Ultrasonic detection module, manufacturing method, driving method and display device

Abstract

The present invention discloses an ultrasonic detection module, a manufacturing method, a driving method and a display device, wherein the ultrasonic detection module of one embodiment includes a detection circuit and an ultrasonic sensor stacked in sequence on a substrate, wherein the ultrasonic sensor is used to emit ultrasonic waves, receive reflected ultrasonic waves and output a first electrical signal; the detection circuit includes a reset unit, a transmission holding unit, a storage unit and a reading unit, wherein the detection circuit receives the first electrical signal in response to a reset control signal received by the reset unit and a transmission holding control signal received by the transmission holding unit, and stores the first electrical signal in the storage unit through the transmission holding unit and holds it for a preset time, and reads the second electrical signal output by the transmission holding unit in response to a read control signal received by the reading unit; the reset unit, the storage unit and the reading unit are low-temperature polysilicon thin-film transistors, and the transmission holding unit is a metal oxide thin-film transistor.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to an ultrasonic detection module, a manufacturing method, a driving method and a display device. Background Art

[0002] In recent years, ultrasonic sensors have been widely used in the consumer electronics, automotive, industrial, and medical fields. In the consumer electronics and medical fields, they are mainly used as ultrasonic imaging sensors for fingerprint recognition, gesture recognition, and ultrasonic imaging.

[0003] The clarity of sensor imaging determines the user experience. For example, in the field of medical testing, the higher the imaging quality, the more accurate the diagnosis of the patient's condition and the more appropriate medical treatment can be. Therefore, improving the clarity of ultrasonic sensors has become an urgent problem to be solved. Summary of the Invention

[0004] In order to solve at least one of the above problems, the first embodiment of the present invention provides an ultrasonic detection module, comprising a detection circuit and an ultrasonic sensor stacked in sequence on a substrate, wherein:

[0005] The ultrasonic sensor is configured to transmit ultrasonic waves, receive reflected ultrasonic waves, and output a first electrical signal;

[0006] The detection circuit includes a reset unit, a transmission holding unit, a storage unit, and a reading unit, wherein the detection circuit receives the first electrical signal in response to a reset control signal received by the reset unit and a transmission holding control signal received by the transmission holding unit, stores the first electrical signal through the transmission holding unit and holds it in the storage unit for a preset time, and reads the second electrical signal output by the transmission holding unit in response to a read control signal received by the reading unit;

[0007] The reset unit, storage unit and reading unit are low-temperature polysilicon thin film transistors, and the transmission holding unit is a metal oxide thin film transistor.

[0008] For example, in the ultrasonic detection module provided in some embodiments of the present application, the reset unit, the transmission holding unit, the storage unit, and the reading unit each include a first end, a second end, and a control end;

[0009] The first end of the reset unit and the first end of the transmission holding unit are connected to a first node, the second end of the reset unit is connected to a reset voltage, the control end of the reset unit is connected to the reset control signal, and the reset unit sets the first node to the reset voltage in response to the reset control signal;

[0010] The first end of the transmission holding unit and the first end of the ultrasonic sensor are connected to the first node, the second end of the transmission holding unit is connected to the control end of the storage unit, the control end of the transmission holding unit is connected to the transmission holding control signal, and under the control of the reset control signal, the transmission holding unit transmits the first electrical signal output by the first end of the ultrasonic sensor from the first end of the transmission holding unit to the second end of the transmission holding unit to transmit it to the control end of the storage unit in response to the transmission holding control signal;

[0011] The first end of the storage unit is connected to the first power signal, the second end of the storage unit is connected to the first end of the reading unit, and the storage unit amplifies the first electrical signal and outputs the second electrical signal;

[0012] The second end of the reading unit is connected to the reading line, the control end of the reading unit receives the reading control signal, and the reading unit transmits the second electrical signal from the first end of the reading unit to the second end of the reading unit in response to the reading control signal.

[0013] For example, in the ultrasonic detection module provided in some embodiments of the present application, the detection circuit includes:

[0014] A patterned first active material layer is provided on the substrate, wherein the first active material layer includes an active layer of the reset unit, an active layer of the storage unit, and an active layer of the read unit provided on the same layer;

[0015] a first gate insulating layer covering the first active material layer and the exposed portion of the substrate;

[0016] a patterned first gate material layer disposed on the first gate insulating layer, wherein the first gate material layer includes a gate of the reset unit, a gate of the storage unit, and a gate of the read unit disposed on the same layer;

[0017] a first interlayer insulating layer covering the first gate material layer and the exposed first gate insulating layer;

[0018] a patterned second active material layer disposed on the first interlayer insulating layer, wherein the second active material layer is an active layer of the transmission maintaining unit;

[0019] a second gate insulating layer covering the second active material layer and the exposed first interlayer insulating layer;

[0020] a patterned second gate material layer disposed on the second gate insulating layer, wherein the second gate material layer serves as a gate of the transmission holding unit;

[0021] a second interlayer insulating layer covering the second gate material layer and the exposed second gate insulating layer;

[0022] a patterned first metal layer disposed on the second interlayer insulating layer, the first metal layer including a source and a drain of the reset unit, a source and a drain of the transmission holding unit, a source and a drain of the storage unit, and a source and a drain of the reading unit, and a first connection metal disposed on the same layer, the source and the drain being connected to the corresponding active layer through vias, and the first connection metal being connected to the gate of the storage unit through the via;

[0023] a first inorganic layer covering the first metal layer and the exposed second interlayer insulating layer;

[0024] a patterned second metal layer disposed on the first inorganic layer, the second metal layer being connected to the drain electrode of the transmission holding unit and the first connection metal through corresponding vias; and

[0025] A second inorganic layer covers the second metal layer and the exposed first inorganic layer.

[0026] For example, in the ultrasonic detection module provided in some embodiments of the present application, the ultrasonic sensor includes:

[0027] a first electrode reused by the second metal layer;

[0028] a piezoelectric material layer covering the second inorganic layer; and

[0029] A second electrode covers the piezoelectric material layer.

[0030] For example, in the ultrasonic detection module provided in some embodiments of the present application, the reset unit, the transmission holding unit, the storage unit, and the reading unit each include a first end, a second end, and a control end;

[0031] The first end of the reset unit and the first end of the transmission holding unit are connected to a second node, the second end of the reset unit is connected to a reset voltage, the control end of the reset unit is connected to the reset control signal, and the reset unit sets the second node to the reset voltage in response to the reset control signal;

[0032] The first end of the transmission holding unit and the first end of the ultrasonic sensor are connected to the second node, the second end of the transmission holding unit is connected to the first end of the storage unit, the control end of the transmission holding unit is connected to the transmission holding control signal, and under the control of the reset control signal, the transmission holding unit transmits the first electrical signal output by the first end of the ultrasonic sensor from the first end of the transmission holding unit to the second end of the transmission holding unit to transmit it to the first end of the storage unit in response to the transmission holding control signal;

[0033] The second end of the storage unit is connected to the first end of the reading unit, the control end of the storage unit is connected to the storage control signal, and the storage unit transmits the first electrical signal to the second end of the storage unit in response to the storage control signal and outputs the first electrical signal as the second electrical signal;

[0034] The second end of the reading unit is connected to the reading line, the control end of the reading unit receives the reading control signal, and the reading unit transmits the second electrical signal from the first end of the reading unit to the second end of the reading unit in response to the reading control signal.

[0035] For example, in the ultrasonic detection module provided in some embodiments of the present application, the detection circuit includes:

[0036] a patterned third active material layer disposed on the substrate, the third active material layer comprising an active layer of the reset unit, an active layer of the storage unit, and an active layer of the read unit disposed on the same layer;

[0037] a third gate insulating layer covering the third active material layer and the exposed portion of the substrate;

[0038] a patterned third gate material layer disposed on the third gate insulating layer, wherein the third gate material layer includes a gate of the reset unit, a gate of the storage unit, and a gate of the read unit disposed on the same layer;

[0039] a third interlayer insulating layer covering the third gate material layer and the exposed third gate insulating layer;

[0040] a patterned fourth active material layer disposed on the third interlayer insulating layer, wherein the fourth active material layer is an active layer of the transmission maintaining unit;

[0041] a fourth gate insulating layer covering the fourth active material layer and the exposed third interlayer insulating layer;

[0042] a patterned fourth gate material layer disposed on the fourth gate insulating layer, wherein the fourth gate material layer serves as a gate of the transmission holding unit;

[0043] a fourth interlayer insulating layer covering the fourth gate material layer and the exposed fourth gate insulating layer;

[0044] A patterned third metal layer is provided on the fourth interlayer insulating layer, the third metal layer including a source and a drain of the reset unit, a source and a drain of the transmission holding unit, a source and a drain of the storage unit, and a source and a drain of the reading unit provided on the same layer, the source and the drain being connected to the corresponding active layer through vias;

[0045] a third inorganic layer covering the third metal layer and the exposed fourth interlayer insulating layer;

[0046] a patterned fourth metal layer disposed on the third inorganic layer, the fourth metal layer being connected to the drain of the transmission holding unit and the source of the storage unit through corresponding vias; and

[0047] A fourth inorganic layer covers the fourth metal layer and the exposed third inorganic layer.

[0048] For example, in the ultrasonic detection module provided in some embodiments of the present application, the ultrasonic sensor includes:

[0049] a first electrode reused by the fourth metal layer;

[0050] a piezoelectric material layer covering the fourth inorganic layer; and

[0051] A second electrode covers the piezoelectric material layer.

[0052] For example, in some embodiments of the present application, the ultrasonic detection module further includes a protective insulating layer covering the ultrasonic sensor, and the acoustic impedance of the protective insulating layer, the acoustic impedance of the second electrode, and the acoustic impedance of the piezoelectric material layer of the ultrasonic sensor are matched.

[0053] For example, in the ultrasonic detection module provided in some embodiments of the present application, the thickness of the piezoelectric material layer of the ultrasonic sensor is:

[0054]

[0055] Wherein, f0 is the resonant frequency of the ultrasonic wave, n is the frequency order, E is the Young's modulus of the piezoelectric material layer, and ρ is the density of the piezoelectric material layer.

[0056] A second embodiment of the present invention provides a method for manufacturing the ultrasonic detection module as described in the first embodiment, comprising:

[0057] A detection circuit is formed on a substrate, the detection circuit comprising a reset unit, a transmission and holding unit, a storage unit, and a reading unit, wherein the detection circuit receives a first electrical signal output by an ultrasonic sensor in response to a reset control signal received by the reset unit and a transmission and holding control signal received by the transmission and holding unit, stores the first electrical signal through the transmission and holding unit and holds it in the storage unit for a preset time, and reads a second electrical signal output by the transmission and holding unit in response to a read control signal received by the reading unit, the reset unit, the storage unit, and the reading unit being low-temperature polysilicon thin-film transistors, and the transmission and holding unit being a metal oxide thin-film transistor;

[0058] An ultrasonic sensor for transmitting ultrasonic waves, receiving returned ultrasonic waves, and outputting the first electrical signal is formed on the detection circuit.

[0059] For example, in the manufacturing methods provided in some embodiments of the present application, forming a detection circuit on a substrate further includes:

[0060] forming a patterned first active material layer on the substrate, wherein the first active material layer includes an active layer of the reset unit, an active layer of the storage unit, and an active layer of the read unit arranged on the same layer;

[0061] forming a first gate insulating layer covering the first active material layer and the exposed portion of the substrate;

[0062] forming a patterned first gate material layer on the first gate insulating layer, wherein the first gate material layer includes a gate of the reset unit, a gate of the storage unit, and a gate of the read unit arranged in the same layer;

[0063] forming a first interlayer insulating layer covering the first gate material layer and the exposed first gate insulating layer;

[0064] forming a patterned second active material layer on the first interlayer insulating layer, wherein the second active material layer is an active layer of the transmission maintaining unit;

[0065] forming a second gate insulating layer covering the second active material layer and the exposed first interlayer insulating layer;

[0066] forming a patterned second gate material layer on the second gate insulating layer, wherein the second gate material layer serves as a gate of the transmission holding unit;

[0067] forming a second interlayer insulating layer covering the second gate material layer and the exposed second gate insulating layer;

[0068] forming a patterned first metal layer on the second interlayer insulating layer, the first metal layer including a source and a drain of the reset unit, a source and a drain of the transmission holding unit, a source and a drain of the storage unit, and a source and a drain of the reading unit, and a first connection metal, the source and the drain being connected to the corresponding active layer through vias, and the first connection metal being connected to the gate of the storage unit through the via;

[0069] forming a first inorganic layer covering the first metal layer and the exposed second interlayer insulating layer;

[0070] A patterned second metal layer is formed on the first inorganic layer, the second metal layer being connected to the drain of the transmission holding unit and the first connection metal through corresponding vias; and a second inorganic layer is formed covering the second metal layer and exposing the first inorganic layer.

[0071] The ultrasonic sensor formed on the detection circuit for transmitting ultrasonic waves, receiving returned ultrasonic waves and outputting the first electrical signal further includes:

[0072] reusing the second metal layer as a first electrode;

[0073] forming a piezoelectric material layer covering the second inorganic layer; and

[0074] A second electrode is formed covering the piezoelectric material layer.

[0075] For example, in the manufacturing methods provided in some embodiments of the present application, forming a detection circuit on a substrate further includes:

[0076] forming a patterned third active material layer on the substrate, wherein the third active material layer includes an active layer of the reset unit, an active layer of the storage unit, and an active layer of the read unit arranged on the same layer;

[0077] forming a third gate insulating layer covering the third active material layer and the exposed portion of the substrate;

[0078] forming a patterned third gate material layer on the third gate insulating layer, wherein the third gate material layer includes a gate of the reset unit, a gate of the storage unit, and a gate of the read unit arranged on the same layer;

[0079] forming a third interlayer insulating layer covering the third gate material layer and the exposed third gate insulating layer;

[0080] forming a patterned fourth active material layer on the third interlayer insulating layer, wherein the fourth active material layer is an active layer of the transmission maintaining unit;

[0081] forming a fourth gate insulating layer covering the fourth active material layer and the exposed third interlayer insulating layer;

[0082] forming a patterned fourth gate material layer on the fourth gate insulating layer, wherein the fourth gate material layer serves as the gate of the transmission holding unit;

[0083] forming a fourth interlayer insulating layer covering the fourth gate material layer and the exposed fourth gate insulating layer;

[0084] forming a patterned third metal layer on the fourth interlayer insulating layer, the third metal layer including a source and a drain of the reset unit, a source and a drain of the transmission holding unit, a source and a drain of the storage unit, and a source and a drain of the reading unit, the source and the drain being connected to the corresponding active layer through vias;

[0085] forming a third inorganic layer covering the third metal layer and the exposed fourth interlayer insulating layer;

[0086] forming a patterned fourth metal layer on the third inorganic layer, wherein the fourth metal layer is respectively connected to the drain of the transmission holding unit and the source of the storage unit through corresponding via holes; and

[0087] forming a fourth inorganic layer covering the fourth metal layer and exposing the third inorganic layer

[0088] The ultrasonic sensor formed on the detection circuit for transmitting ultrasonic waves, receiving returned ultrasonic waves and outputting the first electrical signal further includes:

[0089] Reusing the fourth metal layer as a first electrode;

[0090] forming a piezoelectric material layer covering the fourth inorganic layer; and

[0091] A second electrode is formed covering the piezoelectric material layer.

[0092] For example, in the manufacturing method provided in some embodiments of the present application, after forming an ultrasonic sensor on the detection circuit for emitting ultrasonic waves, receiving returned ultrasonic waves and outputting the first electrical signal, it also includes: forming a protective insulating layer covering the ultrasonic sensor, and matching the acoustic impedance of the protective insulating layer, the acoustic impedance of the second electrode, and the acoustic impedance of the piezoelectric material layer of the ultrasonic sensor.

[0093] A third embodiment of the present invention provides a driving method using the ultrasonic detection module described in the first embodiment, comprising:

[0094] In the transmitting stage, in response to the reset control signal received by the reset unit, the first terminal of the ultrasonic sensor is set to a reset voltage, and the ultrasonic sensor transmits ultrasonic waves according to the input signal inputted at the second terminal thereof;

[0095] In the reading stage, in response to the reset control signal received by the reset unit and the transmission and holding control signal received by the transmission and holding unit, the ultrasonic sensor receives the reflected ultrasonic wave, the first end of the ultrasonic sensor outputs a first electrical signal, the first electrical signal is stored by the transmission and holding unit and is held in the storage unit for a preset time, and the second electrical signal output by the storage unit is read in response to the read control signal received by the reading unit.

[0096] The fourth embodiment of the present invention provides an under-screen ultrasonic imaging display device, comprising a display panel and the ultrasonic detection module described in the first embodiment, wherein

[0097] The display panel includes a substrate and a display substrate arranged on the substrate;

[0098] The side of the substrate of the ultrasonic detection module away from the ultrasonic sensor and the side of the substrate of the display panel away from the display substrate are attached by adhesive.

[0099] The beneficial effects of the present invention are as follows:

[0100] In response to the current problems, the present invention develops an ultrasonic detection module, a manufacturing method, a driving method and a display device. The ultrasonic detection module uses a detection circuit to detect a first electrical signal output by an ultrasonic sensor, and ensures that the first electrical signal is stored and maintained in a storage unit according to a preset time by using a transmission holding unit formed by a metal oxide thin film transistor. That is, the small leakage current characteristic of the metal oxide thin film transistor is used to keep the first electrical signal stably stored in the storage unit, thereby improving the detection accuracy of the ultrasonic detection module, especially improving the detection accuracy and stability of large-area, high-pixel-density ultrasonic detection modules, thereby compensating for the problems existing in the existing technology and having broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0101] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0102] Figure 1 A structural block diagram of an ultrasonic detection module according to an embodiment of the present invention is shown;

[0103] Figure 2 A circuit diagram of an ultrasonic detection module according to an embodiment of the present invention is shown;

[0104] Figure 3 A timing diagram showing the operation of the ultrasonic detection module according to one embodiment of the present invention is shown;

[0105] Figure 4 A schematic structural diagram of an ultrasonic detection module according to an embodiment of the present invention is shown;

[0106] Figure 5 A circuit diagram of an ultrasonic detection module according to another embodiment of the present invention is shown;

[0107] Figure 6 A timing diagram showing the operation of the ultrasonic detection module according to another embodiment of the present invention is shown;

[0108] Figure 7 A schematic structural diagram of an ultrasonic detection module according to another embodiment of the present invention is shown;

[0109] Figures 8a-8b A schematic structural diagram of a display device according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0110] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the following detailed description is illustrative rather than restrictive and should not be used to limit the scope of protection of the present invention.

[0111] It should be noted that the terms “on…”, “formed on…” and “disposed on…” herein may indicate that one layer is directly formed or disposed on another layer, or may indicate that one layer is indirectly formed or disposed on another layer, i.e., there are other layers between the two layers. In this article, unless otherwise specified, the term “located on the same layer” means that two layers, parts, components, elements or parts can be formed by the same patterning process, and that the two layers, parts, components, elements or parts are generally formed of the same material. In this article, unless otherwise specified, the expression “patterning process” generally includes steps such as coating, exposure, development, etching, and stripping of the photoresist. The expression “one-time patterning process” means a process of forming patterned layers, parts, components, etc. using a mask.

[0112] Currently, the market demand for ultrasonic sensors is significant. Consulting firms predict that demand will grow by 5% over the next five years, with the medical sector accounting for the largest share of demand. Currently, ultrasonic sensors are implemented in three main ways: PMUT (micro piezoelectric ultrasonic transducers), CMUT (micro capacitive ultrasonic transducers), and sandwich piezoelectric sensor structures. Ultrasonic imaging, such as medical imaging and fingerprint recognition, typically uses an ultrasonic frequency band of approximately 5-10 MHz.

[0113] Since both micro piezoelectric ultrasonic sensors PMUT and micro capacitive ultrasonic sensors CMUT require the preparation of cavity structures for resonance and the processing technology is relatively difficult, the sandwich piezoelectric ultrasonic sensing structure has always been the mainstream direction of the ultrasonic sensor market.

[0114] The primary piezoelectric material used in current sandwich ultrasonic sensors is piezoelectric ceramics. While these materials have high dielectric constants and piezoelectric constants, they require high processing temperatures, requiring sintering and grinding at 600-800°C. Organic PVDF polymers, on the other hand, have a piezoelectric constant of 22pC / N and can be formed into films over large areas, making them easy to manufacture into large-scale ultrasonic sensors. However, existing piezoelectric ultrasonic sensors suffer from small imaging areas and fuzzy image quality.

[0115] In response to the above situation, the inventors have proposed through extensive research and experiments that the reason for the shortcomings of piezoelectric ultrasonic sensor devices is that the ultrasonic signals received by the ultrasonic sensor devices are weak, and the quality of the final imaging processed by the sensor is poor.

[0116] According to the above problems and the causes of the problems, such as Figure 1 As shown, an embodiment of the present invention provides an ultrasonic detection module, comprising a detection circuit and an ultrasonic sensor stacked sequentially on a substrate, wherein:

[0117] The ultrasonic sensor is configured to transmit ultrasonic waves, receive reflected ultrasonic waves, and output a first electrical signal;

[0118] The detection circuit includes a reset unit, a transmission holding unit, a storage unit, and a reading unit, wherein the detection circuit receives the first electrical signal in response to a reset control signal received by the reset unit and a transmission holding control signal received by the transmission holding unit, stores the first electrical signal through the transmission holding unit and holds it in the storage unit for a preset time, and reads the second electrical signal output by the transmission holding unit in response to a read control signal received by the reading unit;

[0119] The reset unit, storage unit and reading unit are low-temperature polysilicon thin film transistors, and the transmission holding unit is a metal oxide thin film transistor.

[0120] This embodiment uses a detection circuit to detect the first electrical signal output by the ultrasonic sensor, and ensures that the first electrical signal is stored and maintained in the storage unit according to a preset time by using a transmission holding unit formed by a metal oxide thin film transistor, that is, the small leakage current characteristic of the metal oxide thin film transistor is used to keep the first electrical signal stably stored in the storage unit, thereby improving the detection accuracy of the ultrasonic detection module, especially the detection accuracy and stability of large-area, high-pixel-density ultrasonic detection modules, thereby compensating for the problems existing in the existing technology and having broad application prospects.

[0121] In a specific example, Figure 2 The figure shows a circuit diagram of an ultrasonic detection module, wherein the reset unit T1, the transmission holding unit T2, the storage unit T3 and the reading unit T4 each include a first end, a second end and a control end;

[0122] The first end of the reset unit T1 and the first end of the transmission holding unit T2 are connected to the first node N1, the second end of the reset unit T2 is connected to the reset voltage Reset, the control end of the reset unit T2 is connected to the reset control signal, and the reset unit T2 sets the first node N1 to the reset voltage in response to the reset control signal;

[0123] The first end of the transmission holding unit T2 and the first end of the ultrasonic sensor PVDF are connected to the first node N1, the second end of the transmission holding unit T2 is connected to the control end of the storage unit T3, the control end of the transmission holding unit T2 is connected to the transmission holding control signal, and under the control of the reset control signal, the transmission holding unit T2 transmits the first electrical signal output from the first end of the ultrasonic sensor PVDF from the first end of the transmission holding unit T2 to the second end of the transmission holding unit T2 so as to transmit it to the control end of the storage unit T3;

[0124] The first end of the storage unit T3 is connected to the first power signal AP, the second end of the storage unit T3 is connected to the first end of the reading unit T4, and the storage unit T3 amplifies the first electrical signal and outputs the second electrical signal;

[0125] The second end of the reading unit T4 is connected to the reading line Dn, the control end of the reading unit T4 is connected to the reading control signal, and the reading unit T4 transmits the second electrical signal from the first end of the reading unit T4 to the second end of the reading unit T4 in response to the reading control signal.

[0126] like Figure 3 The following is a timing diagram of this embodiment. The working process of the ultrasonic detection module is as follows:

[0127] In the transmitting phase t0-t1, the detection circuit sets the first terminal of the ultrasonic sensor PVDF to the reset voltage Reset in response to the reset control signal received by the reset unit T1, and the ultrasonic sensor PVDF transmits ultrasonic waves according to the input signal inputted at its second terminal.

[0128] In this embodiment, in the transmission stage, the reset control signal and the transmission hold control signal are valid signals, the reset unit T1 and the transmission hold unit T2 are closed, the reset voltage Reset is at a low level, the first node N1 is the reset voltage, the control end of the storage unit T3 is the reset voltage, and the ultrasonic sensor PVDF transmits ultrasonic waves according to the received input signal.

[0129] In the reading phase t1-t4, the detection circuit responds to the reset control signal received by the reset unit and the transmission and holding control signal received by the transmission and holding unit, the ultrasonic sensor receives the reflected ultrasonic wave, the first end of the ultrasonic sensor outputs a first electrical signal, the first electrical signal is stored by the transmission and holding unit and is held in the storage unit for a preset time, and the second electrical signal output by the storage unit is read in response to the read control signal received by the reading unit.

[0130] In this embodiment, the reading phase is further divided into the following phases:

[0131] In the receiving sampling phase t1-t2, the reset control signal is an invalid signal, the reset unit T1 is disconnected, the transmission holding control signal is a valid signal, the transmission holding unit T2 is turned on, the ultrasonic sensor PVDF receives the reflected ultrasonic wave and outputs a first electrical signal, and the control end of the storage unit T3 is charged according to the received first electrical signal. When the threshold voltage of the storage unit T3 is met, the storage unit T3 is closed.

[0132] During the hold phase t2-t3, the ultrasonic sensor stops receiving the reflected ultrasonic wave and ceases to output the first electrical signal. The reset control signal and the transmission hold control signal are inactive, and reset unit T1 and transmission hold unit T2 are disconnected. Because transmission hold unit T2 is a metal oxide thin film transistor with low leakage current, it maintains the control terminal of storage unit T3, effectively storing and retaining the first electrical signal in the storage unit for a predetermined period of time.

[0133] During the readout phase t3-t4, the reset control signal and the transmission hold control signal are inactive, reset unit T1 is disconnected, and transmission hold unit T2 is disconnected. The control terminal of storage unit T3 holds the first electrical signal, and storage unit T3 is closed. The readout control signal is active, and readout unit T4 is closed, reading the second electrical signal output by the storage unit to readout line Dn. It is worth noting that storage unit T3 operates in an amplification state, amplifying the first electrical signal and outputting a second electrical signal. Readout unit T4 then reads the second electrical signal.

[0134] like Figure 4 FIG. 1 is a schematic diagram of the structure of this embodiment. The ultrasonic detection module includes an ultrasonic sensor PVDF21 and a detection circuit. The detection circuit includes:

[0135] A patterned first active material layer is provided on the substrate 10, wherein the first active material layer includes an active layer 27 of the reset unit T1, the storage unit T3 and the read unit T4 provided on the same layer;

[0136] a first gate insulating layer 13 covering the first active material layer and the exposed portion of the substrate 10;

[0137] a patterned first gate material layer disposed on the first gate insulating layer 13 , wherein the first gate material layer includes gates 26Gate1 of the reset unit T1 , the storage unit T3 , and the read unit T4 disposed on the same layer;

[0138] a first interlayer insulating layer 14 covering the first gate material layer and the exposed first gate insulating layer 13;

[0139] A patterned second active material layer is provided on the first interlayer insulating layer 14 , wherein the second active material layer is the active layer 25IGZO of the transmission maintaining unit T2 ;

[0140] a second gate insulating layer 16 covering the second active material layer and the exposed first interlayer insulating layer 14;

[0141] a patterned second gate material layer disposed on the second gate insulating layer 16 , wherein the second gate material layer is the gate 24Gate2 of the transmission holding unit T2 ;

[0142] a second interlayer insulating layer 17 covering the second gate material layer and the exposed second gate insulating layer 16;

[0143] A patterned first metal layer is provided on the second interlayer insulating layer 17, the first metal layer including a source S and a drain D of the reset unit T1, a source S and a drain D of the transmission holding unit T2, a source S and a drain D of the storage unit T3, and a source S and a drain D of the reading unit T4, and a first connection metal SD provided on the same layer, the source S and the drain D being connected to the corresponding active layer through a via, and the first connection metal SD being connected to the gate Gate1 of the storage unit T3 through a via;

[0144] a first inorganic layer 18 covering the first metal layer and the exposed second interlayer insulating layer 17;

[0145] a patterned second metal layer SD2 disposed on the first inorganic layer 18 , the second metal layer being connected to the drain electrode D of the transmission maintaining unit T2 and the first connection metal SD through corresponding vias; and

[0146] A second inorganic layer 19 covers the second metal layer SD2 and the exposed first inorganic layer 18 .

[0147] In this embodiment, a transmission holding unit formed by using a metal oxide thin film transistor is used to ensure that the first electrical signal is stored and maintained in the storage unit according to a preset time. That is, the small leakage current characteristic of the metal oxide thin film transistor is utilized to keep the first electrical signal stably stored in the storage unit, thereby improving the detection accuracy of the ultrasonic detection module, and especially improving the detection accuracy and stability of the ultrasonic detection module with a large area and high pixel density.

[0148] like Figure 4 As shown, the production process of the ultrasonic detection module is used to illustrate:

[0149] First, a detection circuit is formed on a substrate, specifically including:

[0150] In the first step, a patterned first active material layer is formed on the substrate 10 , wherein the first active material layer includes the active layer of the reset unit T1 , the active layer of the storage unit T3 , and the active layer 27 of the read unit T4 arranged on the same layer.

[0151] In this embodiment, a barrier layer 11 and a buffer layer 12 of a certain thickness are deposited on a substrate 10 by a plasma enhanced chemical vapor deposition (PECVD) device, and then an active material layer of a certain thickness is deposited on the buffer layer 12 by a PECVD device, and patterned by photolithography and etching processes to form an active layer 27 of the reset unit T1, the storage unit T3 and the read unit T4, and then the a-Si of the active layer is lightly doped by excimer laser crystallization (ELA) to change the crystal lattice to form polysilicon.

[0152] In the second step, a first gate insulating layer 13 is formed to cover the first active material layer and the exposed portion of the substrate 10 .

[0153] In this embodiment, silicon oxide SiO having a certain thickness is deposited as the first gate insulating layer 13 by using a PECVD device.

[0154] In the third step, a patterned first gate material layer is formed on the first gate insulating layer, wherein the first gate material layer includes the gate of the reset unit, the gate of the storage unit, and the gate of the read unit arranged on the same layer.

[0155] In this embodiment, a certain thickness of metal is deposited as a first gate material layer by sputtering equipment, and patterned by photolithography and etching processes to form the gates 26 of the reset unit T1 , the storage unit T3 , and the read unit T4 .

[0156] It is worth noting that, in this embodiment, the active layer is further heavily doped to reduce the contact resistance between the source and drain of the subsequent reset unit T1 , storage unit T3 and read unit T4 and the active layer, thereby improving the connection effect.

[0157] The fourth step is to form a first interlayer insulating layer covering the first gate material layer and the exposed first gate insulating layer.

[0158] In this embodiment, the first interlayer insulating layer 14 and the buffer layer 15 are deposited to a certain thickness by using a PECVD device.

[0159] In a fifth step, a patterned second active material layer is formed on the first interlayer insulating layer, where the second active material layer is the active layer of the transmission maintaining unit.

[0160] In this embodiment, a second active material layer IGZO having a certain thickness is deposited by a Sputter device, and is patterned by photolithography and etching processes to form the active layer 25 of the transmission maintaining unit T2 .

[0161] In a sixth step, a second gate insulating layer is formed to cover the second active material layer and the exposed first interlayer insulating layer.

[0162] In this embodiment, SiO with a certain thickness is deposited as the second gate insulating layer 16 by using a PECVD device.

[0163] In the seventh step, a patterned second gate material layer is formed on the second gate insulating layer, where the second gate material layer serves as the gate of the transmission holding unit.

[0164] In this embodiment, a metal layer of a certain thickness is deposited as the second gate material layer by a Sputter device, and patterned by photolithography and etching processes to form the gate 24 of the transmission holding unit T2.

[0165] In the eighth step, a second interlayer insulating layer is formed to cover the second gate material layer and the exposed second gate insulating layer.

[0166] In this embodiment, the second interlayer insulating layer 17 with a certain thickness is deposited by PECVD equipment.

[0167] The ninth step is to form a patterned first metal layer on the second interlayer insulating layer, wherein the first metal layer includes the source and drain of the reset unit, the source and drain of the transmission holding unit, the source and drain of the storage unit, and the source and drain of the reading unit, as well as a first connecting metal, the source and drain are connected to the corresponding active layer through vias, and the first connecting metal is connected to the gate of the storage unit through vias.

[0168] In this embodiment, a first metal layer of Ti / Al / Ti metal of a certain thickness is deposited by a Sputter device, and patterned by photolithography and etching processes to form the source S and drain D of the reset unit T1, the source S and drain D of the transmission holding unit T2, the source S and drain D of the storage unit T3, the source S and drain D of the read unit T4, and the first connection metal SD.

[0169] In the tenth step, a first inorganic layer is formed to cover the first metal layer and the exposed second interlayer insulating layer.

[0170] In this embodiment, the first inorganic layer 18 is deposited to a certain thickness by using a PECVD device.

[0171] In the eleventh step, a patterned second metal layer is formed on the first inorganic layer, wherein the second metal layer is respectively connected to the drain of the transmission holding unit and the first connection metal through corresponding via holes.

[0172] In this embodiment, a certain thickness of ITO metal is deposited by a Sputter device and patterned by photolithography and etching processes to form a second metal layer SD2. The second metal layer SD2 is connected to the drain D of the transmission holding unit T2 and the first connection metal SD through corresponding vias.

[0173] In an optional embodiment, the second metal layer is reused as the first electrode of the ultrasonic sensor.

[0174] In this embodiment, the second metal layer of the detection circuit is reused as the first electrode of the ultrasonic sensor, which effectively reduces the thickness of the ultrasonic detection module.

[0175] In the twelfth step, a second inorganic layer is formed to cover the second metal layer and expose the first inorganic layer.

[0176] In this embodiment, silicon nitride SiN having a certain thickness is deposited as the second inorganic layer 19 by using PECVD equipment.

[0177] In the thirteenth step, a piezoelectric material layer is formed covering the second inorganic layer.

[0178] In this embodiment, a PVDF solution of a certain thickness is applied by spin coating, crystallized, and solidified. A Mo / AlNd / Mo metal layer of a certain thickness is then deposited at low temperature as a hard mask to pattern the PVDF using a dry etching process. Finally, a polarization process is performed to impart piezoelectric properties to the PVDF to form a piezoelectric material layer 20.

[0179] Step 14: forming a second electrode covering the piezoelectric material layer.

[0180] In this embodiment, a silver paste having a certain thickness is coated by a screen printing process as the second electrode 21 of the sandwich piezoelectric sensor device structure.

[0181] In the fifteenth step, a protective insulating layer is formed to cover the ultrasonic sensor, and the acoustic impedance of the protective insulating layer, the acoustic impedance of the second electrode, and the acoustic impedance of the piezoelectric material layer of the ultrasonic sensor are matched.

[0182] In this embodiment, an organic insulating material having a certain thickness is coated as the protective insulating layer 22 of the device structure by a screen printing process.

[0183] Taking into account the installation position of the ultrasonic detection module, in an optional embodiment, the acoustic impedance of the protective insulating layer, the acoustic impedance of the second electrode, and the acoustic impedance of the piezoelectric material layer of the ultrasonic sensor are matched.

[0184] In this embodiment, considering that ultrasound waves are emitted and transmitted when propagating between two materials, and the ratio of ultrasound reflection to transmission is determined by the acoustic impedances of the two materials, when the acoustic impedances of the two materials differ greatly, ultrasound waves are reflected more and transmitted less when propagating between the two materials; conversely, when the acoustic impedances of the two materials differ less, ultrasound waves are reflected less and transmitted more when propagating between the two materials. Therefore, in this embodiment, when ultrasound waves need to be transmitted between the piezoelectric material layer, the second electrode, and the protective insulating layer, the difference between the acoustic impedances of the piezoelectric material layer, the second electrode, and the protective insulating layer is small, and the acoustic impedances of the three increase or decrease in sequence; whereas when ultrasound waves need to be reflected between the piezoelectric material layer, the second electrode, and the protective insulating layer, the difference between the acoustic impedances of the piezoelectric material layer, the second electrode, and the protective insulating layer is large, and the acoustic impedances of the three increase or decrease in sequence.

[0185] It should be noted that this embodiment does not specifically limit the acoustic impedance of the piezoelectric material layer, the acoustic impedance of the second electrode, and the acoustic impedance of the protective insulating layer. Those skilled in the art should select the piezoelectric material layer, the second electrode, and the protective insulating layer according to the installation requirements of the ultrasonic detection module and the direction of ultrasonic transmission, with the impedance matching among the three as the design criterion, which will not be repeated here.

[0186] In this embodiment, when the ultrasonic detection module is working, the specific characteristics are as follows:

[0187] In the transmitting stage, the detection circuit sets the first terminal of the ultrasonic sensor to a reset voltage in response to the reset control signal received by the reset unit, and the ultrasonic sensor transmits ultrasonic waves according to the input signal inputted at the second terminal thereof.

[0188] In the reading stage, the detection circuit responds to the reset control signal received by the reset unit and the transmission holding control signal received by the transmission holding unit, the ultrasonic sensor receives the reflected ultrasonic wave, the first end of the ultrasonic sensor outputs a first electrical signal, the first electrical signal is stored by the transmission holding unit and held in the storage unit according to a preset time, and the second electrical signal output by the storage unit is read in response to the read control signal received by the reading unit.

[0189] In another specific embodiment, Figure 5 The figure shows a circuit diagram of an ultrasonic detection module, wherein the reset unit T1, the transmission holding unit T2, the storage unit T3 and the reading unit T4 each include a first end, a second end and a control end;

[0190] The first end of the reset unit T1 and the first end of the transmission holding unit T2 are connected to the second node N2, the second end of the reset unit T1 is connected to the reset voltage Reset, the control end of the reset unit T1 is connected to the reset control signal, and the reset unit T1 sets the second node N2 to the reset voltage in response to the reset control signal;

[0191] The first end of the transmission holding unit T2 and the first end of the ultrasonic sensor PVDF are connected to the second node N2, the second end of the transmission holding unit T2 is connected to the first end of the storage unit T3, the control end of the transmission holding unit T2 is connected to the transmission holding control signal, and under the control of the reset control signal, the transmission holding unit T2 transmits the first electrical signal output from the first end of the ultrasonic sensor PVDF from the first end of the transmission holding unit T2 to the second end of the transmission holding unit T2 so as to be transmitted to the first end of the storage unit T3;

[0192] The second end of the storage unit T3 is connected to the first end of the reading unit T4, the control end of the storage unit T3 is connected to the storage control signal, and the storage unit T3 transmits the first electrical signal to the second end of the storage unit T3 in response to the storage control signal and outputs the first electrical signal as the second electrical signal;

[0193] The second end of the reading unit T4 is connected to the reading line, the control end of the reading unit T4 receives the reading control signal, and the reading unit T4 transmits the second electrical signal from the first end of the reading unit T4 to the second end of the reading unit T4 in response to the reading control signal.

[0194] like Figure 6 The following is a timing diagram of this embodiment. The working process of the ultrasonic detection module is as follows:

[0195] In the transmitting phase t0-t1, the detection circuit sets the first terminal of the ultrasonic sensor PVDF to the reset voltage Reset in response to the reset control signal received by the reset unit T1, and the ultrasonic sensor PVDF transmits ultrasonic waves according to the input signal inputted at its second terminal.

[0196] In this embodiment, in the transmission stage, the reset control signal and the transmission hold control signal are valid signals, the reset unit T1 and the transmission hold unit T2 are closed, the reset voltage Reset is at a low level, the second node N2 is the reset voltage, the control end of the storage unit T3 is the reset voltage, and the ultrasonic sensor PVDF transmits ultrasonic waves according to the received input signal.

[0197] In the reading phase t1-t4, the detection circuit responds to the reset control signal received by the reset unit and the transmission and holding control signal received by the transmission and holding unit, the ultrasonic sensor receives the reflected ultrasonic wave, the first end of the ultrasonic sensor outputs a first electrical signal, the first electrical signal is stored by the transmission and holding unit and is held in the storage unit for a preset time, and the second electrical signal output by the storage unit is read in response to the read control signal received by the reading unit.

[0198] In this embodiment, the reading phase is further divided into the following phases:

[0199] In the receiving sampling phase t1-t2, the reset control signal is an invalid signal, the reset unit T1 is disconnected, the transmission holding control signal is a valid signal, the transmission holding unit T2 is turned on, and the ultrasonic sensor PVDF receives the reflected ultrasonic wave and outputs a first electrical signal.

[0200] During the hold phase t2-t3, the ultrasonic sensor stops receiving the reflected ultrasonic wave and ceases to output the first electrical signal. The reset control signal and the transmission hold control signal are inactive, the reset unit T1 is disconnected, and the transmission hold unit T2 is disconnected. The control terminal of the storage unit T3 is closed in response to the storage control signal AP. Because the transmission hold unit T2 is a metal oxide thin film transistor with low leakage current, it maintains the first terminal of the storage unit T3, allowing the first electrical signal to be stored and held in the storage unit for a predetermined period of time.

[0201] During the readout phase t3-t4, the reset control signal and the transmission hold control signal are inactive, reset unit T1 is disconnected, and transmission hold unit T2 is disconnected. The control terminal of storage unit T3 is closed in response to storage control signal AP, closing storage unit T3. The readout control signal is active, closing readout unit T4, and reading the second electrical signal output by the storage unit to readout line Dn. It is worth noting that storage unit T3 operates in a follower state, following the first electrical signal and outputting the second electrical signal. Readout unit T4 then reads the second electrical signal.

[0202] like Figure 7 FIG. 1 is a schematic diagram of the structure of this embodiment. The ultrasonic detection module includes an ultrasonic sensor PVDF21 and a detection circuit. The detection circuit includes:

[0203] A patterned third active material layer is provided on the substrate 100 , wherein the third active material layer includes an active layer 270 of the reset unit T1 , the storage unit T3 , and the read unit T4 provided on the same layer;

[0204] a third gate insulating layer 130 covering the third active material layer and the exposed portion of the substrate 100 ;

[0205] A patterned third gate material layer is provided on the third gate insulating layer 130 , wherein the third gate material layer includes gates 260 Gate1 of the reset unit T1 , the storage unit T3 , and the read unit T4 provided on the same layer;

[0206] a third interlayer insulating layer 140 covering the third gate material layer and the exposed third gate insulating layer 130 ;

[0207] a patterned fourth active material layer disposed on the third interlayer insulating layer 140 , wherein the fourth active material layer is the active layer 250IGZO of the transmission holding unit T2 ;

[0208] a fourth gate insulating layer 160 covering the fourth active material layer and the exposed third interlayer insulating layer 140 ;

[0209] A patterned fourth gate material layer is provided on the fourth gate insulating layer 160 , wherein the fourth gate material layer is the gate 240 Gate2 of the transmission holding unit T2 ;

[0210] a fourth interlayer insulating layer 170 covering the fourth gate material layer and the exposed fourth gate insulating layer 160 ;

[0211] A patterned third metal layer is provided on the fourth interlayer insulating layer 170, wherein the third metal layer includes a source S and a drain D of the reset unit T1, a source S and a drain D of the transmission holding unit T2, a source S and a drain D of the storage unit T3, and a source S and a drain D of the reading unit T4, which are provided on the same layer, and the source S and the drain D are connected to the corresponding active layer through vias;

[0212] a third inorganic layer 180 covering the third metal layer and the exposed fourth interlayer insulating layer 170;

[0213] a patterned fourth metal layer SD2 disposed on the third inorganic layer 180 , the fourth metal layer being connected to the drain D of the transmission holding unit T2 and the source S of the storage unit T3 through corresponding vias; and

[0214] The fourth inorganic layer 190 covers the fourth metal layer SD2 and the exposed third inorganic layer 180 .

[0215] In this embodiment, a transmission holding unit formed by using a metal oxide thin film transistor is used to ensure that the first electrical signal is stored and maintained in the storage unit according to a preset time. That is, the small leakage current characteristic of the metal oxide thin film transistor is utilized to keep the first electrical signal stably stored in the storage unit, thereby improving the detection accuracy of the ultrasonic detection module, and especially improving the detection accuracy and stability of the ultrasonic detection module with a large area and high pixel density.

[0216] like Figure 7 As shown, the production process of the ultrasonic detection module is used to illustrate:

[0217] First, a detection circuit is formed on a substrate, specifically including:

[0218] In the first step, a patterned third active material layer is formed on the substrate 100 . The third active material layer includes the active layer of the reset unit T1 , the active layer of the storage unit T3 , and the active layer 270 of the read unit T4 , which are arranged on the same layer.

[0219] In this embodiment, a barrier layer 110 and a buffer layer 120 of a certain thickness are deposited on a substrate 100 by a plasma enhanced chemical vapor deposition (PECVD) device, and then an active material layer of a certain thickness is deposited on the buffer layer 120 by a PECVD device, and patterned by photolithography and etching processes to form an active layer 270 of the reset unit T1, the storage unit T3 and the read unit T4, and then the a-Si of the active layer is lightly doped by excimer laser crystallization (ELA) to change the crystal lattice to form polycrystalline silicon.

[0220] In a second step, a third gate insulating layer 130 is formed to cover the third active material layer and the exposed portion of the substrate 100 .

[0221] In this embodiment, silicon oxide SiO having a certain thickness is deposited as the third gate insulating layer 130 by using a PECVD device.

[0222] In the third step, a patterned third gate material layer is formed on the third gate insulating layer, wherein the third gate material layer includes the gate of the reset unit, the gate of the storage unit, and the gate of the read unit arranged in the same layer.

[0223] In this embodiment, a certain thickness of metal is deposited as the third gate material layer by sputtering equipment, and patterned by photolithography and etching processes to form the gates 260 of the reset unit T1 , the storage unit T3 , and the read unit T4 .

[0224] It is worth noting that, in this embodiment, the active layer is further heavily doped to reduce the contact resistance between the source and drain of the subsequent reset unit T1 , storage unit T3 and read unit T4 and the active layer, thereby improving the connection effect.

[0225] The fourth step is to form a third interlayer insulating layer covering the third gate material layer and the exposed third gate insulating layer.

[0226] In this embodiment, the first interlayer insulating layer 140 and the buffer layer 150 are deposited to a certain thickness using a PECVD device.

[0227] In a fifth step, a patterned fourth active material layer is formed on the third interlayer insulating layer, where the fourth active material layer is the active layer of the transmission maintaining unit.

[0228] In this embodiment, a fourth active material layer IGZO is deposited to a certain thickness by using a Sputter device, and is patterned by photolithography and etching processes to form the active layer 250 of the transmission maintaining unit T2 .

[0229] In the sixth step, a fourth gate insulating layer is formed to cover the fourth active material layer and the exposed third interlayer insulating layer.

[0230] In this embodiment, SiO with a certain thickness is deposited as the fourth gate insulating layer 160 by using a PECVD device.

[0231] In the seventh step, a patterned fourth gate material layer is formed on the fourth gate insulating layer, and the fourth gate material layer serves as the gate of the transmission holding unit.

[0232] In this embodiment, a metal having a certain thickness is deposited as the fourth gate material layer by a Sputter device, and patterned by photolithography and etching processes to form the gate 240 of the transmission holding unit T2.

[0233] In the eighth step, a fourth interlayer insulating layer is formed to cover the fourth gate material layer and the exposed fourth gate insulating layer.

[0234] In this embodiment, the fourth interlayer insulating layer 170 is deposited to a certain thickness by using a PECVD device.

[0235] The ninth step is to form a patterned third metal layer on the fourth interlayer insulating layer, wherein the third metal layer includes the source and drain of the reset unit, the source and drain of the transmission holding unit, the source and drain of the storage unit, and the source and drain of the reading unit arranged on the same layer, and the source and drain are connected to the corresponding active layer through vias.

[0236] In this embodiment, a first metal layer of Ti / Al / Ti metal of a certain thickness is deposited by a Sputter device, and patterned by photolithography and etching processes to form the source S and drain D of the reset unit T1, the source S and drain D of the transmission holding unit T2, the source S and drain D of the storage unit T3, and the source S and drain D of the reading unit T4.

[0237] In the tenth step, a third inorganic layer is formed to cover the fourth metal layer and the exposed fourth interlayer insulating layer.

[0238] In this embodiment, the third inorganic layer 180 is deposited to a certain thickness by using a PECVD device.

[0239] In the eleventh step, a patterned fourth metal layer is formed on the third inorganic layer, wherein the fourth metal layer is respectively connected to the drain of the transmission holding unit and the source of the storage unit through corresponding via holes.

[0240] In this embodiment, a certain thickness of ITO metal is deposited by a Sputter device and patterned by photolithography and etching processes to form a fourth metal layer SD2. The fourth metal layer SD2 is connected to the drain D of the transmission holding unit T2 and the source S of the storage unit T3 through corresponding vias.

[0241] In an optional embodiment, the fourth metal layer is reused as the first electrode of the ultrasonic sensor.

[0242] In this embodiment, the fourth metal layer of the detection circuit is reused as the first electrode of the ultrasonic sensor, which effectively reduces the thickness of the ultrasonic detection module.

[0243] In the twelfth step, a fourth inorganic layer is formed to cover the fourth metal layer and expose the third inorganic layer.

[0244] In this embodiment, silicon nitride SiN is deposited to a certain thickness as the fourth inorganic layer 190 by using a PECVD device.

[0245] In the thirteenth step, a piezoelectric material layer is formed covering the fourth inorganic layer.

[0246] In this embodiment, a PVDF solution is applied to a certain thickness using a spin coating device, crystallized, and solidified. A Mo / AlNd / Mo metal layer is then deposited at a certain thickness at low temperature as a hard mask to pattern the PVDF using a dry etching process. Finally, a polarization process is performed to impart piezoelectric properties to the PVDF, thereby forming a piezoelectric material layer 200.

[0247] Step 14: forming a second electrode covering the piezoelectric material layer.

[0248] In this embodiment, a silver paste having a certain thickness is coated by a screen printing process as the second electrode 210 of the sandwich piezoelectric sensor device structure.

[0249] In the fifteenth step, a protective insulating layer is formed to cover the ultrasonic sensor, and the acoustic impedance of the protective insulating layer, the acoustic impedance of the second electrode, and the acoustic impedance of the piezoelectric material layer of the ultrasonic sensor are matched.

[0250] In this embodiment, an organic insulating material having a certain thickness is coated by a screen printing process as the protective insulating layer 220 of the device structure.

[0251] Taking into account the installation position of the ultrasonic detection module, in an optional embodiment, the acoustic impedance of the protective insulating layer, the acoustic impedance of the second electrode, and the acoustic impedance of the piezoelectric material layer of the ultrasonic sensor are matched.

[0252] In this embodiment, considering that ultrasound waves are emitted and transmitted when propagating between two materials, and the ratio of ultrasound reflection to transmission is determined by the acoustic impedances of the two materials, when the acoustic impedances of the two materials differ greatly, ultrasound waves are reflected more and transmitted less when propagating between the two materials; conversely, when the acoustic impedances of the two materials differ less, ultrasound waves are reflected less and transmitted more when propagating between the two materials. Therefore, in this embodiment, when ultrasound waves need to be transmitted between the piezoelectric material layer, the second electrode, and the protective insulating layer, the difference between the acoustic impedances of the piezoelectric material layer, the second electrode, and the protective insulating layer is small, and the acoustic impedances of the three increase or decrease in sequence; whereas when ultrasound waves need to be reflected between the piezoelectric material layer, the second electrode, and the protective insulating layer, the difference between the acoustic impedances of the piezoelectric material layer, the second electrode, and the protective insulating layer is large, and the acoustic impedances of the three increase or decrease in sequence.

[0253] It should be noted that this embodiment does not specifically limit the acoustic impedance of the piezoelectric material layer, the acoustic impedance of the second electrode, and the acoustic impedance of the protective insulating layer. Those skilled in the art should select the piezoelectric material layer, the second electrode, and the protective insulating layer according to the installation requirements of the ultrasonic detection module and the direction of ultrasonic transmission, with the impedance matching among the three as the design criterion, which will not be repeated here.

[0254] In this embodiment, when the ultrasonic detection module is working, the specific characteristics are as follows:

[0255] In the transmitting stage, the detection circuit sets the first terminal of the ultrasonic sensor to a reset voltage in response to the reset control signal received by the reset unit, and the ultrasonic sensor transmits ultrasonic waves according to the input signal inputted at the second terminal thereof.

[0256] In the reading stage, the detection circuit responds to the reset control signal received by the reset unit and the transmission holding control signal received by the transmission holding unit, the ultrasonic sensor receives the reflected ultrasonic wave, the first end of the ultrasonic sensor outputs a first electrical signal, the first electrical signal is stored by the transmission holding unit and held in the storage unit according to a preset time, and the second electrical signal output by the storage unit is read in response to the read control signal received by the reading unit.

[0257] Taking into account the resonant frequency used by the ultrasonic detection module, in an optional embodiment, the thickness of the piezoelectric material layer of the ultrasonic sensor is:

[0258]

[0259] Wherein, f0 is the resonant frequency of the ultrasonic wave, n is the frequency order, E is the Young's modulus of the piezoelectric material layer, and ρ is the density of the piezoelectric material layer.

[0260] In this embodiment, according to the relationship between the thickness of the piezoelectric material layer of the ultrasonic sensor and the resonant frequency, different resonant frequencies can be obtained by adjusting the thickness of the piezoelectric material layer of the ultrasonic sensor; and by adjusting the thickness of the piezoelectric material layer of the ultrasonic sensor, the actual application direction can be adjusted, for example, according to the working frequency of the ultrasound, it can be applied to the consumer electronics field, the automotive field, the industrial field, and the medical detection field.

[0261] Corresponding to the ultrasonic detection module provided in the above embodiment, one embodiment of the present application further provides a method for manufacturing the above ultrasonic detection module, comprising:

[0262] A detection circuit is formed on a substrate, the detection circuit comprising a reset unit, a transmission and holding unit, a storage unit, and a reading unit, wherein the detection circuit receives a first electrical signal output by an ultrasonic sensor in response to a reset control signal received by the reset unit and a transmission and holding control signal received by the transmission and holding unit, stores the first electrical signal through the transmission and holding unit and holds it in the storage unit for a preset time, and reads a second electrical signal output by the transmission and holding unit in response to a read control signal received by the reading unit, the reset unit, the storage unit, and the reading unit being low-temperature polysilicon thin-film transistors, and the transmission and holding unit being a metal oxide thin-film transistor;

[0263] An ultrasonic sensor for transmitting ultrasonic waves, receiving returned ultrasonic waves, and outputting the first electrical signal is formed on the detection circuit.

[0264] Since the manufacturing method provided in the embodiment of the present application corresponds to the ultrasonic detection module provided in the above-mentioned embodiments, the previous implementation method is also applicable to the manufacturing method provided in this embodiment and will not be described in detail in this embodiment.

[0265] Corresponding to the ultrasonic detection module provided in the above embodiment, one embodiment of the present application further provides a driving method using the above ultrasonic detection module, including:

[0266] In the transmitting stage, in response to the reset control signal received by the reset unit, the first terminal of the ultrasonic sensor is set to a reset voltage, and the ultrasonic sensor transmits ultrasonic waves according to the input signal inputted at the second terminal thereof;

[0267] In the reading stage, in response to the reset control signal received by the reset unit and the transmission and holding control signal received by the transmission and holding unit, the ultrasonic sensor receives the reflected ultrasonic wave, the first end of the ultrasonic sensor outputs a first electrical signal, the first electrical signal is stored by the transmission and holding unit and is held in the storage unit for a preset time, and the second electrical signal output by the storage unit is read in response to the read control signal received by the reading unit.

[0268] Since the driving method provided in the embodiment of the present application corresponds to the ultrasonic detection module provided in the above-mentioned embodiments, the previous implementation is also applicable to the driving method provided in this embodiment and will not be described in detail in this embodiment.

[0269] An embodiment of the present application further provides an under-screen ultrasonic imaging display device, comprising a display panel and the above-mentioned ultrasonic detection module, wherein

[0270] The display panel includes a substrate and a display substrate arranged on the substrate;

[0271] The side of the substrate of the ultrasonic detection module away from the ultrasonic sensor and the side of the substrate of the display panel away from the display substrate are attached by adhesive.

[0272] In this embodiment, the ultrasonic detection module is inverted on the side opposite to the light-emitting side of the display panel to realize an under-screen ultrasonic imaging display device in which the ultrasonic detection module is integrated into the display panel. For example, the ultrasonic detection module is set under the screen of a mobile terminal to realize under-screen fingerprint detection.

[0273] Specifically, such as Figure 8a The figure shows a schematic diagram of the structure of an under-screen ultrasonic imaging display device. During the transmission phase, the detection circuit of the ultrasonic detection module responds to a reset control signal received by a reset unit, setting the first terminal of the ultrasonic sensor to a reset voltage. The ultrasonic sensor then transmits ultrasonic waves based on an input signal inputted to its second terminal. During the reading phase, the detection circuit of the ultrasonic detection module responds to the reset control signal received by the reset unit and the transmission and hold control signal received by the transmission and hold unit. The ultrasonic sensor receives reflected ultrasonic waves, and the first terminal of the ultrasonic sensor outputs a first electrical signal. The transmission and hold unit stores the first electrical signal and holds it in a storage unit for a preset time. The storage unit amplifies the first electrical signal and outputs a second electrical signal. The reading unit reads the second electrical signal in response to the received read control signal and outputs it to a read line.

[0274] Specifically, such as Figure 8bThe figure shows a schematic diagram of the structure of another under-screen ultrasonic imaging display device. During the transmission phase, the detection circuit of the ultrasonic detection module responds to the reset control signal received by the reset unit to set the first terminal of the ultrasonic sensor to a reset voltage. The ultrasonic sensor then transmits ultrasonic waves based on the input signal input to its second terminal. During the reading phase, the detection circuit of the ultrasonic detection module responds to the reset control signal received by the reset unit and the transmission and hold control signal received by the transmission and hold unit. The ultrasonic sensor receives reflected ultrasonic waves, and the first terminal of the ultrasonic sensor outputs a first electrical signal. The transmission and hold unit stores the first electrical signal and holds it in the storage unit for a preset time. The storage unit then follows the first electrical signal and outputs a second electrical signal. The reading unit reads the second electrical signal in response to the received read control signal and outputs it to the read line.

[0275] It is worth noting that in the under-screen ultrasonic imaging display device of this embodiment, the ultrasonic detection module is inverted under the display panel. According to the transmission direction of the ultrasonic wave, when the ultrasonic wave reflected by the object to be imaged is received, the ultrasonic wave needs to be reflected between the piezoelectric material layer and the second electrode, and the second electrode and the protective insulating layer of the ultrasonic sensor when it is transmitted. The ultrasonic wave is then reflected to the piezoelectric layer to improve the sensing accuracy of the ultrasonic sensor. Therefore, the acoustic impedance of the piezoelectric material layer of the ultrasonic sensor, the acoustic impedance of the second electrode, and the acoustic impedance of the protective insulating layer are quite different, resulting in greater reflection and less transmission of the ultrasonic wave, and the acoustic impedances of the three are in increasing order.

[0276] This embodiment forms an under-screen ultrasonic imaging display device by inverting the ultrasonic detection module on the side of the display panel away from the light-emitting side. The ultrasonic detection module uses a detection circuit to detect the first electrical signal output by the ultrasonic sensor, and ensures that the first electrical signal is stored and maintained in the storage unit according to a preset time by using a transmission holding unit formed by a metal oxide thin-film transistor. That is, the small leakage current characteristic of the metal oxide thin-film transistor is used to keep the first electrical signal stably stored in the storage unit, thereby improving the detection accuracy of the under-screen ultrasonic imaging display device, especially improving the detection accuracy and stability of large-area, high-pixel-density under-screen ultrasonic imaging display devices, thereby compensating for the problems existing in the existing technology and having broad application prospects.

[0277] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. An ultrasonic detection module, characterized in that: It includes a detection circuit and an ultrasonic sensor stacked on a substrate, wherein: The ultrasonic sensor is configured to transmit ultrasonic waves, receive reflected ultrasonic waves, and output a first electrical signal; The detection circuit includes a reset unit, a transmission holding unit, a storage unit, and a reading unit, wherein the detection circuit receives the first electrical signal in response to a reset control signal received by the reset unit and a transmission holding control signal received by the transmission holding unit, stores the first electrical signal through the transmission holding unit and holds it in the storage unit for a preset time, and reads the second electrical signal output by the transmission holding unit in response to a read control signal received by the reading unit; The reset unit, storage unit and reading unit are low-temperature polysilicon thin film transistors, and the transmission holding unit is a metal oxide thin film transistor; The detection circuit comprises: A patterned first active material layer is provided on the substrate, wherein the first active material layer includes an active layer of the reset unit, an active layer of the storage unit, and an active layer of the read unit provided on the same layer; a first gate insulating layer covering the first active material layer and the exposed portion of the substrate; a patterned first gate material layer disposed on the first gate insulating layer, wherein the first gate material layer includes a gate of the reset unit, a gate of the storage unit, and a gate of the read unit disposed on the same layer; a first interlayer insulating layer covering the first gate material layer and the exposed first gate insulating layer; a patterned second active material layer disposed on the first interlayer insulating layer, wherein the second active material layer is an active layer of the transmission maintaining unit; a second gate insulating layer covering the second active material layer and the exposed first interlayer insulating layer; a patterned second gate material layer disposed on the second gate insulating layer, wherein the second gate material layer serves as a gate of the transmission holding unit; a second interlayer insulating layer covering the second gate material layer and the exposed second gate insulating layer; a patterned first metal layer disposed on the second interlayer insulating layer, the first metal layer including a source and a drain of the reset unit, a source and a drain of the transmission holding unit, a source and a drain of the storage unit, and a source and a drain of the reading unit, and a first connection metal disposed on the same layer, the source and the drain being connected to the corresponding active layer through vias, and the first connection metal being connected to the gate of the storage unit through the via; a first inorganic layer covering the first metal layer and the exposed second interlayer insulating layer; a patterned second metal layer disposed on the first inorganic layer, the second metal layer being connected to the drain electrode of the transmission holding unit and the first connection metal through corresponding vias; and A second inorganic layer covers the second metal layer and the exposed first inorganic layer.

2. The ultrasonic detection module according to claim 1, characterized in that: The reset unit, the transmission holding unit, the storage unit and the reading unit each include a first end, a second end and a control end; The first end of the reset unit and the first end of the transmission holding unit are connected to a first node, the second end of the reset unit is connected to a reset voltage, the control end of the reset unit is connected to the reset control signal, and the reset unit sets the first node to the reset voltage in response to the reset control signal; The first end of the transmission holding unit and the first end of the ultrasonic sensor are connected to the first node, the second end of the transmission holding unit is connected to the control end of the storage unit, the control end of the transmission holding unit is connected to the transmission holding control signal, and under the control of the reset control signal, the transmission holding unit transmits the first electrical signal output by the first end of the ultrasonic sensor from the first end of the transmission holding unit to the second end of the transmission holding unit to transmit it to the control end of the storage unit in response to the transmission holding control signal; The first end of the storage unit is connected to the first power signal, the second end of the storage unit is connected to the first end of the reading unit, and the storage unit amplifies the first electrical signal and outputs the second electrical signal; The second end of the reading unit is connected to the reading line, the control end of the reading unit receives the reading control signal, and the reading unit transmits the second electrical signal from the first end of the reading unit to the second end of the reading unit in response to the reading control signal.

3. The ultrasonic detection module according to claim 1, characterized in that: The ultrasonic sensor comprises: a first electrode reused by the second metal layer; a piezoelectric material layer covering the second inorganic layer; and A second electrode covers the piezoelectric material layer.

4. The ultrasonic detection module according to claim 1, characterized in that: The reset unit, the transmission holding unit, the storage unit and the reading unit each include a first end, a second end and a control end; The first end of the reset unit and the first end of the transmission holding unit are connected to a second node, the second end of the reset unit is connected to a reset voltage, the control end of the reset unit is connected to the reset control signal, and the reset unit sets the second node to the reset voltage in response to the reset control signal; The first end of the transmission holding unit and the first end of the ultrasonic sensor are connected to the second node, the second end of the transmission holding unit is connected to the first end of the storage unit, the control end of the transmission holding unit is connected to the transmission holding control signal, and under the control of the reset control signal, the transmission holding unit transmits the first electrical signal output by the first end of the ultrasonic sensor from the first end of the transmission holding unit to the second end of the transmission holding unit to transmit it to the first end of the storage unit in response to the transmission holding control signal; The second end of the storage unit is connected to the first end of the reading unit, the control end of the storage unit is connected to the storage control signal, and the storage unit transmits the first electrical signal to the second end of the storage unit in response to the storage control signal and outputs the first electrical signal as the second electrical signal; The second end of the reading unit is connected to the reading line, the control end of the reading unit receives the reading control signal, and the reading unit transmits the second electrical signal from the first end of the reading unit to the second end of the reading unit in response to the reading control signal.

5. The ultrasonic detection module according to claim 4, characterized in that: The detection circuit comprises: a patterned third active material layer disposed on the substrate, the third active material layer comprising an active layer of the reset unit, an active layer of the storage unit, and an active layer of the read unit disposed on the same layer; a third gate insulating layer covering the third active material layer and the exposed portion of the substrate; a patterned third gate material layer disposed on the third gate insulating layer, wherein the third gate material layer includes a gate of the reset unit, a gate of the storage unit, and a gate of the read unit disposed on the same layer; a third interlayer insulating layer covering the third gate material layer and the exposed third gate insulating layer; a patterned fourth active material layer disposed on the third interlayer insulating layer, wherein the fourth active material layer is an active layer of the transmission maintaining unit; a fourth gate insulating layer covering the fourth active material layer and the exposed third interlayer insulating layer; a patterned fourth gate material layer disposed on the fourth gate insulating layer, wherein the fourth gate material layer serves as a gate of the transmission holding unit; a fourth interlayer insulating layer covering the fourth gate material layer and the exposed fourth gate insulating layer; A patterned third metal layer is provided on the fourth interlayer insulating layer, the third metal layer including a source and a drain of the reset unit, a source and a drain of the transmission holding unit, a source and a drain of the storage unit, and a source and a drain of the reading unit provided on the same layer, the source and the drain being connected to the corresponding active layer through vias; a third inorganic layer covering the third metal layer and the exposed fourth interlayer insulating layer; a patterned fourth metal layer disposed on the third inorganic layer, the fourth metal layer being connected to the drain of the transmission holding unit and the source of the storage unit through corresponding vias; and A fourth inorganic layer covers the fourth metal layer and the exposed third inorganic layer.

6. The ultrasonic detection module according to claim 5, characterized in that: The ultrasonic sensor comprises: a first electrode reused by the fourth metal layer; a piezoelectric material layer covering the fourth inorganic layer; and A second electrode covers the piezoelectric material layer.

7. The ultrasonic detection module according to claim 3 or 6, characterized in that: The ultrasonic sensor further includes a protective insulating layer covering the ultrasonic sensor, wherein the acoustic impedance of the protective insulating layer, the acoustic impedance of the second electrode, and the acoustic impedance of the piezoelectric material layer of the ultrasonic sensor are matched.

8. The ultrasonic detection module according to claim 3 or 6, characterized in that: The thickness of the piezoelectric material layer of the ultrasonic sensor is: ； in, is the resonant frequency of the ultrasonic wave, n is the frequency order, E is the Young's modulus of the piezoelectric material layer, is the density of the piezoelectric material layer.

9. A method for manufacturing an ultrasonic detection module according to any one of claims 1 to 8, characterized in that: include: A detection circuit is formed on a substrate, the detection circuit comprising a reset unit, a transmission and holding unit, a storage unit, and a reading unit, wherein the detection circuit receives a first electrical signal output by an ultrasonic sensor in response to a reset control signal received by the reset unit and a transmission and holding control signal received by the transmission and holding unit, stores the first electrical signal through the transmission and holding unit and holds it in the storage unit for a preset time, and reads a second electrical signal output by the transmission and holding unit in response to a read control signal received by the reading unit, the reset unit, the storage unit, and the reading unit being low-temperature polysilicon thin-film transistors, and the transmission and holding unit being a metal oxide thin-film transistor; An ultrasonic sensor is formed on the detection circuit for transmitting ultrasonic waves, receiving returned ultrasonic waves, and outputting the first electrical signal; The forming of the detection circuit on the substrate further comprises: forming a patterned first active material layer on the substrate, wherein the first active material layer includes an active layer of the reset unit, an active layer of the storage unit, and an active layer of the read unit arranged on the same layer; forming a first gate insulating layer covering the first active material layer and the exposed portion of the substrate; forming a patterned first gate material layer on the first gate insulating layer, wherein the first gate material layer includes a gate of the reset unit, a gate of the storage unit, and a gate of the read unit arranged in the same layer; forming a first interlayer insulating layer covering the first gate material layer and the exposed first gate insulating layer; forming a patterned second active material layer on the first interlayer insulating layer, wherein the second active material layer is an active layer of the transmission maintaining unit; forming a second gate insulating layer covering the second active material layer and the exposed first interlayer insulating layer; forming a patterned second gate material layer on the second gate insulating layer, wherein the second gate material layer serves as a gate of the transmission holding unit; forming a second interlayer insulating layer covering the second gate material layer and the exposed second gate insulating layer; forming a patterned first metal layer on the second interlayer insulating layer, the first metal layer including a source and a drain of the reset unit, a source and a drain of the transmission holding unit, a source and a drain of the storage unit, and a source and a drain of the reading unit, and a first connection metal, the source and the drain being connected to the corresponding active layer through vias, and the first connection metal being connected to the gate of the storage unit through the via; forming a first inorganic layer covering the first metal layer and the exposed second interlayer insulating layer; forming a patterned second metal layer on the first inorganic layer, wherein the second metal layer is respectively connected to the drain electrode of the transmission holding unit and the first connection metal through corresponding via holes; and A second inorganic layer is formed to cover the second metal layer and the exposed first inorganic layer.

10. The manufacturing method according to claim 9, characterized in that: The ultrasonic sensor formed on the detection circuit for transmitting ultrasonic waves, receiving returned ultrasonic waves and outputting the first electrical signal further includes: reusing the second metal layer as a first electrode; forming a piezoelectric material layer covering the second inorganic layer; and A second electrode is formed covering the piezoelectric material layer.

11. The manufacturing method according to claim 9, characterized in that: The forming of the detection circuit on the substrate further comprises: forming a patterned third active material layer on the substrate, wherein the third active material layer includes an active layer of the reset unit, an active layer of the storage unit, and an active layer of the read unit arranged on the same layer; forming a third gate insulating layer covering the third active material layer and the exposed portion of the substrate; forming a patterned third gate material layer on the third gate insulating layer, wherein the third gate material layer includes a gate of the reset unit, a gate of the storage unit, and a gate of the read unit arranged on the same layer; forming a third interlayer insulating layer covering the third gate material layer and the exposed third gate insulating layer; forming a patterned fourth active material layer on the third interlayer insulating layer, wherein the fourth active material layer is an active layer of the transmission maintaining unit; forming a fourth gate insulating layer covering the fourth active material layer and the exposed third interlayer insulating layer; forming a patterned fourth gate material layer on the fourth gate insulating layer, wherein the fourth gate material layer serves as the gate of the transmission holding unit; forming a fourth interlayer insulating layer covering the fourth gate material layer and the exposed fourth gate insulating layer; forming a patterned third metal layer on the fourth interlayer insulating layer, the third metal layer including a source and a drain of the reset unit, a source and a drain of the transmission holding unit, a source and a drain of the storage unit, and a source and a drain of the reading unit, the source and the drain being connected to the corresponding active layer through vias; forming a third inorganic layer covering the third metal layer and the exposed fourth interlayer insulating layer; forming a patterned fourth metal layer on the third inorganic layer, wherein the fourth metal layer is respectively connected to the drain of the transmission holding unit and the source of the storage unit through corresponding via holes; and forming a fourth inorganic layer covering the fourth metal layer and exposing the third inorganic layer The ultrasonic sensor formed on the detection circuit for transmitting ultrasonic waves, receiving returned ultrasonic waves and outputting the first electrical signal further includes: Reusing the fourth metal layer as a first electrode; forming a piezoelectric material layer covering the fourth inorganic layer; and A second electrode is formed covering the piezoelectric material layer.

12. The manufacturing method according to claim 9, characterized in that: After forming an ultrasonic sensor on the detection circuit for emitting ultrasonic waves, receiving returned ultrasonic waves and outputting the first electrical signal, it also includes: forming a protective insulating layer covering the ultrasonic sensor, and matching the acoustic impedance of the protective insulating layer, the acoustic impedance of the second electrode, and the acoustic impedance of the piezoelectric material layer of the ultrasonic sensor.

13. A driving method using the ultrasonic detection module according to any one of claims 1 to 8, characterized in that: include: In the transmitting stage, in response to the reset control signal received by the reset unit, the first terminal of the ultrasonic sensor is set to a reset voltage, and the ultrasonic sensor transmits ultrasonic waves according to the input signal inputted at the second terminal thereof; In the reading stage, in response to the reset control signal received by the reset unit and the transmission holding control signal received by the transmission holding unit, the ultrasonic sensor receives the reflected ultrasonic wave, the first end of the ultrasonic sensor outputs a first electrical signal, the first electrical signal is stored by the transmission holding unit and held in the storage unit according to a preset time, and the second electrical signal output by the storage unit is read in response to the read control signal received by the reading unit.

14. An under-screen ultrasound imaging display device, characterized in that: comprising a display panel and an ultrasonic detection module as claimed in any one of claims 1 to 8, wherein The display panel includes a substrate and a display substrate arranged on the substrate; The side of the substrate of the ultrasonic detection module away from the ultrasonic sensor and the side of the substrate of the display panel away from the display substrate are attached by adhesive.

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