TW201825927A - Ultrasonic wave sensor and electronic device using same - Google Patents

Abstract

The present invention relates to a ultrasonic wave sensor. The ultrasonic wave sensor includes a ultrasonic wave transceiver, a flexible printed circuit and a cover glass. The ultrasonic wave transceiver and the flexible printed circuit are disposed on the same side of the cover glass. The ultrasonic wave transceiver includes a stack-up of a ultrasonic wave transmitting unit and a ultrasonic wave receiving unit. The flexible printed circuit is electrically connected to the ultrasonic wave transmitting unit and the ultrasonic wave receiving unit simultaneously. The present invention also relates to an electrical device using same.

Description

Ultrasonic sensor and electronic device using the same

The invention relates to an ultrasonic sensor, in particular to an ultrasonic sensor using flexible circuit board input and output signals, and an electronic device using the ultrasonic sensor.

Ultrasonic sensing technology is increasingly used in modern life due to its high sensing accuracy and sensitive response. For example, fingerprint sensors used in mobile terminals such as mobile phones and computers, and biomedical detection devices used to detect vital signs such as heart rate, pulse, and blood flow, and also used as portable electronic devices such as mobile phones, PDAs, and tablet computers The key switch is used to detect a finger touch to wake up the portable electronic device. An ultrasonic sensor in the conventional technology mainly includes an ultrasonic transmitting unit for transmitting ultrasonic waves and an ultrasonic receiving unit for receiving ultrasonic waves. The ultrasonic transmitting unit and the ultrasonic receiving unit are The bonding wires are electrically connected to the driving IC to receive signals and transmit signals. In this ultrasonic sensor, the welding process is wasted due to the use of welding wires for electrical connection, and the welding wire may be damaged or broken during long-term use, which easily leads to the failure of the ultrasonic sensor and shortens the use. life.

In view of this, it is necessary to provide an ultrasonic sensor which can save manufacturing manpower, reduce the failure rate, and has a long life.

In addition, it is necessary to provide an electronic device using the ultrasonic sensor.

The invention provides an ultrasonic sensor, which includes an ultrasonic transceiver, a flexible circuit board and a pressure plate. The ultrasonic transceiver and the flexible circuit board are arranged on the same side of the pressure plate. The ultrasonic transceiver includes an upper layer and a lower layer. The ultrasonic transmitting unit and an ultrasonic receiving unit, and the flexible circuit board is electrically connected to the ultrasonic transmitting unit and the ultrasonic receiving unit, respectively.

Further, the ultrasonic transmitting unit and the ultrasonic receiving unit are bonded by a first adhesive layer.

Further, the ultrasonic emission unit includes a first emission electrode, a second emission electrode, and a piezoelectric emission layer disposed between the first emission electrode and the second emission electrode, and the second emission electrode is disposed on the piezoelectric emission layer. The side far from the ultrasonic receiving unit is electrically connected to the flexible circuit board. The first transmitting electrode is disposed on the piezoelectric transmitting layer near the ultrasonic receiving unit and is bent onto the surface of the piezoelectric transmitting layer provided with the second transmitting electrode. It is electrically connected to the flexible circuit board.

Further, the ultrasonic emission unit includes a first emission electrode, a second emission electrode, and a piezoelectric emission layer disposed between the first emission electrode and the second emission electrode. The first emission electrode is disposed on the piezoelectric emission layer. The second transmitting electrode is located near the ultrasonic receiving unit, and the second transmitting electrode is disposed on the side of the piezoelectric transmitting layer away from the ultrasonic receiving unit. The second transmitting electrode is electrically connected to the flexible circuit board, and the first transmitting electrode and the second transmitting electrode are respectively disposed at On different surfaces of the piezoelectric emission layer.

Further, the ultrasonic receiving unit includes a first receiving electrode and a second receiving electrode, and a piezoelectric receiving layer disposed between the first receiving electrode and the second receiving electrode; the second receiving electrode is disposed on the piezoelectric receiving layer. The side far from the ultrasonic transmitting unit is electrically connected to the flexible circuit board. The first receiving electrode is disposed on the piezoelectric receiving layer near the ultrasonic transmitting unit and is bent on the surface of the piezoelectric receiving layer provided with the second receiving electrode. It is electrically connected to the flexible circuit board.

Further, the first adhesive layer has conductivity.

Further, the ultrasonic receiving unit includes a first receiving electrode and a second receiving electrode, and a piezoelectric receiving layer disposed between the first receiving electrode and the second receiving electrode. The first receiving electrode is disposed on the piezoelectric receiving layer. The second receiving electrode is located near the ultrasonic transmitting unit, and the second receiving electrode is disposed on the side of the piezoelectric receiving layer away from the ultrasonic transmitting unit. The second receiving electrode is electrically connected to the flexible circuit board, and the first receiving electrode and the second receiving electrode are respectively disposed at On different surfaces of the piezoelectric receiving layer.

Further, the first transmitting electrode and the second transmitting electrode are electrically connected to the flexible circuit board through the second adhesive layer; the first receiving electrode and the second receiving electrode are electrically connected to the flexible circuit board through the second adhesive layer. The second adhesive layer is conductive.

Further, the size of the piezoelectric emitting layer is larger than that of the piezoelectric receiving layer. Further, one end of the flexible circuit board is disposed between the ultrasonic transceiver and the pressure plate, and the other end is wound along the ultrasonic transceiver so that the flexible circuit board surrounds at least three adjacent sides of the ultrasonic transceiver.

The present invention also provides an electronic device. The electronic device includes an ultrasonic sensor. The ultrasonic sensor includes an ultrasonic transceiver, a flexible circuit board, and a pressure plate. The ultrasonic transceiver and the flexible circuit board. It is arranged on the same side of the pressure plate. One end of the flexible circuit board is arranged between the ultrasonic transceiver and the pressure plate, and the other end is wound along the ultrasonic transceiver so that the flexible circuit board surrounds at least three adjacent sides of the ultrasonic transceiver. The ultrasonic transceiver It comprises an ultrasonic transmitting unit and an ultrasonic receiving unit which are arranged one on top of the other, and the flexible circuit board is electrically connected to the ultrasonic transmitting unit and the ultrasonic receiving unit, respectively.

Compared with the conventional technology, the ultrasonic sensor of the present invention uses only the same flexible circuit board to bypass the ultrasonic transmitting unit and the ultrasonic receiving unit connected to the ultrasonic sensor, thereby saving the ultrasonic sensor. Manufacturing manpower is conducive to reducing the failure rate and increasing the service life.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a sectional view of an ultrasonic sensor according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of an ultrasonic sensor according to a second embodiment of the present invention. 3 is a cross-sectional view of an ultrasonic sensor according to a third embodiment of the present invention. 4 is a cross-sectional view of an ultrasonic sensor according to a fourth embodiment of the present invention. FIG. 5 is a schematic diagram of an electronic device to which a sonic touch device of the present invention is applied.

The ultrasonic sensor of the present invention can be used alone as a sensor, or can be integrated into or used in association with various electronic devices, such as (but not limited to): mobile phones, equipped with multimedia Internet-enabled cellular phone, mobile TV receiver, wireless device, smart phone, Bluetooth device, personal data assistant (PDA), wireless email receiver, handheld or portable computer, mini-notebook computer, note-taking PC, smartbook, tablet, printer, photocopier, scanner, fax machine, Global Positioning System (GPS) receiver / navigator, video camera, digital media player (e.g. MP3 player), video recording Movie cameras, game consoles, watches, clocks, calculators, TV monitors, flat panel displays, e-reading devices (e.g. e-readers), mobile health devices, computer monitors, car displays (including odometer displays and speed Monitors, etc.), cockpit controls and / or displays, camera landscape displays (e.g., rear view camera displays in vehicles), Electronic photos, electronic signage or logos, projectors, building structures, microwave installations, refrigerators, stereo systems, cassette players or players, DVD players, CD players, VCRs, radios, portable memory chips, Scrubbers, dryers, scrubbers / dryers, parking meters, packaging (e.g., in electromechanical systems (EMS) applications that include micro-electromechanical systems (MEMS) applications, and packaging in non-EMS applications), aesthetic structures (e.g., Image display of a piece of jewelry or clothing) and various EMS devices. The teachings herein can also be used in applications such as (but not limited to): electronic switching devices, RF filters, sensors, accelerometers, gyroscopes, motion sensing devices, magnetometers, for consumer electronics Inertial components of equipment, parts of consumer electronics, variable reactors, liquid crystal devices, electrophoretic devices, driving schemes, manufacturing processes and electronic test equipment.

Referring to FIG. 1, the ultrasonic sensor 100 disclosed in the first embodiment of the present invention includes an ultrasonic transceiver 110, a flexible circuit board 120, and a pressure plate 130. The ultrasonic transceiver 110 and the flexible circuit board 120 are disposed on the same side of the platen 130. One end of the flexible circuit board 120 is disposed between the ultrasonic transceiver 110 and the platen 130, and the other end is bent to surround at least three of the ultrasonic transceiver 110. side.

The ultrasonic transceiver 110 includes an ultrasonic transmitting unit 112 and an ultrasonic receiving unit 114 which are stacked on top of each other. The ultrasonic transmitting unit 112 and the ultrasonic receiving unit 114 are bonded by a first adhesive layer 116. The ultrasonic receiving unit 114 is located on a side of the ultrasonic transmitting unit 112 away from the pressure plate 130. The flexible circuit board 120 bent and surrounding the ultrasonic transceiver 110 is electrically connected to the ultrasonic transmitting unit 112 and the ultrasonic receiving unit 114, respectively.

The ultrasonic emission unit 112 includes a first emission electrode 1122, a second emission electrode 1124, and a piezoelectric emission layer 1126 disposed between the first emission electrode 1122 and the second emission electrode 1124. The second transmitting electrode 1124 is disposed on the piezoelectric transmitting layer 1126 away from the ultrasonic receiving unit 114. The second transmitting electrode 1124 and the flexible circuit board 120 are electrically connected to a part of the ultrasonic transceiver 110 and the pressing plate 130. The first transmitting electrode 1122 is disposed on the side of the piezoelectric emitting layer 1126 near the ultrasonic receiving unit 114, and is bent and extended to the piezoelectric emitting layer 1126. The surface on which the second emitting electrode 1124 is formed is electrically connected to the flexible circuit board 120. . This structure of the first emitting electrode 1122 is also often referred to as a "reverse electrode". By being electrically connected to the flexible circuit board 120 respectively, the first transmitting electrode 1122 and the second transmitting electrode 1124 respectively apply a voltage to the piezoelectric transmitting layer 1126, and the voltage difference between the first transmitting electrode 1122 and the second transmitting electrode 1124 makes the voltage The electric emission layer 1126 vibrates and emits an ultrasonic wave. In order to control the voltage difference between the first transmitting electrode 1122 and the second transmitting electrode 1124, one of the voltages of the first transmitting electrode 1122 and the second transmitting electrode 1124 may be controlled to be a constant voltage, which may be 0, that is, the first One of the transmitting electrode 1122 and the second transmitting electrode 1124 is grounded through the flexible circuit board 120. By changing the other voltage, the voltage difference between the first transmitting electrode 1122 and the second transmitting electrode 1124 can be adjusted to control the emitted ultrasonic waves. In this embodiment, the first transmitting electrode 1122 is grounded. In other embodiments of the present invention, the second transmitting electrode 1124 may be grounded.

The ultrasound receiving unit 114 includes a first receiving electrode 1142 and a second receiving electrode 1144, and a piezoelectric receiving layer 1146 disposed between the first receiving electrode 1142 and the second receiving electrode 1144. The second receiving electrode 1144 is disposed on a side of the piezoelectric receiving layer 1146 away from the ultrasonic transmitting unit 112. The second receiving electrode 1144 is electrically connected to the flexible circuit board 120. The first receiving electrode 1142 is disposed on the piezoelectric receiving layer 1146 near the ultrasonic transmitting unit 112, and is bent to extend to the piezoelectric receiving layer 1146. The surface on which the second receiving electrode 1144 is formed is electrically connected to the flexible circuit board 120. . The piezoelectric receiving layer 1146 receives ultrasonic waves emitted from the piezoelectric transmitting layer 1126 and is reflected by a finger to generate vibration. The vibration of the piezoelectric receiving layer 1146 generates electrical signals, and is electrically connected to the first receiving electrode 1142 and the second receiving electrode 1144. The flexible circuit board 120 outputs the electrical signal to a processor (not shown). In order to read and record the electrical signal between the first receiving electrode 1142 and the second receiving electrode 1144, one of the voltages of the first receiving electrode 1142 and the second receiving electrode 1144 may be controlled to be a constant voltage, and the constant voltage may be 0, That is, one of the first receiving electrode 1142 and the second receiving electrode 1144 is grounded through the flexible circuit board 120. In this embodiment, the first receiving electrode 1142 is grounded. In other embodiments of the present invention, the second receiving electrode 1144 may be grounded.

The first emitting electrode 1122, the second emitting electrode 1124, the first emitting electrode 1122, and the second emitting electrode 1124 may be a monolithic conductive structure or a patterned conductive structure. For example, but not limited to, silver, aluminum , Copper, nickel, gold and other high-conductivity materials, can also be made of conductive materials such as transparent conductive materials (such as indium tin oxide, indium zinc oxide), silver, carbon nanotubes or graphene.

In the first embodiment of the present invention, the size of the piezoelectric emitting layer 1126 and the piezoelectric receiving layer 1146 are equal. In other embodiments of the present invention, the sizes of the piezoelectric emitting layer 1126 and the piezoelectric receiving layer 1146 may be different. The piezoelectric emitting layer 1126 and the piezoelectric receiving layer 1146 are made of a piezoelectric material, which includes barium titanate (BaiO3), lead titanate (PbiO3), and lead zirconate titanate (Pb (Zri) O3, PZT), lead tantalate (PST), quartz, (Pb, Sm) iO3, PMN (Pb (MgNb) O3) -PT (PbiO3), polyvinylidene fluoride (PVDF), and polyvinylidene fluoride-three Fluoroethylene (PVDF-TrFE) copolymers, iron fluoride and other PTFE polymers, polydichloroethylene (PVDC) homopolymers and copolymers, polytetrafluoroethylene (PTFE) homopolymers and copolymers, and bromination Diisopropylamine (DIPAB) and so on.

The first adhesive layer 116 may be conductive or non-conductive. When the first adhesive layer 116 is conductive, the first transmitting electrode 1122 and the first receiving electrode 1142 are electrically connected, and the voltages thereof are equal. At this time, the first adhesive layer 116 may be all conductive adhesives. For example, the first adhesive layer 116 may be anisotropic conductive adhesive, or a part thereof may be a conductive adhesive, and the other part may be a non-conductive adhesive. For example, the middle portion of the first adhesive layer 116 is a conductive adhesive, and the outside of the conductive adhesive is a non-conductive adhesive.

When the first adhesive layer 116 is not conductive, the voltages of the first transmitting electrode 1122 and the first receiving electrode 1142 are controlled by the flexible circuit board 120, respectively. At this time, all the first adhesive layers 116 are non-conductive glue. Since the surfaces of the first transmitting electrode 1122 and the first receiving electrode 1142 are both rough surfaces, the first adhesive layer 116 can fill the rough surfaces of the first transmitting electrode 1122 and the first receiving electrode 1142 to reduce the ultrasonic transmission loss. In the first embodiment of the present invention, the first adhesive layer 116 is a non-conductive adhesive.

The flexible circuit board 120 has a first surface 120a, or an inner surface, and a second surface 120b, or an outer surface. The first surface 120 a is a surface electrically connected to the ultrasonic transceiver 110, and the second surface 120 b is a surface opposite to the first surface 22. The flexible circuit board 120 includes at least three parts: a first part 122 electrically connected to the ultrasound transmitting unit 112, a second part 124 electrically connected to the ultrasound receiving unit 114, and a first part 122 connecting the first part 122 and the second part 124. Three parts 126. A plurality of pads 128 are also formed on the first surface 120a of the first portion 122 and the first surface 120a of the second portion 124 of the flexible circuit board 120. The ultrasonic transmitting unit 112 and the ultrasonic receiving unit 114 are respectively bonded by a second adhesive. The bonding layer 140 is adhered to a pad 128. The second adhesive layer 140 is a conductive adhesive. All of the second adhesive layer 140 may be a conductive adhesive, for example, anisotropic conductive adhesive, or a part of the second adhesive layer 140 may be a conductive adhesive and another part may be a non-conductive adhesive. For example, the middle portion of the second adhesive layer 140 is a conductive adhesive, and the outside of the conductive adhesive is a non-conductive adhesive. Since the surfaces of the second transmitting electrode 1124 and the second receiving electrode 1144 are both rough surfaces, the second adhesive layer 140 can fill the rough surfaces of the second transmitting electrode 1124 and the second receiving electrode 1144, thereby reducing ultrasonic transmission loss.

The pad 128 is formed of a conductive material, for example, a metallic material such as solder or copper. In this embodiment, the pad 128 is a copper pad. In addition, in this embodiment, a terminal portion 129 for connecting a driving IC is also formed on the first surface 120 a of the second portion 124 of the flexible circuit board 120. In other embodiments of the present invention, the terminal portion 129 for connecting the driving IC is disposed on the first surface 120 a of the first portion 122 of the flexible circuit board 120. In other embodiments of the present invention, the driving IC may also be directly integrated on the flexible circuit board 120.

Specifically, the second transmitting electrode 1124 of the ultrasonic transmitting unit 112 is connected to a pad 128 through the second adhesive layer 140 and further connected to the flexible circuit board 120. The first emitting electrode 1122 is bent and extended to the piezoelectric emitting layer 1126 and the second emitting electrode 1124 is disposed on a surface thereof connected to another pad 128 and further connected to the flexible circuit board 120. The second receiving electrode 1144 of the ultrasonic receiving unit 114 is connected to a pad 128 through the second adhesive layer 140 and is further connected to the flexible circuit board 120. The first receiving electrode 1142 is bent and extended to the surface of the piezoelectric receiving layer 1146 on which the second receiving electrode 1144 is disposed, and is connected to a pad 128 through the second adhesive layer 140 and then to the flexible circuit board 120.

The pressing plate 130 is disposed on the second surface 120 b of the flexible circuit board 120 corresponding to the position of the ultrasonic transceiver 110. The pressure plate 130 and the flexible circuit board 120 are adhered by a third adhesive layer 150. In this embodiment, the pressing plate 130 is disposed on the second surface 120 b of the first portion 122 of the flexible circuit board 120. In other embodiments of the present invention, the pressing plate 130 may be disposed on the second surface 120 b of the second portion 124 of the flexible circuit board 120.

The pressing plate 130 may be, but is not limited to, plastic, ceramic, sapphire, composite material, metal and metal alloy, metal-filled polymer, polycarbonate, and glass. In some embodiments, the platen 130 may be a platen, such as a protective glass cover or protective lens for a display. In some embodiments, the platen 130 may be a metal or a metal-filled polymer such as aluminum, aluminum alloy, chromium-molybdenum, stainless steel. Inspection and imaging can be performed when needed through, for example, a relatively thick platen of 1 mm or more. In some embodiments, a housing or housing for an electronic device may serve as a pressure plate. In some embodiments, the back, side, or front of the mobile device housing can act as a pressure plate, as the ultrasonic sensors described herein can image fingerprints or collect biometric information directly through the housing wall. In some embodiments, for example, a thin layer of polyurethane, a coating of acrylic, parylene, or a diamond-like coating (DLC) may serve as a pressure plate.

In this embodiment, the third adhesive layer 150 is a non-conductive adhesive. In other embodiments of the present invention, the third adhesive layer 150 may be all conductive adhesive or part of the conductive adhesive. Similarly, the third adhesive layer 150 can fill the unevenness of the surfaces of the flexible circuit board 120 and the pressing plate 130, thereby reducing the ultrasonic transmission loss.

Please refer to FIG. 1 again. The working principle of the ultrasonic sensor 100 of the present invention is as follows: When no finger touches the surface of the pressure plate, according to the input control signal, the flexible circuit board 120 passes the first portion 122 to the first transmitting electrode 1122. The second transmitting electrode 1124 and the second transmitting electrode 1124 respectively transmit electrical signals, so that a voltage difference is formed between the first transmitting electrode 1122 and the second transmitting electrode 1124. The piezoelectric emission layer 1126 vibrates and generates an ultrasonic wave under the action of the voltage difference. The ultrasonic wave travels toward the pressure plate 130. When it encounters the pressure plate 130, a part of the ultrasonic wave penetrates the pressure plate 130 and continues to travel outward, and another part of the ultrasound It is reflected by the pressure plate 130 and is received by the piezoelectric receiving layer 1146 and converted into an electrical signal. The first receiving electrode 1142 and the second receiving electrode 1144 are transmitted to the second portion 124 of the flexible circuit board 120 and output to the controller. The controller processes it as a reference signal. When a finger touches the surface of the pressure plate, according to the input control signal, the flexible circuit board 120 transmits electrical signals to the first transmitting electrode 1122 and the second transmitting electrode 1124 through the first portion 122 so that the first transmitting electrode 1122 and the second transmitting electrode respectively. A voltage difference is formed between the electrodes 1124, and the piezoelectric emission layer 1126 vibrates and generates an ultrasonic wave under the action of the voltage difference. The ultrasonic wave travels in the direction of the pressing plate 130. When it touches a finger on the pressing plate 130, a part of the ultrasonic wave is caught by the finger Absorbed, another part of the ultrasonic wave is reflected back by the pressing plate 130 and is received by the piezoelectric receiving layer 1146 and converted into an electrical signal. The first receiving electrode 1142 and the second receiving electrode 1144 are transmitted to the second portion 124 of the flexible circuit board 120 and output. The signal is given to the controller and processed by the controller as a signal, which is compared with a reference signal to determine whether a touch object touches the ultrasonic sensor 100 and further determines whether to wake up the electronic device.

The ultrasonic sensor 100 in the above-mentioned first embodiment only uses the same flexible circuit board 120 to bypass the ultrasonic transmitting unit 112 and the ultrasonic receiving unit 114 connected to the ultrasonic sensor, thereby saving the manufacturing of the ultrasonic sensor. Manpower is conducive to reducing the failure rate and increasing the service life. In addition, the ultrasonic sensor 100 in the first embodiment uses an adhesive layer to fill the unevenness of the surface of the internal components of the ultrasonic sensor 100 to reduce the ultrasonic transmission loss.

Please refer to FIG. 2 together. FIG. 2 is an ultrasonic sensor 200 in the second embodiment, and its structure is substantially the same as that of the ultrasonic sensor 100 in the first embodiment. To repeat, the difference is that the ultrasonic transmitting unit 212 is located on the side of the ultrasonic receiving unit 214 away from the pressure plate 230, and the pressure plate 230 is disposed on the second surface 220b of the second portion 224 of the flexible circuit board 220 corresponding to the ultrasonic receiving unit 214. Position, and a terminal portion 229 for driving connection is provided on the first surface 220a of the first portion 222 of the flexible circuit board 220. The ultrasonic sensor 200 of the second embodiment of the present invention has the same working principle as the ultrasonic sensor 100 of the first embodiment, and therefore will not be described again.

Please refer to FIG. 3. FIG. 3 is an ultrasonic sensor 300 according to a third embodiment of the present invention. The structure of the ultrasonic sensor 300 is substantially the same as that of the ultrasonic sensor 100 in the first embodiment of the present invention. To repeat, the difference lies in that the size of the piezoelectric emitting layer 3126 and the piezoelectric receiving layer 3146 are different. The size of the piezoelectric emitting layer 3126 is larger than that of the piezoelectric receiving layer 3146. Since the ultrasonic waves emitted by the ultrasonic transmitting unit 312 arrive A part of the back of the pressure plate 330 is absorbed by a finger, and the energy of the ultrasound reflected by the ultrasound receiving unit 314 is small. Therefore, the piezoelectric transmitting layer 3126 of the ultrasonic transmitting unit 312 is larger than the piezoelectric receiving layer 3146 of the ultrasonic receiving unit 314 to provide greater vibration energy, enhance the signal strength received by the ultrasonic receiving unit 314, and improve the ultrasonic Sensitivity of the sensor 300. The ultrasonic sensor 300 of the first embodiment of the present invention has the same working principle as the ultrasonic sensor 100 of the first embodiment, and therefore will not be described again.

Please refer to FIG. 4 together. FIG. 4 is an ultrasonic sensor 400 according to a fourth embodiment of the present invention, and its structure is substantially the same as that of the ultrasonic sensor 400 in the third embodiment of the present invention. The details are not repeated here. The difference is that in the third embodiment of the present invention, the first adhesive layer 416 is conductive, and the first receiving electrode 4142 is electrically connected to the first emitting electrode 4122 through the conductive first adhesive layer 416. Since the first transmitting electrode 4122 is electrically connected to the flexible circuit board 420, the voltage of the first receiving electrode 4142 and the first transmitting electrode 4122 is equal. Therefore, the first receiving electrode 4142 and the second receiving electrode 4144 can be disposed on different surfaces on both sides of the piezoelectric receiving layer 4146 without extending to the same surface as the second receiving electrode 4144. Compared with the first to third embodiments, the first receiving electrode 4142 does not need to be bent to extend to the same surface as the second receiving electrode 4144, and therefore, the polarization cost can be reduced. The ultrasonic sensor 400 of the fourth embodiment of the present invention has the same working principle as the ultrasonic sensor 100 of the first embodiment, and therefore will not be described again. It can be understood that, in other embodiments of the present invention, the first receiving electrode may be electrically connected to the first transmitting electrode through a conductive first adhesive layer, and the first transmitting electrode is electrically connected to the flexible circuit board. Therefore, the first emission electrode and the second emission electrode are disposed on different surfaces on both sides of the piezoelectric emission layer, and the first emission electrode does not need to be bent and extended to the same surface as the second emission electrode. Similarly, polarization costs can also be reduced.

Referring to FIG. 5, the present invention also provides an electronic device 500 using the ultrasonic sensor 100 according to the first embodiment of the present invention. As shown in FIG. 5, only the electronic device 500 is a mobile phone as an example. In other embodiments, the electronic device 10 may also be a personal computer, a smart home appliance, an industrial controller, or the like. When the electronic device 500 is a mobile phone, it includes a display area 510. A surface having a display area 510 is a front surface 500a, and a surface opposite to the front surface 500a is a back surface 500b. The ultrasonic sensor 100 is disposed on the front surface 500a of the electronic device 500 and is located below the display area 510. At this time, the ultrasonic sensing The device 100 can be used as a home button of a mobile phone, that is, a home screen button. In other embodiments of the present invention, the ultrasonic sensor 100 may be further disposed on the back surface 500 b or even the side surface of the electronic device 500. The ultrasonic sensor 100 can be used as a key switch to detect a touch of a touch object such as a finger to determine whether to wake up the key switch to detect a touch of a finger to wake up the portable electronic device. Although, the electronic device 500 of the present embodiment employs the ultrasonic sensor 100 of the first embodiment of the present invention. It can be understood that any one of the first to fourth embodiments of the present invention can be used in the electronic device 500.

100, 200, 300, 400‧‧‧ Ultrasonic sensors

110, 210‧‧‧ Ultrasonic Transceiver

112, 212, 312‧‧‧ Ultrasonic transmitting units

114, 214, 314‧‧‧ Ultrasonic receiving unit

116, 416‧‧‧ first adhesive layer

1122, 2122, 4122 ‧‧‧ first emitter electrode

1124‧‧‧Second emitter electrode

1126, 3126‧‧‧‧piezoelectric emission layer

1142‧‧‧First receiving electrode

1144, 4144‧‧‧Second receiving electrode

1146, 3146, 4146‧‧‧ Piezoelectric receiving layer

120, 220, 320, 420‧‧‧ flexible circuit boards

120a, 220a, 320a‧‧‧ first surface

120b, 220b, 320b‧‧‧Second surface

122, 322‧‧‧ Part I

124, 224, 324‧‧‧ Part II

126‧‧‧Part III

128‧‧‧ pad

129‧‧‧Terminal

130, 230, 330‧‧‧ platen

500‧‧‧ electronic device

510a‧‧‧front

500b‧‧‧ back

510‧‧‧display area

no

Claims (11)

An ultrasonic sensor includes an ultrasonic transceiver, a flexible circuit board, and a pressure plate. The ultrasonic transceiver and the flexible circuit board are disposed on the same side of the pressure plate. The improvement is that the ultrasonic wave The transceiver includes an ultrasonic transmitting unit and an ultrasonic receiving unit that are stacked on top of each other. The flexible circuit board is electrically connected to the ultrasonic transmitting unit and the ultrasonic receiving unit. The ultrasonic sensor according to claim 1, wherein the ultrasonic transmitting unit and the ultrasonic receiving unit are bonded by a first adhesive layer. The ultrasonic sensor according to claim 2, wherein the ultrasonic transmitting unit includes a first transmitting electrode, a second transmitting electrode, and the first transmitting electrode and the second transmitting electrode. Between the piezoelectric emission layer, the second emission electrode is disposed on a side of the piezoelectric emission layer away from the ultrasonic wave receiving unit and is electrically connected to the flexible circuit board, and the first emission electrode is disposed on The piezoelectric emitting layer is close to one side of the ultrasonic wave receiving unit and is bent to a surface of the piezoelectric emitting layer on which the second emitting electrode is disposed and is electrically connected to the flexible circuit board. The ultrasonic sensor according to claim 2, wherein the ultrasonic transmitting unit includes a first transmitting electrode, a second transmitting electrode, and the first transmitting electrode and the second transmitting electrode. Between the piezoelectric emission layer, the first emission electrode is disposed on a side of the piezoelectric emission layer close to the ultrasonic receiving unit, and the second emission electrode is disposed on the piezoelectric emission layer away from the ultrasound On the side of the sound wave receiving unit, the second emitting electrode is electrically connected to the flexible circuit board, and the first emitting electrode and the second emitting electrode are respectively disposed on different surfaces on both sides of the piezoelectric emitting layer. . The ultrasonic sensor according to claim 3 or 4, wherein the ultrasonic receiving unit includes a first receiving electrode and a second receiving electrode, and the first receiving electrode and the second receiving electrode are disposed on the first receiving electrode and the second receiving electrode. A piezoelectric receiving layer between receiving electrodes; the second receiving electrode is disposed on a side of the piezoelectric receiving layer away from the ultrasonic transmitting unit and is electrically connected to the flexible circuit board; the first receiving electrode The piezoelectric receiving layer is disposed on a side of the piezoelectric receiving layer near the ultrasonic transmitting unit and is bent to a surface of the piezoelectric receiving electrode on which the second receiving electrode is provided and is electrically connected to the flexible circuit board. The ultrasonic sensor according to claim 5, wherein the first adhesive layer has conductivity. The ultrasonic sensor according to claim 3, wherein the ultrasonic receiving unit includes a first receiving electrode and a second receiving electrode, and is disposed between the first receiving electrode and the second receiving electrode A piezoelectric receiving layer, the first receiving electrode is disposed on a side of the piezoelectric receiving layer near the ultrasonic transmitting unit, and the second receiving electrode is disposed on the piezoelectric receiving layer away from the ultrasonic transmitting On the unit side, the second receiving electrode is electrically connected to the flexible circuit board, and the first receiving electrode and the second receiving electrode are respectively disposed on different surfaces on both sides of the piezoelectric receiving layer. The ultrasonic sensor according to claim 5 or 7, wherein the first transmitting electrode and the second transmitting electrode are electrically connected to the flexible circuit board through a second adhesive layer; the first A receiving electrode and the second receiving electrode are electrically connected to the flexible circuit board through a second adhesive layer, and the second adhesive layer is conductive. The ultrasonic sensor according to claim 5 or 7, wherein the size of the piezoelectric emitting layer is larger than that of the piezoelectric receiving layer. The ultrasonic sensor according to claim 1, wherein one end of the flexible circuit board is disposed between the ultrasonic transceiver and the pressure plate, and the other end is wound along the ultrasonic transceiver so that all The flexible circuit board surrounds at least three adjacent sides of the ultrasonic transceiver. An electronic device includes the ultrasonic sensor according to any one of claims 1-10.