TWI839910B - Acoustic coupler - Google Patents

Abstract

The invention provides an acoustic coupler, which includes a signal modulation unit, a sound wave transmitting unit, a sound wave receiving unit, a signal demodulation unit and a package material. The signal modulation unit is used for modulating an input signal into a driving signal; the sound wave transmitting unit transmits a sound wave according to the driving signal; the sound wave receiving unit is used for receiving the sound wave to generate a sensing signal; the signal demodulation unit demodulates the sensing signal into an output signal, and the output signal and the input signal have the same waveform phase; the package material at least covers the sound wave receiving unit and the sound wave transmitting unit, so that the sound wave receiving unit and the sound wave transmitting unit are electrically isolated at least by the package material. The sound wave emitted from the sound wave receiving unit is transmitted obliquely in the package material, and is transmitted obliquely to the sound wave receiving unit after being reflected at an interface between the package material and the external air.

Description

Acoustic coupler

The present invention relates to a coupler, in particular to an acoustic coupler for sound wave transmission.

Generally, for signal transmission between different components with large power supply voltage differences, a coupler or isolator is required to maintain electrical isolation and serve as a signal transmission medium. Common couplers currently include optocouplers or digital couplers. Optocouplers use LEDs as light sources and use corresponding photosensitive elements to achieve electrical-optical-electrical signal conversion and transmission. However, LEDs have a certain service life. When the service life is exceeded, LEDs are prone to aging and other problems, which in turn affects their light-emitting efficiency. In addition, the switching frequency of optocouplers is relatively low, and additional circuits need to be added to barely increase the switching frequency to 10MBd (Mega-Baudrate), which has many limitations in use.

Electromagnetic couplers use different adjacent electromagnetic induction elements to achieve signal conversion and transmission from electric to electromagnetic waves to electric. The switching frequency of optocouplers can be applied to more than 25MBd, with lower power consumption and no aging problems similar to the aforementioned LEDs. However, electromagnetic couplers are prone to electromagnetic interference or interference from external electromagnetic signals due to the use of electromagnetic waves, which can cause trouble in use.

Therefore, how to design a new acoustic coupler to improve the aging or electromagnetic interference problems that are prone to occur in conventional couplers is indeed a topic worth studying.

The purpose of the present invention is to provide an acoustic coupler for transmitting signals using sound waves.

To achieve the above-mentioned purpose, the acoustic coupler of the present invention includes a signal modulation unit, an acoustic wave transmitting unit, an acoustic wave receiving unit, a signal demodulation unit and a packaging structure. A signal modulation unit, used for modulating an input signal into a driving signal; a sound wave transmitting unit, electrically connected to the signal modulation unit, the sound wave transmitting unit transmits a sound wave according to the driving signal; a sound wave receiving unit, used for receiving the sound wave to generate a sensing signal; a signal demodulation unit, electrically connected to the sound wave receiving unit, the signal demodulation unit demodulates the sensing signal into an output signal, and the output signal has a waveform with the same phase as the input signal; and a packaging structure, at least covering the sound wave receiving unit and the sound wave transmitting unit, so that the sound wave receiving unit and the sound wave transmitting unit are electrically isolated from each other at least by the packaging structure. The sound wave emitted from the sound wave receiving unit is transmitted obliquely in the packaging structure, and is reflected by the packaging structure and a top interface before being transmitted obliquely to the sound wave receiving unit.

In one embodiment of the present invention, the sound wave transmitting unit and the sound wave receiving unit are arranged on the same horizontal plane.

In one embodiment of the present invention, the horizontal plane is substantially parallel to the top interface.

In one embodiment of the present invention, the packaging structure is composed of a polymer compound material that can provide acoustic wave transmission properties.

In one embodiment of the present invention, the acoustic coupler further includes a control component electrically connected to the signal demodulation unit, and the control component performs a control operation based on the output signal.

In one embodiment of the present invention, the control component is a driver component or a BJT element including NMOS and PMOS.

In one embodiment of the present invention, the acoustic coupler further includes a chip substrate, the chip substrate includes a groove, wherein the sound wave receiving unit and the sound wave emitting unit are arranged on the chip substrate, and the groove is located between the sound wave receiving unit and the sound wave emitting unit.

In one embodiment of the present invention, the width of the trench is between 10 microns and 100 microns.

In one embodiment of the present invention, the acoustic coupler further includes a plurality of chip substrates, and the acoustic wave receiving unit and the acoustic wave transmitting unit are respectively disposed on two adjacent chip substrates of the plurality of chip substrates.

In one embodiment of the present invention, the distance between two adjacent chip substrates is between 100 microns and 500 microns.

In one embodiment of the present invention, the shortest distance from the interface to the sound wave emitting unit or the sound wave receiving unit is less than 1 mm.

In one embodiment of the present invention, the sound wave transmitting unit includes at least one CMUT transmitting element, the sound wave receiving unit includes at least one CMUT receiving element, and the number of the at least one CMUT transmitting element corresponds to the number of the at least one CMUT receiving element.

In one embodiment of the present invention, when the at least one CMUT transmitting element is plural, the CMUT transmitting elements form a CMUT transmitting element array; when the at least one CMUT receiving element is plural, the CMUT receiving elements form a CMUT receiving element array.

Accordingly, the acoustic coupler of the present invention can effectively transmit signals through the reflection of oblique sound waves, and maintain electrical isolation between the transmitting unit and the receiving unit, without involving the use of optical components and/or electromagnetic induction components, thus avoiding problems such as aging of optical components or electromagnetic interference. In addition, the acoustic coupler of the present invention can be integrated on the same chip to reduce the chip area, simplify the process and reduce costs, and can increase the signal switching frequency.

1, 1a, 1b, 1c, 1d, 1e, 1f: Acoustic coupler

10:Signal modulation unit

20: Sound wave transmitting unit

30: Sound wave receiving unit

40:Signal demodulation unit

41: Transimpedance amplifier

42: Peak detection circuit

50:Packaging structure

51: Top interface

60, 60a, 60b: Control components

70, 701, 702, 703, 704: chip substrate

80: Isolation layer

200: CMUT transmitting/receiving element

210: Dielectric layer

220: Bottom electrode

230: Top electrode

240: Air gap

IN: signal input pin

OUT: signal output pin

GND: ground pin

V _ps : External power supply pin

V _in : input signal

V _out : output signal

Figure 1A is a circuit block diagram of the acoustic coupler of the present invention.

Figure 1B is a schematic diagram of the acoustic coupler of the present invention.

FIG2A is a schematic diagram of the first embodiment of the acoustic coupler of the present invention.

FIG2B is a schematic diagram of the signal transmitted by the first embodiment of the acoustic coupler of the present invention.

Figure 3 is a schematic diagram of the second embodiment of the acoustic coupler of the present invention.

Figure 4 is a schematic diagram of the third embodiment of the acoustic coupler of the present invention.

Figure 5 is a schematic diagram of the fourth embodiment of the acoustic coupler of the present invention.

FIG6 is a schematic diagram of the fifth embodiment of the acoustic coupler of the present invention.

FIG7 is a schematic diagram of the sixth embodiment of the acoustic coupler of the present invention.

FIG8 is a schematic diagram of the seventh embodiment of the acoustic coupler of the present invention.

FIG9A is a schematic diagram of a single CMUT transmitting/receiving element used in the acoustic coupler of the present invention.

FIG9B is a schematic diagram of the multiple CMUT transmitting/receiving elements used in the acoustic coupler of the present invention.

Since the various aspects and embodiments are only illustrative and non-restrictive, after reading this specification, a person with ordinary knowledge may also have other aspects and embodiments without departing from the scope of the invention. The features and advantages of these embodiments will be more prominent according to the following detailed description and patent application scope.

In this document, "a" or "an" is used to describe the elements and components described herein. This is only for the convenience of explanation and to provide a general meaning to the scope of the present invention. Therefore, unless it is obvious that it is otherwise intended, such description should be understood to include one or at least one, and the singular also includes the plural.

In this article, the terms "first" or "second" and similar ordinal numbers are mainly used to distinguish or refer to the same or similar elements or structures, and do not necessarily imply the spatial or temporal order of these elements or structures. It should be understood that in certain situations or configurations, ordinal numbers can be used interchangeably without affecting the implementation of this creation.

As used herein, the terms "include", "have" or any other similar terms are intended to cover a non-exclusive inclusion. For example, an element or structure containing multiple elements is not limited to those elements listed herein, but may include other elements that are not expressly listed but are generally inherent to the element or structure.

Please refer to FIG. 1A and FIG. 1B , wherein FIG. 1A is a circuit block diagram of the acoustic coupler of the present invention, and FIG. 1B is a schematic diagram of the acoustic coupler of the present invention. As shown in FIG. 1A and FIG. 1B , the acoustic coupler 1 of the present invention mainly includes a signal modulation unit 10, an acoustic wave transmitting unit 20, an acoustic wave receiving unit 30, a signal demodulation unit 40 and a packaging structure 50. The signal modulation unit 10 is composed of an amplitude modulation circuit (Amplitude Modulation Circuit), and the signal modulation unit 10 can be provided with a signal input contact IN, a ground contact GND and an external power supply contact V _ps . The signal modulation unit 10 is used to receive an input signal _Vin and modulate the input signal _Vin into a driving signal.

The sound wave transmitting unit 20 is electrically connected to the signal modulation unit 10. The sound wave transmitting unit 20 is used to receive the driving signal from the signal modulation unit 10 and transmit sound waves according to the driving signal. In the present invention, the sound wave transmitting unit 20 includes at least one CMUT (capacitive micromachined ultrasonic transducer, CMUT for short) transmitting element, and the number of at least one CMUT transmitting element is changed according to different design requirements.

The sound wave receiving unit 30 is used to receive the sound wave emitted by the sound wave transmitting unit 20 and generate a sensing signal according to the sound wave. The sound wave receiving unit 30 includes at least one CMUT receiving element, and the number of the at least one CMUT transmitting element corresponds to the number of the at least one CMUT receiving element. In terms of design, the sound wave receiving unit 30 and the sound wave transmitting unit 20 need to be electrically isolated (such as the area separated by the dotted line in Figure 1A, which can achieve electrical isolation by structural design and/or materials); in addition, the sound wave transmitting unit 20 and the sound wave receiving unit 30 are arranged on the same horizontal plane, and both are arranged along the horizontal plane, but the present invention is not limited to this. For example, the sound wave transmitting unit 20 and the sound wave receiving unit 30 can each be arranged along the horizontal plane, but there can be a height difference between the sound wave transmitting unit 20 and the sound wave receiving unit 30.

The signal demodulation unit 40 is electrically connected to the sound wave receiving unit 30. The signal demodulation unit 40 is composed of a signal demodulation circuit, and the signal demodulation unit 40 can be provided with a signal output contact OUT, a ground contact GND and an external power supply contact _Vps . The signal demodulation unit 40 is used to receive the sensing signal from the sound wave receiving unit 30, and demodulate the sensing signal into an output signal _Vout .

The packaging structure 50 at least covers the sound wave receiving unit 30 and the sound wave emitting unit 20, so that the sound wave receiving unit 30 and the sound wave emitting unit 20 are at least electrically isolated by the packaging structure 50, and the sound wave can be transmitted through the packaging structure 50. Of course, in different embodiments, after the packaging process, the packaging structure 50 can also cover other electrical components or structures of the acoustic coupler 1, so that the acoustic coupler 1 of the present invention can be combined with the aforementioned units and other electrical components or structures through the packaging structure 50 to form an integrated structure, and achieve the overall packaging effect of the acoustic coupler 1 of the present invention. In addition, the packaging structure 50 is composed of a polymer compound material that can provide sound wave transmission characteristics, such as epoxy resin (Expoy), but the packaging structure 50 can also be replaced by other polymer compound materials.

After the packaging structure 50 is formed, the packaging structure 50 will form a plurality of interfaces, which include at least a top interface 51, for providing a sound wave reflection effect. In one embodiment of the present invention, the top interface 51 of the packaging structure 50 is substantially parallel to the aforementioned horizontal plane for setting the sound wave transmitting unit 20 and the sound wave receiving unit 30, so as to facilitate the reflection of the sound wave. Accordingly, after the acoustic coupler 1 of the present invention completes the packaging process, the packaging structure 50 can be applied to provide component packaging and sound wave transmission effects at the same time, reducing the process steps and reducing the manufacturing cost. In addition, in one embodiment of the present invention, the shortest distance (i.e., vertical distance) from the aforementioned top interface 51 to the sound wave transmitting unit 20 or the sound wave receiving unit 30 is less than 1 mm, but the present invention is not limited thereto.

The following will further explain the actual application examples and operation methods of the acoustic coupler of the present invention. Please refer to Figures 2A and 2B, wherein Figure 2A is a schematic diagram of the first embodiment of the acoustic coupler of the present invention, and Figure 2B is a schematic diagram of the signal transmitted by the first embodiment of the acoustic coupler of the present invention. As shown in Figures 2A and 2B, in this embodiment, the acoustic coupler 1 of the present invention receives an input signal _Vin and an oscillator signal _Vosc through a signal modulation unit 10, wherein the input signal _Vin is a square wave signal with a frequency spectrum from DC to 20MHz, and the oscillator signal _Vosc has a frequency from 10MHz to 50MHz. The signal modulation unit 10 modulates the input signal _Vin and the oscillator signal _Vosc into a driving signal _Vac , and transmits the driving signal _Vac to the sound wave transmitting unit 20. After receiving the driving signal _Vac , the sound wave transmitting unit 20 can transmit the corresponding sound wave according to the driving signal _Vac . A part of the sound wave is obliquely transmitted from the sound wave transmitting unit 20 through the packaging structure 50, contacts the packaging structure 50 and the top interface 51, and then is obliquely transmitted to the sound wave receiving unit 30 after being reflected.

After receiving the sound wave, the sound wave receiving unit 30 can generate a sensing signal I _s according to the sound wave, wherein the sensing signal I _s is a current signal from 50nA to 1000nA, and the sensing signal I _s has an additional signal transmission time difference Δt relative to the driving signal V _ac . The signal demodulation unit 40 may include a transimpedance amplifier (TIA, transimpedance amplifier) 41 and a peak detection (PD, peak detection) circuit 42. The sensing signal I _s is first transmitted to the transimpedance amplifier 41 to be converted into a receiving signal V _rx , wherein the transimpedance amplifier 41 may have a resistance of 1k~1M Ohm according to design; then the converted receiving signal V _rx is transmitted to the peak detection circuit 42 , and the peak detection circuit 42 performs signal restoration according to the waveform envelope of the receiving signal V _rx to generate an output signal V _out .

It can be seen that the acoustic coupler 1 of the present invention can convert the received input signal _Vin into the output signal _Vout , and the input signal _Vin and the output signal _Vout have waveforms with the same phase. In the present invention, the input signal _Vin can be a voltage signal obtained from a high voltage region, and the output signal _Vout can be a voltage signal supplied to a low voltage region, but the present invention is not limited thereto. For example, _Vin can be a voltage signal obtained from a low voltage region, and _Vout can be a voltage signal obtained from a high voltage region. Therefore, the acoustic coupler 1 of the present invention can effectively achieve the signal transmission effect between the high voltage region and the low voltage region by transmitting sound waves.

Please refer to FIG3 for a schematic diagram of the second embodiment of the acoustic coupler of the present invention. This embodiment is an application variation of the aforementioned first embodiment. As shown in FIG3 , in this embodiment, the acoustic coupler 1a of the present invention further includes a control component 60a. The control component 60a is electrically connected to the signal demodulation unit 40, so that the output signal V _out from the signal demodulation unit 40 can generate a corresponding current to the control component 60a through the resistor R, and the control component 60a can perform corresponding control operations according to the current. In this embodiment, the control component 60a is a BJT (i.e., bipolar junction transistor, Bipolar Junction Transistor, referred to as BJT) element. The BJT element can be connected to an external load and act as a switch (power switch) of the external load. Accordingly, the generation or non-generation of the output signal V _out will cause the control component 60 a to correspondingly execute a circuit conduction or disconnection operation, so that the required switch function can be achieved through the control component 60 a.

Please refer to FIG4 for a schematic diagram of the third embodiment of the acoustic coupler of the present invention. This embodiment is an application variation of the aforementioned first embodiment. As shown in FIG4 , in this embodiment, the control component 60b of the acoustic coupler 1b of the present invention is a driver component including NMOS (i.e., N-type metal oxide semiconductor, N-Metal-Oxide-Semiconductor, referred to as NMOS) and PMOS (i.e., P-Metal-Oxide-Semiconductor, referred to as NMOS). The aforementioned driver component can be connected to an external device and serve as a gate driver of the external device. Accordingly, whether the output signal V _out is generated or not will cause the control component 60b to perform a corresponding circuit switching operation, so as to achieve the required gate drive function through the control component 60b.

The detailed structure and circuit configuration of the acoustic coupler of the present invention will be further described below. Please refer to FIG5 which is a schematic diagram of the fourth embodiment of the acoustic coupler of the present invention. As shown in FIG5, in this embodiment, the acoustic coupler 1c of the present invention further includes a single chip substrate 70. The chip substrate 70 is mainly used as a base element for setting other circuit elements and/or material layers. The chip substrate 70 mainly adopts a non-doped or low-doped silicon substrate. The signal modulation unit 10 and the signal demodulation unit 40 can be set in the chip substrate 70, and the signal modulation unit 10 and the signal demodulation unit 40 can each be matched with a corresponding PMIC (i.e., power management integrated circuit, Power Management Integrated Circuit, referred to as PMIC) to provide the voltage required by the aforementioned units (e.g., V _dc ) through the PMIC. The chip substrate 70 may include a trench 71. The arrangement of the trench 71 is combined with the non-doped or low-doped material properties of the chip substrate 70 itself, so that the two parts of the chip substrate 70 separated by the trench 71 are electrically isolated as much as possible. In this embodiment, the width of the trench 71 is between 10 microns and 100 microns, but the present invention is not limited thereto.

The isolation layer 80 is formed on the chip substrate 70, and the isolation layer 80 uniformly covers the surface of one side of the entire chip substrate 70 to provide an electrical isolation effect between the chip substrate 70 itself and other components disposed on the chip substrate _70. In the present embodiment, the isolation layer 80 can be composed of _SiO2 or _Si3N4 , but the present invention is not limited thereto. The aforementioned chip substrate 70 and the isolation layer 80 can be formed into the required circuit elements and/or structures by an integrated circuit process. In addition, during the process, the aforementioned contacts of the signal modulation unit 10, the signal demodulation unit 40 and the PMIC disposed in the chip substrate 70 can be exposed to the isolation layer 80 to facilitate the electrical connection of these contacts with the corresponding components or power sources.

In this embodiment, the sound wave receiving unit 30 and the sound wave emitting unit 20 are substantially horizontally arranged on the same chip substrate 70, and the sound wave receiving unit 30 and the sound wave emitting unit 20 are arranged on the same horizontal plane. The sound wave receiving unit 30 and the sound wave emitting unit 20 are electrically isolated from the chip substrate 70 by the isolation layer 80, and the groove 71 is located between the sound wave receiving unit 30 and the sound wave emitting unit 20. Since the sound wave receiving unit 30 and the sound wave emitting unit 20 are both composed of corresponding CMUT elements, the sound wave receiving unit 30 and the sound wave emitting unit 20 can form the required circuit or/and structure through the CMUT process, but the present invention is not limited to this.

In this embodiment, the packaging material can cover the entire chip substrate 70 and the sound wave receiving unit 30 and the sound wave transmitting unit 20 disposed thereon through the packaging process, and fill the groove 71 of the chip substrate 70 to form an overall packaging structure 50. Therefore, the sound wave receiving unit 30 and the sound wave transmitting unit 20 can be electrically isolated by the packaging structure 50 and the chip substrate 70, and the sound waves can be transmitted through the packaging structure 50. Accordingly, the various components of the acoustic coupler 1c of the present invention can be integrated on a single chip substrate 70 to form a single chip structure, simplifying the complexity of the process.

The following will illustrate other embodiments of the acoustic coupler of the present invention by using a plurality of chip substrates, and the number of the plurality of chip substrates depends on the chip size requirements. Please refer to FIG6 for a schematic diagram of the fifth embodiment of the acoustic coupler of the present invention. This embodiment is a structural variation of the aforementioned fourth embodiment. As shown in FIG6 , in this embodiment, the acoustic coupler 1d of the present invention includes two chip substrates 701, 702, and the two chip substrates 701, 702 are disposed adjacent to each other and spaced apart. In one embodiment of the present invention, the distance between the two adjacent chip substrates 701, 701 is between 100 microns and 500 microns, but the present invention is not limited thereto. The materials and structural designs used in the chip substrates 701 and 702 are similar to those in the fourth embodiment, except that the chip substrate 701 is mainly provided with the sound wave transmitting unit 20, the signal modulation unit 10 and its corresponding PMIC to form an independent chip structure, while the other chip substrate 702 is mainly provided with the sound wave receiving unit 30, the signal demodulation unit 40 and its corresponding PMIC to form another independent chip structure. After the packaging structure 50 is formed by the packaging process, the sound wave receiving unit 30 and the sound wave transmitting unit 20 can be completely electrically isolated by the packaging structure 50, and the sound waves can be transmitted by the packaging structure 50. Accordingly, the acoustic coupler 1d of the present invention can effectively isolate the sound wave transmitting function from the sound wave receiving function, and can also reduce the adverse effects of signal transmission caused by the poor electrical isolation effect of the substrate material.

Please refer to FIG. 7 for a schematic diagram of the sixth embodiment of the acoustic coupler of the present invention. This embodiment is a structural variation of the aforementioned fourth embodiment. As shown in FIG. 7 , in this embodiment, the acoustic coupler 1e of the present invention includes three chip substrates 701, 702, and 703, and the three chip substrates 701, 702, and 703 are arranged adjacent to each other and spaced apart. The materials and structural designs used in the chip substrates 701, 702, and 703 are similar to those of the aforementioned fourth embodiment, except that the chip substrate 701 is mainly provided with a signal modulation unit 10 and its corresponding PMIC to form an independent modulation chip structure, the chip substrate 702 is mainly provided with an acoustic wave transmitting unit 20 and an acoustic wave receiving unit 30 to form an independent acoustic coupling chip structure, and the chip substrate 703 is mainly provided with a signal demodulation unit 40 and its corresponding PMIC to form another independent demodulation chip structure. The chip substrate 702 is separated into two parts by the groove 71 for setting the sound wave transmitting unit 20 and the sound wave receiving unit 30 respectively, and maintaining electrical isolation. The aforementioned independent modulation chip structure can be manufactured by any CMOS integrated circuit process, the aforementioned independent acoustic coupling chip structure can be manufactured by any silicon sensor chip process, and the aforementioned independent demodulation chip structure can be manufactured by any CMOS process or BCD integrated circuit process. Accordingly, the acoustic coupler 1e of the present invention can be manufactured using the most suitable process technology for different chips to reduce the difficulty of chip process integration and improve the electrical isolation effect of two adjacent units.

Please refer to Fig. 8 for a schematic diagram of the seventh embodiment of the acoustic coupler of the present invention. This embodiment is a structural variation example combining the fifth embodiment and the sixth embodiment. As shown in Fig. 8, in this embodiment, the acoustic coupler 1f of the present invention includes four chip substrates 701, 702, 703, and 704, and the four chip substrates 701, 702, 703, and 704 are arranged adjacent to each other and spaced apart. The materials and structural designs used in the chip substrates 701, 702, 703, and 704 are similar to those of the aforementioned fourth embodiment, with the difference that the chip substrate 701 is mainly provided with a signal modulation unit 10 and its corresponding PMIC to form an independent modulation chip structure, the chip substrate 702 is mainly provided with an acoustic wave transmitting unit 20 to form an independent acoustic wave transmitting chip structure, the chip substrate 703 is mainly provided with an acoustic wave receiving unit 30 to form an independent acoustic wave receiving chip structure, and the chip substrate 704 is mainly provided with a signal demodulation unit 40 and its corresponding PMIC to form another independent demodulation chip structure. The aforementioned independent modulation chip structure can be manufactured by any CMOS integrated circuit process, the aforementioned independent sound wave transmitting chip structure and the independent modulation chip structure can be manufactured by any silicon sensor chip process, and the aforementioned independent demodulation chip structure can be manufactured by any CMOS integrated circuit process or BCD process. Accordingly, the acoustic coupler 1f of the present invention can manufacture units with different functions as independent chips respectively, and manufacture them with the most suitable process technology, so that the best electrical isolation effect can be achieved between each chip.

The structural design of the aforementioned CMUT transmitting/receiving element used in the present invention will be further described below. It should be noted that since the CMUT transmitting element used in the acoustic wave transmitting unit and the CMUT receiving element used in the acoustic wave receiving unit have similar structures, the structural features common to both are used for description. Please refer to Figures 9A and 9B together, wherein Figure 9A is a schematic diagram of a single CMUT transmitting/receiving element used in the acoustic coupler of the present invention, and Figure 9B is a schematic diagram of a plurality of CMUT transmitting/receiving elements used in the acoustic coupler of the present invention. As shown in Figure 9A, the single CMUT transmitting/receiving element 200 used in the acoustic coupler of the present invention includes at least a dielectric layer 210, a bottom electrode 220, and a top electrode 230. The bottom electrode 220 is disposed on the aforementioned isolation layer 80 so as to be electrically isolated from the chip substrate, and the bottom electrode 220 is electrically connected to the signal modulation unit or the signal demodulation unit. The dielectric layer 210 is disposed on the isolation layer 80 and covers the bottom electrode 220, and an air gap 240 is formed between the dielectric layer 210 and the bottom electrode 220 through a process. The top electrode 230 is disposed on the dielectric layer 210, and the top electrode 230 is electrically connected to the corresponding PMIC to obtain a power supply voltage. The dielectric layer 210 can be composed of _{SiO2 , Si3N4} or _AlxOy , but _the present invention is not limited thereto.

As shown in FIG. 9B , in one embodiment of the present invention, when the acoustic coupler of the present invention uses a plurality of CMUT transmitting/receiving elements 200, the CMUT transmitting/receiving elements 200 can form a CMUT transmitting/receiving element array. The CMUT transmitting/receiving element array is composed of N x N CMUT transmitting/receiving elements 200, wherein the bottom electrodes 220 of all CMUT transmitting/receiving elements 200 are electrically connected to each other, and the top electrodes 230 of all CMUT transmitting/receiving elements 200 are electrically connected to each other. Under the condition of the same setting area, the CMUT transmitting/receiving element array composed of a plurality of CMUT transmitting/receiving elements 200 with a smaller volume can improve the stability or yield of the process compared to the use of a single CMUT transmitting/receiving element 200 with a larger volume.

The above embodiments are essentially only for auxiliary explanation and are not intended to limit the embodiments of the subject matter of the application or the application or use of such embodiments. In addition, although at least one exemplary embodiment has been proposed in the above embodiments, it should be understood that there are still a large number of variations of the present invention. It should also be understood that the embodiments described herein are not intended to limit the scope, use or configuration of the claimed subject matter in any way. On the contrary, the above embodiments will provide a simple guide for those with ordinary knowledge in the field to implement one or more of the embodiments described. Furthermore, various changes can be made to the functions and arrangements of the components without departing from the scope defined by the scope of the patent application, and the scope of the patent application includes known equivalents and all foreseeable equivalents at the time of filing this patent application.

1: Acoustic coupler

10:Signal modulation unit

20: Sound wave transmitting unit

30: Sound wave receiving unit

40:Signal demodulation unit

50:Packaging structure

51: Top interface

Claims (13)

An acoustic coupler includes: a signal modulation unit for modulating an input signal into a driving signal; a sound wave transmitting unit electrically connected to the signal modulation unit, the sound wave transmitting unit transmitting a sound wave according to the driving signal; a sound wave receiving unit for receiving the sound wave and generating a sensing signal according to the sound wave; a signal demodulation unit electrically connected to the sound wave receiving unit, the signal demodulation unit demodulating the sensing signal into an output signal , and the output signal and the input signal have the same phase waveform; and a packaging structure, at least covering the sound wave receiving unit and the sound wave emitting unit, so that the sound wave receiving unit and the sound wave emitting unit are at least electrically isolated by the packaging structure; wherein the sound wave emitted from the sound wave emitting unit is transmitted obliquely in the packaging structure, and is reflected by the packaging structure and a top interface before being transmitted obliquely to the sound wave receiving unit. The acoustic coupler as described in claim 1, wherein the acoustic wave transmitting unit and the acoustic wave receiving unit are arranged on the same horizontal plane. An acoustic coupler as described in claim 2, wherein the horizontal plane is substantially parallel to the top interface. An acoustic coupler as described in claim 1, wherein the packaging structure is made of a polymer compound material that can provide acoustic wave transmission properties. The acoustic coupler as described in claim 1 further includes a control component electrically connected to the signal demodulation unit, and the control component performs a control operation based on the output signal. An acoustic coupler as described in claim 5, wherein the control component is a driver component or a BJT element including NMOS and PMOS. The acoustic coupler as described in claim 1 further includes a chip substrate, the chip substrate includes a groove, wherein the sound wave receiving unit and the sound wave emitting unit are arranged on the chip substrate, and the groove is located between the sound wave receiving unit and the sound wave emitting unit. An acoustic coupler as described in claim 7, wherein the width of the groove is between 10 microns and 100 microns. The acoustic coupler as described in claim 1 further includes a plurality of chip substrates, and the acoustic wave receiving unit and the acoustic wave transmitting unit are respectively disposed on two adjacent chip substrates of the plurality of chip substrates. An acoustic coupler as described in claim 9, wherein the distance between the two adjacent chip substrates is between 100 microns and 500 microns. The acoustic coupler as described in claim 1, wherein the shortest distance from the top interface to the acoustic wave emitting unit or the acoustic wave receiving unit is less than 1 mm. The acoustic coupler as described in claim 1, wherein the acoustic wave transmitting unit includes at least one CMUT transmitting element, the acoustic wave receiving unit includes at least one CMUT receiving element, and the number of the at least one CMUT transmitting element corresponds to the number of the at least one CMUT receiving element. An acoustic coupler as described in claim 12, wherein when the at least one CMUT transmitting element is plural, the CMUT transmitting elements form a CMUT transmitting element array; when the at least one CMUT receiving element is plural, the CMUT receiving elements form a CMUT receiving element array.

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