KR101833892B1 - Piezoelectric-mems high directional loudspeaker and beam steering method thereof - Google Patents

Abstract

Provided are a piezoelectric MEMS-based superdirectivity loudspeaker capable of accurately steering an acoustic wave beam by independently driving each transducer, and a beam steering method thereof. The beam steering method of a piezoelectric MEMS-based superdirectivity loudspeaker including a plurality of transducers comprises the steps of: reading a feature compensation parameter of each of the plurality of transducers from a memory; generating a driving signal on each of the plurality of transducers based on the feature compensation parameter; applying the driving signal to each of the plurality of transducers; and generating an ultrasonic wave by the plurality of transducers in response to the driving signal.

Description

TECHNICAL FIELD [0001] The present invention relates to a piezoelectric MEMS-based super-directional loudspeaker and a beam steering method thereof,

The present invention relates to a piezoelectric MEMS-based super-directional loudspeaker and a beam steering method thereof, and more particularly, to a piezoelectric MEMS-based super-directional loudspeaker using a parametric array and a beam steering method thereof.

A parametric array means that when a high frequency acoustic signal is strongly generated, a low-frequency acoustic signal having a high directivity in only a specific direction is produced by the nonlinear acoustic transfer phenomenon of the medium.

In general, the higher the frequency of a sound signal (for example, an ultrasonic wave) or the larger the size of a device (transducer) for generating an acoustic signal, the higher the directionality. In the case of audible sound (20 Hz to 20 kHz), the sound is transmitted in all directions unless the transducer is very large (because the directionality is not sufficiently high).

However, when the parametric array phenomenon is realized in the air, it becomes possible to transmit the audible sound only in a specific direction by using a small-sized transducer. This is called parametric array phenomenon in air, and research and development on a loudspeaker using a parametric array in air is underway.

The present invention provides a piezoelectric MEMS-based super-directional loudspeaker capable of independently driving each transducer and capable of precisely steering a sound beam, and a beam steering method thereof.

According to another aspect of the present invention, there is provided a method of steering a piezoelectric MEMS-based supergain loudspeaker including a plurality of transducers for generating ultrasonic waves, Generating a drive signal for each of the plurality of transducers based on the characteristic compensation parameter, applying the drive signal to each of the plurality of transducers, And generating ultrasonic waves corresponding to the driving signals.

The characteristic compensation parameter may be obtained by measuring an output of each of the plurality of transducers while applying the same reference voltage to the plurality of transducers.

Wherein the step of generating the drive signal comprises the steps of modulating an input signal with the drive signal corresponding to each of the plurality of transducers using a carrier signal, and modulating a plurality of power amplifiers And amplifying the drive signal applied to each of the plurality of transducers.

The step of generating the drive signal may further comprise adjusting a phase of the drive signal applied to each of the plurality of transducers based on the characteristic compensation parameter corresponding to each of the plurality of transducers .

The amplifying may further include adjusting amplification gains of the plurality of power amplifiers based on the characteristic compensation parameters corresponding to each of the plurality of transducers.

Wherein the plurality of transducers include two or more kinds of transducers having different sizes, and the modulating step includes a step of modulating the input signal with the drive signal according to the type of each of the plurality of transducers And selecting the carrier signal differently.

The generating of the ultrasonic waves may include generating ultrasonic waves of different frequencies according to the types of the plurality of transducers.

In accordance with another aspect of the present invention, there is provided a piezoelectric MEMS-based supergain loudspeaker comprising: a plurality of transducers for generating ultrasonic waves; and a plurality of transducers connected in parallel to the plurality of transducers for modulating and amplifying input signals, And a plurality of integrated circuits outputting to a corresponding one of the transducers, wherein each of the plurality of integrated circuits modulates the input signal into a driving signal of a corresponding transducer of the plurality of transducers using a carrier wave A signal processor, and a power amplifier for amplifying the driving signal and applying the amplified driving signal to a corresponding transducer of the plurality of transducers.

Each of said plurality of integrated circuits further comprising a memory for storing characteristic compensation parameters of a corresponding transducer of said plurality of transducers, each of said plurality of integrated circuits comprising: The phase or amplification gain of the driving signal applied to the corresponding transducer in the ducer can be adjusted.

Wherein the piezoelectric MEMS-based supergain loudspeaker comprises a substrate on which the plurality of transducers are located, a plurality of recesses on which the plurality of integrated circuits are mounted and each of the plurality of transducers is received, A first wiring part connected to each of the plurality of transducers and located on the substrate, and a second wiring part connected to each of the plurality of transducers through a plurality of via holes formed in the protective substrate, And a second wiring portion connecting the plurality of integrated circuits.

The substrate may be composed of a first silicon layer, a multilayer film of an etch stop film and a second silicon layer, and the first silicon layer may include a plurality of openings corresponding to each of the plurality of transducers.

Wherein each of the plurality of transducers comprises a multilayer film of a first electrode, a piezoelectric layer, and a second electrode, the first wiring portion includes a plurality of first lower wiring connected to the first electrode of each of the plurality of transducers, And a plurality of second lower wirings connected to the second electrode of each of the transducers.

The first lower wiring includes a first connector in contact with the first electrode and a first extension extending from the first connector, and the second lower wiring includes an air bridge type A second connector of the second connector, and a second extension extending from the second connector.

Each of the plurality of recesses accommodates the transducer, the first connector, and the second connector, wherein the plurality of via holes include a first via hole overlapping the first extension portion, And may include an overlapping second via hole.

The second wiring portion may include a first upper wiring connected to the first lower wiring through the first via hole and a second upper wiring connected to the second lower wiring through the second via hole .

The plurality of integrated circuits may be connected to any one of the first upper wiring and the second upper wiring.

The plurality of transducers may include two or more types of transducers having different sizes, and the two or more types of transducers may generate ultrasonic waves of different frequencies.

According to the present embodiment, it is possible to provide a piezoelectric MEMS-based super-directional loudspeaker capable of independently driving each transducer and precisely steering an acoustic wave beam, and a beam steering method thereof.

1 is a partial cross-sectional view of a piezoelectric MEMS-based supergain loudspeaker according to an embodiment of the present invention.
2 is a partial plan view of a piezoelectric MEMS-based supergain loudspeaker according to an embodiment of the present invention.
3 is a partial plan view of a transducer array of a piezoelectric MEMS based supergain loudspeaker in accordance with an embodiment of the present invention.
4 is a block diagram of a transducer array of a piezoelectric MEMS-based supergain loudspeaker according to an embodiment of the present invention.
5 is a schematic structural view of a piezoelectric MEMS-based supergain loudspeaker according to an embodiment of the present invention.
6 is a schematic view illustrating an integrated circuit of a piezoelectric MEMS-based supergain loudspeaker according to an embodiment of the present invention.
FIG. 7 is a schematic view illustrating a method of steering a piezoelectric MEMS-based supergain loudspeaker according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

When an element such as a layer, a film, an area, a plate, or the like is referred to as being "on" another element throughout the specification, it includes not only the element "directly above" another element but also the element having another element in the middle. And "above" means located above or below the object portion, and does not necessarily mean that the object is located on the upper side with respect to the gravitational direction.

When an element is referred to as "including" an element throughout the specification, it means that the element may further include other elements unless specifically stated otherwise. The sizes and thicknesses of the respective components shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not limited to the illustrated ones.

FIG. 1 is a cross-sectional view of a piezoelectric MEMS-based supergain loudspeaker (hereinafter referred to as 'loudspeaker') using a parametric array according to an embodiment of the present invention, FIG. 2 is a plan view of the loudspeaker shown in FIG. 1 And Fig. 3 is a plan view of the transducer array of the loudspeaker shown in Fig.

1 to 3, a loudspeaker 100 according to an embodiment includes a substrate 10, a transducer array 40 located on the substrate 10, and a transducer array 40 that protects the transducer array 40 A protection substrate 50, and integrated circuits (ICs) mounted on the protection substrate 50. [

The substrate 10 may be a silicon wafer or a silicon-on-insulator (SOI) wafer having an oxide film embedded therein. In the latter case, the substrate 10 includes a first silicon layer 11, an oxide film 12 located on the first silicon layer 11, a second silicon layer 13 located on the oxide film 12, . ≪ / RTI > The oxide film 12 functions as an etch stop film, and the first silicon layer 11 has a larger thickness than the second silicon layer 13. [

In the first silicon layer 11, a plurality of openings 14 corresponding to each of the plurality of transducers 20 is located. The portions corresponding to each of the plurality of transducers 20 in the substrate 10 due to the plurality of openings 14 can form a thin film structure.

The transducer array 40 includes a plurality of transducers 20 positioned on the second silicon layer 13 and spaced apart from each other by a distance therebetween and a plurality of transducers 20 electrically connected to the plurality of transducers 20, (30).

The transducer 20 is made of a piezoelectric thin film type ultrasonic transducer manufactured by MEMS (micro electro mechanical system). More specifically, the transducer 20 includes a first electrode 21, a piezoelectric layer 22 positioned on the first electrode 21, and a second electrode 23 located on the piezoelectric layer 22 .

The piezoelectric layer 22 may comprise a lead zirconate titanate (PZT) or a PLZT in which a portion of the PZT is replaced with lanthanum (La). The opening 14 of the transducer 20 and the first silicon layer 11 may be formed in a circular shape and the width (diameter) of the opening 14 may be greater than the width (diameter) of the transducer 20 .

The first wiring portion 30 includes a first lower wiring 31 electrically connected to the first electrode 21 and a second lower wiring 35 electrically connected to the second electrode 23. The first lower wiring 31 may include a first connector 32 in contact with the first electrode 21 and a first extension 33 formed in an arc shape at one side of the transducer 20. The second lower wiring 35 may include a second connector 36 in contact with the second electrode 23 and a second extension 37 formed in an arc shape on the other side of the transducer 20.

At this time, the second connector 36 may exist in the form of an air bridge floating on the substrate 10 so as not to be energized with the first electrode 21. The second connector 36 in the form of an air bridge may be formed using photoresist. The first electrode 21 and the first connector 32 may be formed of the same material at the same time.

The protective substrate 50 may be a silicon wafer and is fixed on the substrate 10 to protect the transducer array 40. A plurality of recesses 55 corresponding to each of the plurality of transducers 20 is located on one surface of the protective substrate 50 facing the substrate 10. The recess 55 may be circular and may be sized to receive the transducer 20, the first connector 32, and the second connector 36. The width (diameter) of the concave portion 55 may be larger than the width (diameter) of the opening portion 14.

A plurality of via holes (51, 52) are located on the protection substrate (50). The plurality of via holes 51 and 52 are connected to the first via hole 51 overlapping the first extension portion 33 of the first lower wiring 31 and the second via hole 51 of the second lower wiring 35 37 and a second via hole 52 overlapping the second via hole. The second wiring portion 60 is located on the protection substrate 50 and is electrically connected to the first wiring portion 30 through a plurality of via holes 51 and 52 formed in the protection substrate 50.

Specifically, the second wiring portion 60 includes a first upper wiring 61 electrically connected to the first lower wiring 31 through the first via hole 51, and a second upper wiring 61 through the second via hole 52 And a second upper wiring (62) electrically connected to the second lower wiring (35).

Integrated circuits (IC) 70 for signal processing are located on the protection substrate 50. The integrated circuit 70 may be a CMOS specific application specific integrated circuit (ASIC). The integrated circuit 70 is electrically connected to either the first upper wiring 61 or the second upper wiring 62. In the drawing, the integrated circuit 70 is connected to the first upper wiring 61, but the opposite case is also possible.

When the integrated circuit 70 is connected to the first upper wiring 61, signals processed in the integrated circuit 70 are transmitted through the first upper wiring 61 and the first lower wiring 31 to the transducer 20, The first electrode 21 functions as a signal electrode, and the first electrode 21 functions as a signal electrode. The second electrode 23 of the transducer 20 is grounded through the second lower wiring 35 and the second upper wiring 62 to function as a ground electrode.

When the integrated circuit 70 is connected to the second upper wiring 62, signals processed in the integrated circuit 70 are transmitted through the second upper wiring 62 and the second lower wiring 35 to the transducer 20, And the second electrode 23 functions as a signal electrode. The first electrode 21 of the transducer 20 is grounded through the first lower wiring 31 and the first upper wiring 61 to function as a ground electrode.

When an electric signal is applied to the transducer 20, the transducer 20 generates ultrasonic waves, and the generated ultrasonic waves travel in a specific direction by a parametric array phenomenon in the medium while moving the medium (for example, air) (Highly directional) audible sound. More than 100 transducers 20 can be disposed on one substrate 10 (for example, a 6-inch semiconductor wafer), and a plurality of substrates 10 can be combined to constitute the loudspeaker 100.

The plurality of transducers 20 may include two or more kinds of transducers having different sizes. The two transducers 20 of different sizes generate ultrasonic waves of different frequencies. Although two types of transducers 20 are shown in FIGS. 2 and 3, three or more transducers may be used.

Fig. 4 is a configuration diagram showing a plurality of transducer arrays among the loudspeakers shown in Fig. 1. Fig.

4, the transducer array 40 includes a first transducer array 41 having a first diameter D1 and a second transducer array 41 having a second diameter D2 that is smaller than the first diameter D1. And a ducer array 42. The first transducer array 41 may be an odd row and the second transducer array 42 may be an even row.

The first transducer array 41 can generate ultrasonic waves with a frequency f1 of 100 kHz for example and the second transducer array 42 can generate ultrasonic waves with a frequency f2 at a frequency of for example 110 kHz have. In this case, in addition to the signals f1 and f2 directly generated by the first and second transducer arrays 41 and 42 due to the nonlinear acoustic transfer phenomenon of the medium, a frequency of 200 kHz which is twice as high as f1, 220 kHz which is twice as high as f2, A total of 210 kHz, and a difference (fd) between f1 and f2 (10 kHz). At this time, when the difference frequency fd is sufficiently smaller than f1 and f2, the frequency signals of relatively high frequency signals f1, f2, 2f1, 2f2 and f2 + f1 disappear rapidly due to the high attenuation effect, (fd) are transmitted to far away. At this time, the acoustic signal of fd (10 kHz) maintains the high directionality of 100 kHz and 110 kHz ultrasonic waves generated in the transducer array 40, so that the acoustic signal of low frequency but high directionality is obtained. This is a parametric array phenomenon. The transducer 20 using the parametric array phenomenon has an advantage that a high directivity sound wave can be generated at a low frequency.

Referring again to Figures 1 to 3, the loudspeaker 100 of the present embodiment mechanically protects the transducer array 40 using a protective substrate 50. The thin film transducer 20 and the second connector 36 in the form of an air bridge are mechanically very fragile so that the protective substrate 50 surrounds them and blocks them from the outside. Therefore, the loudspeaker 100 can effectively prevent damage to the transducer 20 and the second connector 36 due to an external impact.

Also, the loudspeaker 100 of the present embodiment can overcome the spatial limitations. Assuming that there is no protective substrate 50, the degree of integration of the transducer 20 is reduced because both the transducer 20, the integrated circuit 70, and the wiring portion must be disposed on the substrate 10. However, the loudspeaker 100 of this embodiment can increase the degree of integration of the transducer 20 by the three-dimensional connection structure, and as a result, improve the acoustic performance.

In addition, the loudspeaker 100 of the present embodiment can arrange the transducers 20 and the integrated circuits 70 in a one-to-one correspondence by a three-dimensional connection structure. Thus, independent driving of each transducer 20 is possible, and the steering precision of the sonic beam can be improved.

In addition, the loudspeaker 100 of this embodiment can reduce the wiring resistance due to shortening of the wiring length. Therefore, it is possible to increase the energy efficiency by reducing the power consumption and increase the limiting current amount for the maximum volume. The loudspeaker 100 of the present embodiment is a one-chip type speaker in which the transducer 20 and the integrated circuit 70 are integrated. The loudspeaker 100 is a mobile device such as a smart phone and a lab-top computer, The present invention can be easily applied to a wearable apparatus of the present invention.

Figure 5 shows a schematic block diagram of the loudspeaker of Figure 1;

Referring to FIG. 5, a loudspeaker 100 according to an embodiment may include a plurality of integrated circuits 70 and a plurality of transducers 20.

The plurality of integrated circuits 70 may be connected in a one-to-one relationship with the plurality of transducers 20. That is, the plurality of integrated circuits 70 may be connected to different transducers 20, respectively.

Each integrated circuit 70 generates a driving signal for generating ultrasonic waves and outputs the driving signal to the corresponding transducer 20.

Each of the transducers 20 can generate ultrasonic waves by converting a driving signal (electric signal) from a corresponding integrated circuit 70 into a mechanical vibration. The transducer 20 is a multi-layered structure formed on a thin substrate, and can generate ultrasonic waves by vibrating in the up and down directions when a driving signal is applied.

The plurality of transducers 20 may be divided into first and second transducer arrays 41 and 42. In order to generate a high directional sound wave at a low frequency through the parametric array phenomenon, the first and second transducer arrays 41 and 42 can generate ultrasonic waves of different frequencies.

In order for the first and second transducer arrays 41 and 42 to generate ultrasonic waves of different frequencies, the driving signals for driving the first and second transducer arrays 41 and 42 must have different frequency components do.

Thus, each integrated circuit 70 can generate a drive signal having different frequency components depending on which transducer array it is connected to. That is, the integrated circuits 70 connected to the first transducer array 41 and the integrated circuits 70 connected to the second transducer array 42 can generate drive signals having different frequency components have. For example, the integrated circuits 70 connected to the first transducer array 41 generate driving signals having a frequency component of 100 kHz, and the integrated circuits 70 connected to the second transducer array 42 A driving signal having a frequency component of 110 kHz can be generated.

Fig. 6 is a schematic view showing the integrated circuit of Fig. 5; Fig.

Referring to FIG. 6, each of the plurality of integrated circuits 70 may include a signal processor 71, a power amplifier 72, and a memory 73.

When the input signal is input, the signal processor 71 can modulate the input signal into a driving signal using the corresponding carrier signal and output it. The frequency component of the drive signal generated by each integrated circuit 70 can be determined by the frequency of the carrier signal used for modulation. For example, in order for a drive signal generated by the integrated circuit 70 to have a frequency component of 100 kHz, a carrier signal of 100 kHz is used for signal modulation and a drive signal generated by the integrated circuit 70 uses a frequency component of 110 kHz A carrier signal of 110 kHz can be used to modulate the signal.

The power amplifier 72 can amplify the drive signal modulated by the signal processor 71 and apply the amplified drive signal to the corresponding transducer 20.

The memory 73 may store the characteristic compensation parameters of the corresponding transducers 20. [

The electrical characteristics of all the transducers 20 can not be the same due to the characteristics of the MEMS manufacturing method. For example, even if the same drive signal is applied, the intensity (or decibel) of the acoustic signal output according to the transducer 20, the vibration speed, and the like may be different from each other. The electrical characteristic deviation between the transducers 20 can cause a deviation in output between the transducers 20, thereby reducing the beam steering accuracy.

The loudspeaker 100 of this embodiment stores the characteristic compensation parameters for compensating the electrical characteristic deviation of each transducer 20 in the memory 73 and the signal processor 71 and the power amplifier 72 It is possible to perform the deviation compensation on the drive signal based on the characteristic compensation parameter stored in the memory 73 when generating the drive signal. Further, for example, the signal processor 71 can adjust the phase of the driving signal of the corresponding transducer 20 based on the characteristic compensation parameter stored in the memory 73. [ Further, for example, the power amplifier 72 can adjust the amplification gain of the driving signal of the corresponding transducer 20 based on the characteristic compensation parameter stored in the memory 73. [

The characteristic compensation parameters of each transducer 20 are set such that the same reference voltage is applied to all the transducers 20 and the acoustic wave (or acoustic wave) output by each transducer 20 through the measurement equipment (not shown) Signal) and the oscillation speed of the signal.

6 shows an example in which each integrated circuit 70 includes the signal processor 71, the power amplifier 72, and the memory 73. However, the present invention is not limited thereto, According to the example, the integrated circuit 70 may be implemented to include more or fewer components. For example, the integrated circuit of another embodiment may further include a digital-to-analog converter (DAC). In this case, the input signal input to each integrated circuit is a digital signal, and the DAC can convert the input signal into an analog signal and output it to the signal processor. Further, the integrated circuit of another embodiment may not include a memory. In this case, the characteristic compensation parameters of each transducer 20 can be stored in a memory outside the integrated circuit.

Fig. 7 schematically shows a method of beam steering of the loudspeaker of Fig. 5;

Referring to FIG. 7, a characteristic compensation parameter for each of the plurality of transducers 20 constituting the loudspeaker 100 of the present embodiment is obtained through a calibration process (S100). In this manner, the characteristic compensation parameters of each transducer 20 obtained through the calibration process are stored in the memory 73 in the corresponding integrated circuit 70 (S110).

In step S100, the measuring instrument (not shown) applies the same reference voltage to all the transducers 20 constituting the loudspeaker 100, and applies the same reference voltage to each transducer 20 Measure the output. For example, the measuring instrument can measure the intensity and vibration speed of a sound wave (or an acoustic signal) generated by each transducer 20 while a reference voltage is applied to each transducer 20. The measuring instrument can generate the characteristic compensation parameter for compensating the electrical characteristic deviation of the transducers 20 based on the output of each transducer 20 when the reference voltage is applied.

The integrated circuit 70 reads the characteristic compensation parameters from the memory 73 in step S130 and outputs the characteristic compensation parameters to the corresponding transducers 20 based on the read characteristic compensation parameters (S140).

In step S140, each integrated circuit 70 can modulate an input signal into a driving signal through the signal processor 71. [ In this process, the frequency of the carrier signal used for signal modulation in each integrated circuit 70 may vary depending on the type of the corresponding transducer 20. That is, the frequency of the carrier signal used for signal modulation may vary according to the frequency of the ultrasonic wave to be output through the corresponding transducer 20.

For example, the integrated circuit 70 connected to the first transducer array 41 for generating ultrasonic waves of 100 kHz frequency f1 can use a carrier signal of 100 kHz frequency f1 for modulation of the input signal. Also, for example, an integrated circuit 70 coupled to a second transducer array 42 that generates ultrasonic waves at 110 kHz frequency f2 can use a carrier signal at a frequency of 110 kHz (f2) for modulation of the input signal have.

In operation S 140, the driving signal modulated by the signal processor 71 may be amplified by the power amplifier 72.

In step S140, each integrated circuit 70 adjusts the amplification gain and phase of the drive signal based on the characteristic compensation parameters stored in the memory 73 in the process of generating the drive signal, so that the corresponding transducers 20 ) Can be compensated for.

Each of the integrated circuits 70 applies a driving signal to the corresponding transducer 20 in operation S150. Each of the integrated transducers 20 vibrates in the up / down direction to generate a driving signal corresponding to the driving signal Thereby generating ultrasonic waves (S160).

According to the prior art, a directional beam steering system using a parametric array is implemented in a two-dimensional array structure in which wires for applying driving signals to the first and second wires of the transducer are formed on the same layer. In such a two-dimensional array structure, it is very difficult to form wirings for applying a driving signal without interfering with the arrangement structure of the transducer array. Accordingly, in the two-dimensional array structure, a method of grouping a plurality of transducers into one channel and applying a driving signal to each channel has been used.

When a driving signal is applied to each channel, it is impossible to independently drive each transducer, which may act as a factor to lower the beam steering precision. Normally, the electrical characteristics of all the transducers can not be equal to each other due to the characteristics of the MEMS manufacturing method. Further, when a driving signal is supplied to a plurality of transducers by using one amplifier, the wiring lengths between the amplifiers are different from each other depending on the position of the transducers, thereby causing a variation in wiring resistance between each transducer and the amplifier do. This wiring resistance variation can cause a difference between driving signals received by each transducer even if the amplifier outputs the same driving signal, and the wiring resistance variation further increases as the connection wiring length between the amplifier and the transducers becomes longer.

Therefore, when a driving signal is applied to each channel, it is difficult to generate a desired output due to a difference in electrical characteristics and wiring resistance between transducers constituting one channel. As a result, the beam steering accuracy is lowered.

The loudspeaker 100 of the present embodiment can realize the connection of the transducers 20 and the integrated circuits 70 in a one-to-one correspondence by implementing the transducer 20 in a three-dimensional connection structure. Thus, independent driving of each transducer 20 is possible, and the phase of the driving signal, the amplification gain (or the weighting factor), and the like can be precisely adjusted in accordance with the electrical characteristics of each transducer 20 It is possible to improve the beam steering precision by compensating for the characteristic deviation between the transducers 20. In addition, the deviation of the wiring length between the power amplifier 72 and each transducer 20 is minimized, and the wiring length is also reduced, thereby ensuring the precision of the driving signal.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course.

100: loudspeaker 10: substrate
11: first silicon layer 12: oxide film
13: second silicon layer 20: transducer
21: first electrode 22: piezoelectric layer
23: second electrode 30: first wiring portion
31: first lower wiring 35: second lower wiring
40: transducer array 41: first transducer array
42: second transducer array 50: protective substrate
51: first via hole 52: second via hole
55: concave portion 60: second wiring portion
61: first upper wiring 62: second upper wiring
70: integrated circuit 71: signal processor
72: power amplifier 73: memory

Claims (17)

delete delete delete delete delete delete delete A plurality of transducers for generating ultrasonic waves, and
A plurality of integrated circuits connected in one-to-one relation to the plurality of transducers, for modulating and amplifying input signals and outputting the amplified signals to a corresponding transducer of the plurality of transducers,
Each of the plurality of integrated circuits includes:
A memory for storing characteristic compensation parameters of a corresponding transducer among the plurality of transducers,
A signal processor for modulating the input signal with a driving signal of a corresponding transducer of the plurality of transducers using a carrier wave,
And a power amplifier amplifying the driving signal and applying the amplified driving signal to a corresponding transducer of the plurality of transducers,
Each of the plurality of integrated circuits performs deviation compensation for the drive signal output to the corresponding transducer among the plurality of transducers based on the characteristic compensation parameter of the corresponding one of the plurality of transducers Piezoelectric MEMS based super directional loudspeaker. 9. The method of claim 8,
Wherein the signal processor adjusts the phase of the drive signal based on the characteristic compensation parameter,
Wherein the power amplifier adjusts amplification gain of the drive signal based on the characteristic compensation parameter. 9. The method of claim 8,
A substrate on which the plurality of transducers are located,
A protective substrate mounted on the plurality of integrated circuits and including a plurality of recesses for receiving the plurality of transducers, the protective substrate coupled to the substrate to protect the plurality of transducers,
A first wiring part located on the substrate and connected to each of the plurality of transducers,
And a second wiring portion connecting the first wiring portion and the plurality of integrated circuits through a plurality of via holes formed in the protection substrate,
A piezoelectric MEMS-based super-directional loudspeaker. 11. The method of claim 10,
Wherein the substrate is composed of a first silicon layer, a multilayer film of an etch stop film and a second silicon layer,
Wherein the first silicon layer comprises a plurality of openings corresponding to each of the plurality of transducers. 11. The method of claim 10,
Wherein each of the plurality of transducers comprises a multilayer film of a first electrode, a piezoelectric layer and a second electrode,
Wherein the first wiring portion comprises a plurality of first lower wiring connected to the first electrode of each of the plurality of transducers and a plurality of second lower wiring connected to the second electrode of each of the plurality of transducers, Directional loudspeaker. 13. The method of claim 12,
The first lower wiring includes a first connector in contact with the first electrode and a first extension extending from the first connector,
Wherein the second lower wiring comprises a second connector in the form of an air bridge in contact with the second electrode and a second extension extending from the second connector. 14. The method of claim 13,
Each of the plurality of recesses receiving the transducer, the first connector, and the second connector,
Wherein the plurality of via holes include a first via hole overlapping with the first extending portion and a second via hole overlapping with the second extending portion. 15. The method of claim 14,
The second wiring portion includes a first upper wiring connected to the first lower wiring through the first via hole and a second upper wiring connected to the second lower wiring through the second via hole, Based super directional loudspeaker. 16. The method of claim 15,
Wherein the plurality of integrated circuits are connected to either the first upper wiring and the second upper wiring. 9. The method of claim 8,
Wherein the plurality of transducers comprise:
A plurality of first transducers for generating ultrasonic waves of a first frequency, and
And a plurality of second transducers generating ultrasonic waves of a second frequency different from the first frequency and having different sizes from the plurality of second transducers.

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