For example, the plurality of signal processors include first, second and third signal processors corresponding to the first, second and third unit sensors.

[0144] Meanwhile, in this embodiment, one signal processor (not shown) may be provided as shown in Fig. 26. Also, in this embodiment, one signal processor (not shown) may be provided as shown in Fig. 27.

[0145] According to the above embodiment, the sensing elements generate output signals of different polarities, and the signal-to-noise ratio can be improved while maintaining the directionality by taking the difference between the output signals of different polarities thus generated. In addition, the sensing elements are arranged adjacent to each other, so that the directional acoustic sensor can be implemented in a small size. The above described embodiments are merely illustrative, and various modifications can be made by those skilled in the art. [Industrial Applicability]

[0146] The present invention is applicable, for example, to technical fields related to acoustic sensing. [Explanation of symbols]

[0147] 100, 200, 300, 400, 500, 600, 700, 800, 900, 1100, 1200, 1300 Directional Acoustic Sensor 111, 711, 911, 1111, 1311 board 111a, 711a, 911a, 1311a cavities 112, 912, 1112, 1312a, 1312b, 1312c Support part 130, 930, 1330a, 1330b, 1330c resonator 131, 231, 331, 431, 631, 731, 931, 1131 1st electrode 131a, 231a, 431a, 431a', 631a, 731a, 731a', 931a 1st terminal 132, 232, 332, 432, 632, 732, 932, 1132 2nd electrode 132a, 232a, 432a, 432a', 632a, 732a, 732a', 932a 2nd terminal 133 Piezoelectric Layer 150 Reading Circuit 160 Output Signal 210, 310, 410, 510, 610, 1210 First sensing element 211, 311, 411, 611, 1211 First board 211a, 411a, 611a, 1211a First cavity 212, 312, 412, 612, 712, 1212a, 1212b, 1212c 1st support part 220, 320, 420, 520, 620, 1220 Second sensing element 221, 321, 421, 621, 1221 Second board 221a, 421a, 621a, 1221a 2nd cavity 222, 322, 422, 622, 713, 1222a, 1222b, 1222c 2nd support part 230, 330, 430, 630, 730, 941, 1130, 1230a, 1230b, 1230c 1st resonator 233, 333, 433, 633, 733, 934, 1133 First piezoelectric layer 240, 340, 440, 640, 740, 942, 1140, 1240a, 1240b, 1240c 2nd resonator 241, 341, 441, 641, 741, 933, 1141 3rd electrode 241a, 441a, 441a', 641a, 741a, 741a', 933a, 1241a, 1241b, 1241c 3rd terminal 242, 342, 442, 642, 742, 1142 4th electrode 242a, 442a, 442a', 642a, 742a, 742a', 1242a, 1242b, 1242c 4th terminal 243, 343, 443, 643, 743, 935, 1143 Second piezoelectric layer 251, 451, 651, 751, 951, 1251a, 1251b, 1251c, 1251 First reading circuit 252, 452, 652, 752, 952, 1252a, 1252b, 1252c, 1252 Second reading circuit 261 First output signal 262 Second output signal 270, 470, 670, 770, 1270 Signal processor 280, 1280 Final output signal 1231a, 1231b, 1231c, 1331a, 1331b, 1331c 1st terminal 1232a, 1232b, 1232c, 1332a, 1332b, 1332c 2nd terminal 1271 First signal processor 1272 Second signal processor 1273 3rd signal processor 1281 1st final output signal 1282 2nd final output signal 1283 Third final output signal 1333a, 1333b, 1333c 3rd terminal

Claims

1. a first sensing element and a second sensing element each having different output gains according to an input direction of an external energy, and each generating at least one first output signal and at least one second output signal having different polarities for the same input direction; at least one signal process for taking a difference between the at least one first output signal and the at least one second output signal to generate at least one final output signal; the first sensing element is provided on a first substrate having a first cavity and includes at least one first resonator for generating the at least one first output signal; the second sensing element is provided on a second substrate having a second cavity and includes at least one second resonator for generating the at least one second output signal; At least one first support portion is extended from the first cavity, and at least one second support portion is extended from the second cavity, and at least one second resonator is provided on the first support portion. A directional acoustic sensor characterized in that one end of the first support portion is fixed to the first substrate, the other end of the first support portion is configured to move in an up-down direction within the first cavity, and one end of the second support portion is fixed to the second substrate, and the other end of the second support portion is configured to move in an up-down direction within the second cavity.

2. The directional acoustic sensor of claim 1 , wherein the first and second sensing elements have the same directionality.

3. The directional acoustic sensor of claim 1 , wherein the first and second sensing elements are stacked in one direction.

4. 4. The directional acoustic sensor according to claim 3, wherein the first support portion includes a first surface and a second surface that is an opposite surface to the first surface, and the second support portion includes a third surface that faces the second surface and a fourth surface that is an opposite surface to the third surface.

5. The directional acoustic sensor of claim 4, characterized in that the first resonator includes a first electrode provided on the first surface, a first piezoelectric layer provided on the first electrode, and a second electrode provided on the first piezoelectric layer, and the second resonator includes a third electrode provided on the fourth surface and having the same polarity as the first electrode, a second piezoelectric layer provided on the third electrode, and a fourth electrode provided on the second piezoelectric layer and having the same polarity as the second electrode.

6. 6. The directional acoustic sensor of claim 5, wherein the first substrate is provided with first and second terminals electrically connected to the first and second electrodes, and the second substrate is provided with third and fourth terminals electrically connected to the third and fourth electrodes.

7. The directional acoustic sensor of claim 4, characterized in that the first resonator includes a first electrode provided on the second surface, a first piezoelectric layer provided on the first electrode, and a second electrode provided on the first piezoelectric layer, and the second resonator includes a third electrode provided on the third surface and having the same polarity as the first electrode, a second piezoelectric layer provided on the third electrode, and a fourth electrode provided on the second piezoelectric layer and having the same polarity as the second electrode.

8. The directional acoustic sensor of claim 4, characterized in that the first resonator includes a first electrode provided on the first surface, a first piezoelectric layer provided on the first electrode, and a second electrode provided on the first piezoelectric layer, and the second resonator includes a third electrode provided on the third surface and having the same polarity as the second electrode, a second piezoelectric layer provided on the third electrode, and a fourth electrode provided on the second piezoelectric layer and having the same polarity as the first electrode.

9. The directional acoustic sensor of claim 1 , wherein the first and second sensing elements are disposed in the same plane.

10. The directional acoustic sensor of claim 9 , wherein the first and second substrates are integral with each other or spaced apart from each other.

11. 10. The directional acoustic sensor of claim 9, wherein the first resonator includes a first electrode provided on one surface of the first support portion, a first piezoelectric layer provided on the first electrode, and a second electrode provided on the first piezoelectric layer, and the second resonator includes a third electrode provided on one surface of the second support portion and having the same polarity as the second electrode, a second piezoelectric layer provided on the third electrode, and a fourth electrode provided on the second piezoelectric layer and having the same polarity as the first electrode.

12. The directional acoustic sensor according to any one of claims 1 to 11, characterized in that the first sensing element includes a plurality of first resonators that generate a plurality of first output signals having different center frequencies, and the second sensing element includes a plurality of second resonators that generate a plurality of second output signals having different center frequencies corresponding to the plurality of first resonators.

13. 13. The directional acoustic sensor of claim 12, wherein a pair of corresponding first and second resonators having the same center frequency generate first and second output signals of different polarities for the same input direction.

14. 14. The directional acoustic sensor of claim 13, wherein the at least one signal processor comprises a plurality of signal processors that take differences between the plurality of first output signals and the plurality of second output signals to generate a plurality of final output signals.

15. 14. The directional acoustic sensor of claim 13, wherein the at least one signal processor comprises a signal processor that takes a difference between the first output signals and the second output signals to generate a final output signal.

16. A semiconductor device comprising: a substrate having a cavity; At least one first resonator and at least one second resonator are laminated in one direction on the substrate, have different output gains depending on the input direction of external energy, and generate at least one first output signal and at least one second output signal having different polarities for the same input direction; at least one signal processor for taking a difference between the at least one first output signal and the at least one second output signal to generate at least one final output signal; At least one support portion is extended from the cavity, on which the at least one first resonator and the at least one second resonator are provided, A directional acoustic sensor, characterized in that one end of the support portion is fixed to the substrate, and the other end of the support portion is configured to move vertically within the cavity.

17. The directional acoustic sensor of claim 16, characterized in that the first resonator includes a first electrode provided on a first surface of the support portion, a first piezoelectric layer provided on the first electrode, and a second electrode provided on the first piezoelectric layer, and the second resonator includes the second electrode, a second piezoelectric layer provided on the second electrode, and a third electrode provided on the second piezoelectric layer and having the same polarity as the first electrode.

18. The directional acoustic sensor of claim 17 , wherein the first surface of the substrate is provided with first, second and third terminals electrically connected to the first, second and third electrodes.

19. The directional acoustic sensor of claim 16, characterized in that the first resonator includes a first electrode provided on a first surface of the support portion, a first piezoelectric layer provided on the first electrode, and a second electrode provided on the first piezoelectric layer, and the second resonator includes a third electrode provided on a second surface of the support portion and having the same polarity as the first electrode, a second piezoelectric layer provided on the third electrode, and a fourth electrode provided on the second piezoelectric layer and having the same polarity as the second electrode.

20. 20. The directional acoustic sensor of claim 19, wherein a first surface of the substrate is provided with first and second terminals electrically connected to the first and second electrodes, and a second surface of the substrate is provided with third and fourth terminals electrically connected to the third and fourth electrodes.

21. 17. The directional acoustic sensor of claim 16, wherein the at least one first resonator includes a plurality of first resonators generating a plurality of first output signals having different center frequencies, and the at least one second resonator includes a plurality of second resonators generating a plurality of second output signals having different center frequencies corresponding to the plurality of first resonators.

22. 22. The directional acoustic sensor of claim 21, wherein a pair of corresponding first and second resonators having the same center frequency generate first and second output signals of different polarities for the same input direction.

23. 23. The directional acoustic sensor of claim 22, wherein the at least one signal processor comprises a plurality of signal processors that perform a difference between the plurality of first output signals and the plurality of second output signals to generate a plurality of final output signals.

24. 23. The directional acoustic sensor of claim 22, wherein the at least one signal processor comprises a signal processor that performs a differential between the first output signals and the second output signals to generate a final output signal.

25. a first sensing element responsive to the same external acoustic input to generate a first output signal of a first polarity and a second sensing element responsive to the same external acoustic input to generate a second output signal of a polarity different from the first polarity; a signal processor that calculates a difference between the first output signal and the second output signal; the first sensing element includes a first resonator, and the second sensing element includes a second resonator; At least one of the first resonator and the second resonator is provided on a substrate having a cavity, a support portion on which at least one of the first resonator and the second resonator is provided is extended into the cavity of the substrate; An acoustic sensor, characterized in that one end of the support portion is fixed to the substrate, and the other end of the support portion is configured to move up and down within the cavity.

26. 26. The acoustic sensor of claim 25, wherein the first output signal and the second output signal have opposite phases to each other.

27. The acoustic sensor according to claim 25 or 26, wherein the first sensing element and the second sensing element are arranged to be stacked.

28. The acoustic sensor according to claim 25 or 26, wherein the first sensing element and the second sensing element are arranged on the same plane.

29. 27. The acoustic sensor of claim 25 or 26, wherein the first sensing element and the second sensing element are stacked and share a common electrode.

30. The acoustic sensor according to any one of claims 25 to 29, wherein the first and second sensing elements have the same directivity.

31. The acoustic sensor according to claim 25 , wherein the first resonator and the second resonator are disposed to face each other.

32. The acoustic sensor of claim 25 , wherein the first resonator and the second resonator are arranged to face in different directions.

33. The acoustic sensor according to any one of claims 25 to 32, wherein the first and second resonators have the same center frequency.

34. 34. The acoustic sensor according to claim 25, wherein each of the first and second resonators includes a pair of electrodes and a piezoelectric layer provided between the pair of electrodes.

35. The acoustic sensor according to any one of claims 25 to 34, characterized in that the first sensing element includes a plurality of first resonators having different center frequencies, and the second sensing element includes a plurality of second resonators having different center frequencies corresponding to the plurality of first resonators.

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