Detection panel, detection device and detection method

Abstract

The invention provides a detection panel, a detection device and a detection method, and relates to the technical field of ultrasound, the detection panel comprises multiple layers of matrix devices, and every two adjacent layers of matrix devices are in coupled connection through a coupling layer; the matrix device comprises a plurality of array elements, the plurality of array elements are arranged in an array, each array element comprises a pixel circuit and a piezoelectric unit, and the pixel circuit is electrically connected with the piezoelectric unit; the multi-layer matrix device comprises a layer of reference device and at least one layer of equivalent device, and array elements of the reference device and array elements at the same position in the equivalent device are arranged in an aligned manner along a first direction; wherein the first direction is perpendicular to the surface, receiving ultrasonic signals, of the multi-layer matrix device. The overall sampling time can be shortened, the sampling efficiency of ultrasonic signals is improved, and the detection effect of the detection panel is improved.

Description

Technical Field

[0001] This application relates to the field of ultrasonic technology, and particularly to a detection panel, a detection device, and a detection method. Background Art

[0002] In the field of ultrasonic detection such as wearable ultrasound and ultrasonic imaging, an ultrasonic time-domain signal can be collected by a detection device composed of a matrix piezoelectric pixel device. For a period of ultrasonic signal, it is usually necessary to sample the signal waveform at multiple different times to obtain the sampled signal corresponding to the ultrasonic signal.

[0003] Currently, the detection device usually includes a single matrix piezoelectric pixel device. At each sampling moment, this matrix piezoelectric pixel device takes a certain amount of time to complete the sampling process. Therefore, it takes a long time to complete the sampling work at all sampling moments, and there are problems of long sampling time and low efficiency. Summary of the Invention

[0004] This application provides a detection panel, a detection device, and a detection method, which can solve the problems of long sampling time and low efficiency of the current detection device.

[0005] In a first aspect, this application provides a detection panel. The detection panel includes multiple layers of matrix devices, and adjacent two layers of the matrix devices are coupled and connected through a coupling layer;

[0006] The matrix device includes a plurality of array elements, the plurality of array elements are arranged in an array, the array element includes a pixel circuit and a piezoelectric unit, and the pixel circuit and the piezoelectric unit are electrically connected;

[0007] The multiple layers of matrix devices include one layer of reference device and at least one layer of equivalent device. The array elements of the reference device and the array elements at the same position in the equivalent device are arranged in alignment along a first direction; wherein, the first direction is perpendicular to the surface of the multiple layers of matrix devices for receiving ultrasonic signals.

[0008] Optionally, the alignment deviation between the array elements of the reference device and the array elements arranged in alignment in the equivalent device is less than a first wavelength; wherein, the first wavelength is equal to half of the wavelength of the ultrasonic signal.

[0009] Optionally, the distance between the same film layers of the reference device and the equivalent device along the first direction is not greater than the wavelength of the ultrasonic signal.

[0010] Optionally, the detection panel satisfies the following formula:

[0011] N×d 1 +(N - 1)×d 2 =(i + 1 / 4)×λ

[0012] where N represents the number of layers of the multi-layer matrix device, and d 1 represents the thickness of the matrix device, d 2 represents the thickness of the coupling layer, λ represents the wavelength of the ultrasonic signal, and i is a non-negative integer.

[0013] Optionally, the acoustic impedance of the coupling layer is substantially equal to the acoustic impedance of the matrix device.

[0014] Optionally, the matrix device further includes a control signal line; the pixel circuit in the array element includes a control transistor and a storage capacitor, and the piezoelectric unit includes a first electrode and a piezoelectric layer arranged in a stacked manner, and the first electrode is located on the side of the piezoelectric unit close to the pixel circuit;

[0015] The control electrode of the control transistor is electrically connected to the control signal line, the first pole of the control transistor is electrically connected to the storage capacitor, and the second pole of the control transistor is electrically connected to the first electrode; wherein, the control signal lines to which the control transistors in different layers of the matrix device are electrically connected are independent of each other.

[0016] In a second aspect, an embodiment of the present application provides a detection device, which includes the detection panel as described in the first aspect, and a control circuit, and the control circuit is electrically connected to the detection panel.

[0017] In a third aspect, an embodiment of the present application provides a detection method for controlling the detection panel as described in the first aspect, and the detection method includes:

[0018] Controlling the reference device to sample the ultrasonic signal received by the detection panel at the reference moment in each sampling group, and controlling the equivalent device to sample the ultrasonic signal at the target moment corresponding to each sampling group;

[0019] wherein, the preset M sampling moments are divided into multiple sampling groups, each sampling group includes N sampling moments, and N is equal to the number of layers of the multi-layer matrix device; the time sequence of the reference moment and the target moment in the sampling group corresponds one-to-one to the reception sequence of the ultrasonic signal by the reference device and the equivalent device in the multi-layer matrix device.

[0020] Optionally, controlling the equivalent device to sample the ultrasonic signal at the target moment corresponding to each sampling group includes:

[0021] Controlling the equivalent device to sample the ultrasonic signal at the equivalent moment corresponding to each sampling group; wherein, the equivalent moment is equal to the sum of the target moment and the target time difference; the absolute value of the target time difference is the ratio of the distance between the equivalent device and the reference device along the first direction to the sound speed;

[0022] Among them, the target time difference corresponding to the equivalent device that receives the ultrasonic signal earlier than the reference device is negative, and the target time difference corresponding to the equivalent device that receives the ultrasonic signal later than the reference device is positive.

[0023] Optionally, sampling the ultrasonic signal received by the detection panel at the reference moment of each sampling group for the control reference device includes:

[0024] At the reference moment of each sampling group, sending a control signal with a first level to the control signal line corresponding to the reference device, so that the control transistor of the pixel circuit in the element of the reference device disconnects the storage capacitor of the pixel circuit from the first electrode of the piezoelectric unit, and stores the sampling signal corresponding to the element in the storage capacitor;

[0025] Sampling the ultrasonic signal at the target moment corresponding to the equivalent device in the sampling group includes:

[0026] At the target moment corresponding to each sampling group, sending the control signal with the first level to the control signal line corresponding to the equivalent device, so that the control transistor of the pixel circuit in the element of the equivalent device disconnects the storage capacitor of the pixel circuit from the first electrode of the piezoelectric unit, and stores the sampling signal corresponding to the element in the storage capacitor.

[0027] A detection panel, a detection device and a detection method provided by the present application have at least the following advantages: The detection panel includes multiple layers of matrix devices, and adjacent layers of matrix devices are coupled and connected through a coupling layer, so that the multiple layers of matrix devices form an integral body. The matrix device includes a plurality of elements, the plurality of elements are arranged in an array, the element includes a pixel circuit and a piezoelectric unit, and the pixel circuit and the piezoelectric unit are electrically connected. The ultrasonic beam can be sampled through the element array of the matrix device, and the acoustic-electric conversion is completed by the pixel circuit and the piezoelectric unit in the element. The multiple layers of matrix devices include one layer of reference device and at least one layer of equivalent device. The elements of the reference device and the elements at the same position in the equivalent device are arranged in alignment along a first direction, and the first direction is perpendicular to the surface of the multiple layers of matrix devices for receiving ultrasonic signals. In this way, the element array in the reference device and the element array in the equivalent device can be roughly aligned along the first direction. By sampling the ultrasonic signal through the multiple layers of matrix devices, compared with the sampling of the ultrasonic signal by a single device in the related art, in this embodiment, the reference device and the equivalent device can sample at different sampling moments, and the multiple layers of matrix devices complete the sampling work at all sampling moments, which can shorten the overall sampling time. Therefore, the sampling efficiency of the ultrasonic signal can be improved, and the detection effect of the detection panel can be improved. Description of the Drawings

[0028] To more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for the description of the embodiments of the present application or related technologies. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Figure 1 It is one of the schematic structural diagrams of a detection panel provided by an embodiment of the present application;

[0030] Figure 2 It is the schematic matrix structure diagram of a matrix device provided by an embodiment of the present application;

[0031] Figure 3 It is the schematic film layer structure diagram of a matrix device provided by an embodiment of the present application;

[0032] Figure 4 It is the second schematic structural diagram of a detection panel provided by an embodiment of the present application;

[0033] Figure 5 It is the schematic diagram of the detection of ultrasonic signals by a detection panel provided by an embodiment of the present application;

[0034] Figure 6 It is the schematic film layer structure diagram of a detection panel provided by an embodiment of the present application;

[0035] Figure 7 It is the schematic circuit structure diagram of an array element provided by an embodiment of the present application;

[0036] Figure 8 It is the schematic diagram of an ultrasonic signal provided by an embodiment of the present application;

[0037] Figure 9 It is the schematic diagram of a sampling signal provided by an embodiment of the present application;

[0038] Figure 10 It is the schematic diagram of the steps of a detection method provided by an embodiment of the present application;

[0039] Figure 11 It is the schematic diagram of the sampling process of ultrasonic signals by a piezoelectric pixel device in the related art;

[0040] Figure 12 It is the schematic diagram of the sampling process of ultrasonic signals by a detection panel provided by an embodiment of the present application;

[0041] Figure 13 It is the schematic diagram of the sampling result of a detection method provided by an embodiment of the present application;

[0042] Figure 14It is a schematic diagram of the propagation of an ultrasonic beam provided by an embodiment of the present application;

[0043] Figure 15 It is one of the timing schematic diagrams of a detection method provided by an embodiment of the present application;

[0044] Figure 16 It is the second of the timing schematic diagrams of a detection method provided by an embodiment of the present application. Detailed implementation manners

[0045] Next, the technical solutions in some embodiments will be clearly and completely described in conjunction with the accompanying drawings in some embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0046] Multiple signals in some embodiments have a first level and a second level. The first level and the second level only represent that the level of the signal has two states, and do not represent that the first level or the second level has a specific value.

[0047] The transistors in some embodiments can be thin film transistors (TFTs) or metal oxide semiconductor (MOS) field effect transistors. The control electrode of the transistor can be a gate, the first electrode can be a source or a drain, and the second electrode can be a drain or a source. For example, it can be an N-type TFT or a P-type TFT, and the embodiments of the present application do not limit this.

[0048] For the matrix piezoelectric pixel device in the related art, if the array scale of the device elements is 200 rows × 200 columns, when collecting ultrasonic signals emitted 80 mm away from the device, the sampling time at each sampling moment t is about 250 microseconds (μs) to 1150 μs, and the time required to complete M sampling moments is about 25 seconds (s) to 115 s, where M = 100. The sampling time is too long, and in scenarios with high real-time requirements such as ultrasonic medicine, the timeliness requirements cannot be met.

[0049] The current piezoelectric pixel device can be fabricated using a glass-based semiconductor process, such as a glass-based TFT device, and the matrix scale of the piezoelectric pixel device can be made very large. However, the switching rate and charge-discharge rate of the TFT device will affect the single-sampling time of the device, resulting in an increase in the total sampling time as the matrix scale increases, which limits its application in the field of ultrasonic detection.

[0050] Figure 1 It is one of the structural schematic diagrams of a detection panel provided by an embodiment of the present application, asFigure 1 As shown, the detection panel includes a multi-layer matrix device 101, and adjacent two-layer matrix devices 101 are coupled and connected through a coupling layer 102;

[0051] The matrix device 101 includes a plurality of array elements, the plurality of array elements are arranged in an array, and the array element includes a pixel circuit 1011 and a piezoelectric unit 1012, and the pixel circuit 1011 and the piezoelectric unit 1012 are electrically connected;

[0052] The multi-layer matrix device 101 includes one layer of reference device and at least one layer of equivalent device, and the array elements of the reference device and the array elements at the same position in the equivalent device are arranged in alignment along a first direction; wherein, the first direction is perpendicular to the surface of the multi-layer matrix device 101 for receiving ultrasonic signals.

[0053] The detection panel provided by the embodiment of the present application adopts the structure of the multi-layer matrix device 101, and each layer of matrix device 101 can be a matrix piezoelectric pixel device. A coupling layer 102 is provided in the multi-layer matrix device 101, and every two adjacent matrix piezoelectric pixel devices, that is, the matrix device 101 in this embodiment, can be coupled and connected through the coupling layer 102. Among them, the coupling layer 102 can adopt a material with viscosity to couple and bond the two-layer matrix device 101 together, such as coupling and bonding materials such as gel, silicone, and epoxy resin.

[0054] In some embodiments, each layer of matrix device 101 further includes a substrate, and a plurality of array elements of the matrix device 101 are arranged in an array on the substrate to form an array element matrix. Among them, the substrate can be a flexible substrate, which provides flexible support for the matrix device 101, so that the matrix device 101 has the advantage of being flexibly bendable. The flexible substrate can adopt polymer thin film materials such as polyimide (PI) and polydimethylsiloxane (PDMS), and the thickness range of the substrate is 10 micrometers (μm) to 500 μm.

[0055] In some embodiments, each array element includes a pixel circuit 1011 and a piezoelectric unit 1012, and the piezoelectric unit 1012 is located on the side of the pixel circuit 1011 away from the substrate. Each layer of matrix device 101 further includes a plurality of scan signal lines (Gate) and a plurality of read lines (Read), each row of array elements is electrically connected to the scan signal line of the corresponding row, and each column of array elements is electrically connected to the read line of the corresponding column. The corresponding row of array elements can be controlled to be turned on by sending a scan signal to the scan signal line, and the sampling signal corresponding to the turned-on array element can be read through the read line, so as to realize the row-column addressing and reading function.

[0056] Figure 2 It is a schematic diagram of the matrix structure of a matrix device 101 provided by the embodiment of the present application. As Figure 2As shown, the matrix device 101 includes a plurality of array elements arranged in an array in the row direction and the column direction, scanning signal lines Gate-1 to Gate-n extending respectively in the row direction, and read lines Read-1 to Read-n extending respectively in the column direction.

[0057] In some embodiments, the piezoelectric unit 1012 includes a first electrode, a piezoelectric layer, and a second electrode stacked in a direction away from the substrate. The first electrode is electrically connected to the pixel circuit 1011. The piezoelectric layer is used to achieve the acoustic-electric conversion of ultrasonic signals. The second electrode is a ground electrode. Among them, the first electrode can be a matrix structure. The first electrode can be made of conductive materials such as indium tin oxide (ITO), copper, gold, etc. The thickness range of the first electrode is 50 nanometers (nm) to 200 nm.

[0058] Among them, the piezoelectric layer can adopt a full-surface structure or a matrix structure. If both the first electrode and the piezoelectric layer are matrix structures, the matrix scales of the two can be kept consistent. The piezoelectric layer can be a flexible piezoelectric layer, so that the matrix device 101 can be flexibly bent. The piezoelectric layer is made of a piezoelectric material, such as thin film materials like polyvinylidene fluoride (PVDF), polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE), polyvinylidene fluoride-trifluoroethylene-chlorofluoroethylene (PVDF-TrFE-CFE), lead zirconate titanate (PZT), etc. The thickness range of the piezoelectric layer is 1 μm to 100 μm. The second electrode can be a full-surface structure and can be made of conductive materials such as ITO, copper, gold, etc. The thickness range of the second electrode is 50 nm to 200 nm.

[0059] In some embodiments, each layer of the matrix device 101 further includes a protective layer. The protective layer provides insulation protection for the entire matrix device 101 and can also prevent the device from being directly damaged by external forces, etc. The protective layer can adopt polymer thin film materials such as polyimide (PI), polydimethylsiloxane (PDMS), etc. The thickness range of the protective layer is 10 μm to 500 μm.

[0060] Figure 3 is a schematic diagram of the film layer structure of a matrix device 101 provided by an embodiment of the present application. As Figure 3 shown, the matrix device 101 is composed of a flexible substrate, a pixel circuit 1011, a first electrode, a flexible piezoelectric layer, a second electrode, and a protective layer. The matrix device 101 provided by this embodiment has the advantages of a large detection area, a high array density, and being flexibly bendable, and can be widely applied in fields such as wearable ultrasound and 3D ultrasound imaging.

[0061] In some embodiments, one layer of the multi-layer matrix device 101 in the multi-layer matrix device 101 is used as a reference device, and the matrix devices 101 in the multi-layer matrix device 101 other than the reference device are used as equivalent devices corresponding to the reference device, that is, the multi-layer matrix device 101 includes one layer of reference device and at least one layer of equivalent device. For example, if the number of layers of the multi-layer matrix device 101 is 2, the detection panel includes one layer of reference device and one layer of equivalent device; if the number of layers is 3, the detection panel includes one layer of reference device and two layers of equivalent devices. Among them, the device specifications of each matrix device 101 in the multi-layer matrix device 101 are the same. For example, when any two matrix devices 101 are compared, the array specifications such as the element size, element pitch, array scale, and device thickness of the two are the same. Therefore, the device specifications of the reference device and the equivalent device are the same.

[0062] Figure 4 It is the second structural schematic diagram of a detection panel provided by an embodiment of the present application. As Figure 4 shown, the detection panel includes three layers of matrix devices 101, namely the first matrix device, the second matrix device, and the third matrix device. A coupling layer 102 is provided between every two adjacent layers of matrix devices 101. The first coupling layer is between the first matrix device and the second matrix device, and the second coupling layer is between the second matrix device and the third matrix device. Among them, the coupling layer 102 is a coupling adhesive layer, and two adjacent layers of matrix devices 101 are bonded together through the coupling adhesive layer. As Figure 4 shown, the device scales of the three layers of matrix devices 101 are the same, and each layer of matrix device 101 includes Figure 2 a plurality of elements, a plurality of scan signal lines, and a plurality of read lines arranged in an array as shown.

[0063] In some embodiments, any one layer of the three-layer matrix device 101 as shown in Figure 4 can be used as a reference device, and the other two layers of matrix devices 101 are used as equivalent devices corresponding to the reference device. For example, the second matrix device located in the middle of the three-layer matrix device 101 can be used as a reference device, or the first matrix device or the third matrix device located on the outside of the three-layer matrix device 101 can be used as a reference device. The embodiments of the present application do not limit this.

[0064] In some embodiments, the first direction is perpendicular to the surface of the multi-layer matrix device 101 that receives ultrasonic signals. When the detection panel receives ultrasonic signals, usually the matrix device 101 closer to the ultrasonic source in the multi-layer matrix device 101 receives the ultrasonic signals first. Therefore, in this embodiment, the surface of the multi-layer matrix device 101 that receives ultrasonic signals can be the surface of the matrix device 101 closer to the ultrasonic source in the multi-layer matrix device 101.

[0065] Alternatively, when the detection panel samples the ultrasonic signal, the reference device is usually used as the reference plane (or reference measurement plane), and each element of the reference device serves as a reference point of the reference plane. Therefore, in this embodiment, the surface of the multi-layer matrix device 101 that receives the ultrasonic signal can be the surface of the reference device on the side close to the ultrasonic source, and the first direction is perpendicular to the surface of the reference device on the side close to the ultrasonic source. This is only an example, and the embodiments of the present application are not limited thereto.

[0066] In some embodiments, for a preset plurality of sampling times, the plurality of sampling times can be allocated to the reference device and the equivalent device in the multi-layer matrix device 101. Through the cooperation of the reference device and the equivalent device, the sampling of the ultrasonic signal received by the detection panel is completed at the plurality of sampling times. Each sampling time is sampled by at most one layer of the matrix device 101, and each layer of the matrix device 101 can be sampled at different sampling times.

[0067] In this way, compared with the related art in which the ultrasonic signal is sampled by a single matrix piezoelectric pixel device at each sampling time, the detection panel provided in this embodiment can complete the sampling work for all sampling times through the cooperation of the reference device and the equivalent device in the multi-layer matrix device 101. For each layer of the matrix device 101, the number of sampling times that need to work is reduced, and the overall sampling time is shortened. Therefore, the sampling efficiency of the ultrasonic signal can be improved.

[0068] Specifically, each reference point in the reference plane corresponding to the reference device has an equivalent measurement point at the same position in the equivalent measurement plane corresponding to the equivalent device, and the equivalent measurement point is an element of the equivalent device. If the element in the reference device is called a reference element, then the element at the same position in the equivalent device is the equivalent element corresponding to the reference element. The reference element of the reference device and the equivalent element at the same position in the equivalent device are arranged in alignment along the first direction, so that the elements in the reference device and the elements in the equivalent device are in one-to-one correspondence, thereby setting the equivalent measurement point corresponding to the reference point of the reference plane in the equivalent measurement plane corresponding to each equivalent device.

[0069] Among them, if the multi-layer matrix device 101 includes one layer of equivalent device, each reference plane has one equivalent measurement plane, and each reference point has one equivalent measurement point. If the multi-layer matrix device 101 includes two or more layers of equivalent devices, each reference plane has two or more equivalent measurement planes, and each reference point has two or more equivalent measurement points.

[0070] In the embodiments of the present application, the detection panel includes multiple layers of matrix devices 101. Adjacent layers of matrix devices 101 are coupled and connected through a coupling layer 102, so that the multiple layers of matrix devices 101 form an integral whole. The matrix device 101 includes a plurality of array elements. The plurality of array elements are arranged in an array. The array element includes a pixel circuit 1011 and a piezoelectric unit 1012. The pixel circuit 1011 and the piezoelectric unit 1012 are electrically connected. The ultrasonic beam can be sampled through the array of array elements of the matrix device 101, and the pixel circuit 1011 and the piezoelectric unit 1012 in the array element complete the acoustic-electric conversion. The multiple layers of matrix devices 101 include one layer of reference device and at least one layer of equivalent device. The array elements of the reference device and the array elements at the same position in the equivalent device are arranged in alignment in a first direction. The first direction is perpendicular to the surface of the multiple layers of matrix devices 101 for receiving ultrasonic signals, so that the array of array elements in the reference device and the array of array elements in the equivalent device can be roughly aligned in the first direction. By sampling the ultrasonic signal through the multiple layers of matrix devices 101, compared with sampling the ultrasonic signal by a single device in the related art, in this embodiment, the reference device and the equivalent device can sample at different sampling times, and the multiple layers of matrix devices 101 complete the sampling work at all sampling times, which can shorten the overall sampling time. Therefore, the sampling efficiency of the ultrasonic signal can be improved, and the detection effect of the detection panel can be improved.

[0071] Optionally, the alignment deviation between the array elements of the reference device and the array elements arranged in alignment in the equivalent device is less than a first wavelength; wherein, the first wavelength is equal to half of the wavelength of the ultrasonic signal.

[0072] In some embodiments, the array elements of the reference device are reference array elements, and the array elements arranged in alignment with the reference array elements in the equivalent device are equivalent array elements. The alignment deviation between the reference array element and the equivalent array element represents the offset distance between the two in a second direction. The second direction is perpendicular to the first direction. Wherein, if the first direction is perpendicular to the surface of the reference device close to the ultrasonic source, the second direction can be parallel to the surface of the reference device close to the ultrasonic source.

[0073] For example, the reference surface is the surface of the reference device close to the ultrasonic source, the equivalent measurement surface is the surface of the equivalent device close to the ultrasonic source, the reference surface corresponding to the reference device and the equivalent measurement surface corresponding to the equivalent device are parallel to each other, and the second direction includes any direction parallel to the reference surface and the equivalent measurement surface.

[0074] Wherein, the offset distance between the reference array element and the equivalent array element in the second direction can be the offset distance between the center points of the reference array element and the equivalent array element in the second direction, or, it can be the offset distance between the same-side edges of the reference array element and the equivalent array element in the second direction. This is only an example here, and the embodiments of the present application do not limit this.

[0075] In some embodiments, the ultrasonic signal is sampled multiple times by the reference points on the reference plane and the equivalent measurement points on the equivalent measurement plane. To improve the sampling accuracy, it is necessary to reduce the position deviation between the reference point and the equivalent measurement point, that is, to reduce the alignment deviation between the reference array element and its equivalent array element. In this embodiment, the alignment accuracy of the array elements needs to be better than λ / 2, where λ represents a wavelength of the ultrasonic signal, that is, the first wavelength is equal to λ / 2. The alignment deviation between the reference array element and its equivalent array element is less than λ / 2. In this way, the alignment accuracy between the reference array element and the equivalent array element can be improved, which is beneficial to improving the sampling accuracy of the detection panel.

[0076] Figure 5 is a schematic diagram of the detection of ultrasonic signals by a detection panel provided by an embodiment of the present application. As Figure 5 shown, when the ultrasonic source transmits ultrasonic waves and propagates in a three-dimensional (3D) space, due to the beam directivity and attenuation characteristics, there may be differences in the sound pressure magnitude, waveform phase, etc. at different positions. In this embodiment, in order to avoid excessive differences between the ultrasonic signals received by the three-layer matrix device 101, such as excessive differences between the ultrasonic signals received by the array element A, the array element B, and the array element C, which affect the accuracy of the sampling signal, the distance between the reference device and the equivalent device can be limited.

[0077] Optionally, the distance between the same film layers of the reference device and the equivalent device in the first direction is not greater than the wavelength of the ultrasonic signal.

[0078] In some embodiments, the distance between the reference device and each equivalent device is not greater than the wavelength (λ) of the ultrasonic signal. The distance between the reference device and any equivalent device can be the distance between the same film layers of the reference device and the equivalent device in the first direction. The film layer can be any layer of the substrate, the pixel circuit 1011, the first electrode, the flexible piezoelectric layer, the second electrode, and the protective layer, and the embodiments of the present application do not limit this.

[0079] Among them, if the reference device is located in the middle position of the multi-layer matrix device 101, the distances between the reference device and the equivalent devices on both sides of itself are not greater than λ. If the reference device is located outside the multi-layer matrix device 101, for example Figure 4 the first matrix device or the third matrix device in, the distances between the reference device and the equivalent devices on one side of itself are not greater than λ.

[0080] In a specific implementation manner, the piezoelectric unit 1012 includes a first electrode and a piezoelectric layer stacked, the first electrode is located on the side close to the pixel circuit 1011, and the first electrode is electrically connected to the pixel circuit 1011; the distance between the piezoelectric layers of the reference device and the equivalent device in the first direction is not greater than the wavelength of the ultrasonic signal.

[0081] Figure 6It is a schematic diagram of the film layer structure of a detection panel provided by an embodiment of the present application. As Figure 6 shown, the detection panel includes a three-layer matrix device 101 as Figure 4 shown and two coupling layers 102, and each layer of the matrix device 101 adopts a film layer structure as Figure 3 shown. Figure 6 Among them, the second matrix device is the reference device, the first matrix device and the third matrix device are equivalent devices, and the distance between the piezoelectric layers of the first matrix device and the piezoelectric layer of the second matrix device in the first direction is called the piezoelectric layer spacing, and the piezoelectric layer spacing is not greater than the wavelength (λ) of the ultrasonic signal. Similarly, the piezoelectric layer spacing between the second matrix device and the third matrix device is also not greater than λ.

[0082] In another specific embodiment, the total thickness of the film layer between the reference device and the equivalent device is the first thickness, and the first thickness is not greater than the wavelength of the ultrasonic signal; wherein, the total thickness of the film layer includes the thickness of the reference device itself and the thickness of other film layers between the reference device and the equivalent device, and the other film layers include the matrix device 101 and the coupling layer 102.

[0083] In some embodiments, taking the three-layer matrix device 101 as Figure 6 shown as an example, the second matrix device is the reference device, and the first matrix device and the third matrix device are equivalent devices. The first thickness can be expressed by the following formula (1):

[0084] d 1 +d 2 ≤λ (1)

[0085] wherein, d 1 represents the thickness of the matrix device 101, d 2 represents the thickness of the coupling layer 102, and λ represents the wavelength of the ultrasonic signal.

[0086] Optionally, the detection panel satisfies the following formula:

[0087] N×d 1 +(N - 1)×d 2 =(i + 1 / 4)×λ (2)

[0088] wherein, N represents the number of layers of the multi-layer matrix device 101, d 1 represents the thickness of the matrix device 101, d 2 represents the thickness of the coupling layer 102, λ represents the wavelength of the ultrasonic signal, and i is a non-negative integer.

[0089] In some embodiments, in order to ensure sound wave propagation and reduce sound wave attenuation, the detection panel needs to have good sound transmission, so the detection panel needs to satisfy formula (2). In formula (2), λ can be obtained by an ultrasonic wavelength detection tool, d 1and d 2 can be obtained by detecting the thicknesses of the matrix device 101 and the coupling layer 102. i is a non - negative integer, and i can take values "0, 1, 2...". The smaller the value of i, the better. In practical applications, by selecting a reasonable number of device layers N, the thickness d of the matrix device 101 can be optimized 1 and the thickness d of the coupling layer 102 2 satisfy formula (2), where the value of i can be adjusted by adjusting the thickness d of the coupling layer 102 2 to adjust the value of i.

[0090] Optionally, the acoustic impedance of the coupling layer 102 is approximately equal to the acoustic impedance of the matrix device 101.

[0091] In some embodiments, in order to make the detection panel have good sound permeability, the acoustic impedance of the coupling layer 102 in the detection panel needs to be approximately equal to the acoustic impedance of each layer of the matrix device 101. For example, if the coupling layer 102 is a coupling adhesive layer and the matrix device 101 is a matrix piezoelectric pixel device, then the acoustic impedance of the coupling adhesive layer is the same as or close to the acoustic impedance of the matrix piezoelectric pixel device.

[0092] In a specific implementation manner, each layer of the matrix device 101 further includes a substrate, and the substrate is located on the side of the pixel circuit 1011 away from the piezoelectric unit 1012; the material of the coupling layer 102 is substantially the same as the material of the substrate. In this embodiment, in each layer of the matrix device 101, the thickness of the substrate is much greater than the thicknesses of film layers such as the piezoelectric layer and the pixel circuit 1011. Therefore, the acoustic impedance of the matrix device 101 is mainly determined by the substrate material. Therefore, the material of the coupling layer 102 can adopt the substrate material. For example, the flexible substrate uses polymer thin - film materials such as polyimide (PI) and polydimethylsiloxane (PDMS). For example, the coupling adhesive layer adopts the same material system as the substrate. The coupling adhesive layer first bonds the matrix device 101 and then cures, which can improve the stability of the multi - layer matrix device 101.

[0093] Figure 7 is a schematic diagram of the circuit structure of an array element provided by an embodiment of the present application. As Figure 7As shown, the array element includes a piezoelectric unit 1012 and a pixel circuit 1011. The piezoelectric unit 1012 includes a first electrode, a piezoelectric layer, and a second electrode. The pixel circuit 1011 includes thin film transistors (TFTs) T1 to T4 and a capacitor C1. The control electrode of transistor T1 is electrically connected to the reset signal line Vrst. The first pole of transistor T1 is electrically connected to node N1. The second pole of transistor T1 is electrically connected to the bias voltage signal line Vbias. The control electrode of transistor T2 is electrically connected to the control signal line Vclose. The first pole of transistor T2 is electrically connected to node N1. Node N1 is also electrically connected to the first electrode of the piezoelectric unit 1012. The second pole of transistor T2 is electrically connected to node N2. The control electrode of transistor T3 is electrically connected to node N2. The first pole of transistor T3 is electrically connected to the power supply signal line VDD. The second pole of transistor T3 is electrically connected to the first pole of transistor T4.

[0094] As Figure 7 shown, the control electrode of transistor T4 is electrically connected to the scan signal line Gate. The second pole of transistor T4 is electrically connected to the read line Read. Node N2 is also electrically connected to the storage capacitor C1. The storage capacitor C1 can store the charge at node N2. One sampling process can include a transmission stage, a sampling stage, a holding stage, and a readout stage. In the holding stage, the sampling signal corresponding to the array element can be stored in the storage capacitor C1, and then in the readout stage, the scan signal transmitted through the scan signal line Gate turns on transistor T4, and the sampling signal is read out through the read line Read.

[0095] Optionally, the matrix device 101 further includes a control signal line; the pixel circuit 1011 in the array element includes a control transistor and a storage capacitor. The piezoelectric unit 1012 includes a first electrode and a piezoelectric layer arranged in a stacked manner. The first electrode is located on the side of the piezoelectric unit 1012 close to the pixel circuit 1011;

[0096] The control electrode of the control transistor is electrically connected to the control signal line. The first pole of the control transistor is electrically connected to the storage capacitor. The second pole of the control transistor is electrically connected to the first electrode; wherein, the control signal lines to which the control transistors in different layer matrix devices 101 are electrically connected are independent of each other.

[0097] In some embodiments, the piezoelectric unit 1012 includes a first electrode and a piezoelectric layer arranged in a stacked manner. The first electrode is located on the side of the piezoelectric unit 1012 close to the pixel circuit 1011. The piezoelectric unit 1012 further includes a second electrode. The second electrode is located on the side of the piezoelectric unit 1012 away from the pixel circuit 1011. The second electrode can be a ground electrode. As Figure 7As shown, the pixel circuit 1011 includes a control transistor T2 and a storage capacitor C1. The control electrode of the control transistor T2 is electrically connected to the control signal line Vclose. The first pole of the control transistor T2 is electrically connected to the storage capacitor C1. The second pole of the control transistor is electrically connected to the first electrode of the piezoelectric unit 1012.

[0098] In some embodiments, each layer of the matrix device 101 further includes a control signal line Vclose. As Figure 7 shown, by sending a control signal to the control signal line Vclose, the control transistor T2 can be turned on or off. When the control transistor T2 is turned on, the first electrode of the piezoelectric unit 1012 is electrically connected to the storage capacitor C1. When the control transistor T2 is turned off, the first electrode of the piezoelectric unit 1012 is disconnected from the storage capacitor C1. In this embodiment, the control signal lines Vclose to which the control transistors in different layers of the matrix device 101 are electrically connected are independent of each other. In this way, independent control signals can be provided to each layer of the matrix device 101, so that the control transistor T2 can be turned on or off, and the moments of sending control signals to the control signal line Vclose between each layer of the matrix device 101 do not affect each other, making the control of the detection panel more flexible.

[0099] The embodiment of the present application further provides a detection device, which includes a detection panel as described in the foregoing embodiment and a control circuit, and the control circuit is electrically connected to the detection panel.

[0100] In some embodiments, each layer of the matrix device 101 includes a reset signal line Vrst, a bias voltage signal line Vbias, a control signal line Vclose, a scan signal line Gate, a power supply signal line VDD, and a read line Read. The control circuit can be electrically connected to various control signal lines in each layer of the matrix device 101 respectively, and send various control signals to the pixel circuits 1011 of each element in the matrix device 101 to complete the sampling of the ultrasonic signal.

[0101] In some embodiments, the detection device may further include a read circuit, and the read circuit can be electrically connected to the read lines Read in each layer of the matrix device 101 respectively to read the sampling signals corresponding to each layer of the matrix device 101. Among them, the number of read circuits is not limited. One read circuit can be provided corresponding to each layer of the matrix device 101, so as to synchronously read the sampling signals of multiple layers of the matrix device 101, which can improve the reading speed of the sampling signals and the sampling efficiency of the detection device.

[0102] The detection device provided by the embodiment of the present application can achieve the same technical effects as the detection panel in the foregoing embodiment. To avoid repetition, it will not be described in detail here.

[0103] Currently, in the field of ultrasonic detection and imaging, ultrasonic waves are usually collected at multiple measurement points within a two-dimensional measurement plane, and the spacing between the measurement points is not greater than λ / 2, where λ is the ultrasonic wavelength, so as to obtain a three-dimensional matrix signal on the measurement plane. The signal structure is nx×ny×nt, where nx and ny respectively represent the measurement points in the nx-th row and the ny-th column, and nt represents the nt-th sampling moment.

[0104] When collecting ultrasonic signals with a frequency of f0 as shown in Figure 8 by a single matrix piezoelectric pixel device, according to the Nyquist sampling theorem, in order to obtain a sampling signal with basically no distortion, the device needs to sample at a sampling frequency fs, where the sampling frequency fs is not less than 4 times the ultrasonic signal frequency, that is, fs≥4f0. When the device operates at the lowest sampling frequency of 4f0, the sampling moments are the moments marked as "t1, t2, t3..." as shown in Figure 8 , and the obtained sampling signal is as shown in Figure 9 . Figure 8 And Figure 9 In, the abscissa is the sampling time and the ordinate is the signal amplitude.

[0105] Figure 10 FIG. is a schematic diagram of the steps of a detection method provided by an embodiment of the present application. The detection method is used to control a detection panel as described in the foregoing embodiment. The detection method includes:

[0106] Step S1, controlling the reference device to sample the ultrasonic signal received by the detection panel at the reference moment in each sampling group, and controlling the equivalent device to sample the ultrasonic signal at the corresponding target moment in each sampling group; wherein, the preset M sampling moments are divided into multiple sampling groups, and each sampling group includes N sampling moments, and N is equal to the number of layers of the multi-layer matrix device 101; the time sequence of the reference moment and the target moment in the sampling group corresponds one-to-one with the reception sequence of the reference device and the equivalent device for the ultrasonic signal in the multi-layer matrix device 101.

[0107] In some embodiments, the execution subject of the detection method may be the control circuit in the detection device described in the foregoing embodiment. The control circuit controls the detection panel to sample the ultrasonic signal, such as sampling the ultrasonic signal as shown in Figure 8 to obtain a sampling signal as shown in Figure 9 . When the detection panel operates at a certain sampling frequency, the sampling process can preset M sampling moments, such as the sampling moments marked in Figure 8 .

[0108] In some embodiments, the sampling moment is the moment when a control signal is sent to the control signal line Vclose of the detection panel to turn off the control transistor T2, denoted as tclose. For example, tclose can take values Figure 8"t1, t2, t3..." as shown. One sampling process may include a transmission stage, a sampling stage, a holding stage, and a readout stage. In the transmission stage, the transmission (Tx) system of the ultrasonic source, such as a sound source transducer, transmits a pulsed excitation signal with a frequency of f0 at the "0" moment, and the control circuit synchronously turns on the reset (Vrst) signal and the control (Vclose) signal, so that Figure 7 the transistors T1 and T2 shown are turned on. In the sampling stage, at the moment of t1, the control circuit turns off the Vclose signal and turns off the Vrst signal about 1 μs to 10 μs in advance, so that the transistors T1 and T2 are turned off. Among them, turning off the Vrst signal in advance can ensure that when the Vclose signal is turned off, the entire matrix device 101 is reset and the array elements are in the same state.

[0109] In the holding stage, the moment when the Vclose signal is turned off, i.e., the sampling moment tclose of this embodiment, the sampling signal of the array element for the ultrasonic signal is stored in the storage capacitor C1. In the readout stage, within a time range of about 1 μs to 10 μs, scan signals are sequentially sent to the scan signal lines Gate-1 to Gate-n. The pulse length tg of the scan signal is about 1 μs to 10 μs, limited by the readout speed of the readout circuit, and the interval period between adjacent row scan signals is about tg + 1 μs. When each row of Gate channels is opened, each column of Read channels is opened synchronously or slightly later. The single pulse width t_r of the Read channel is not greater than t_g, and the pulse period of the Read channel is consistent with the interval period of the scan signal Gate, about tg + 1 μs.

[0110] Currently, when using a single piezoelectric pixel device with a matrix size of n×n to collect Figure 8 the ultrasonic signal as shown, for a single device to complete the signal collection at M sampling moments, the total time consumption is as shown in the following formula (3):

[0111]

[0112] where, t 总 represents the total time consumption to complete all sampling moments, with the unit of second (s). t i represents the time required for each sampling moment, M represents the i-th sampling moment among the preset M sampling moments, n represents the number of rows of the matrix, and tg + 1 μs represents the interval period of the scan signal. When using a single device, the time required for each sampling moment is about 250 μs to 1150 μs, and the total time consumption to complete 100 sampling moments is about 25 s to 115 s. The sampling time is long and the sampling efficiency is low.

[0113] In some embodiments, M preset sampling moments are divided into multiple sampling groups in chronological order. Each sampling group includes N sampling moments, where N is equal to the number of layers of the multi-layer matrix device 101. If M / N has a remainder, the number of sampling moments in the last sampling group may be less than N. The N sampling moments in each sampling group are arranged in ascending order of time, and the N-layer matrix device 101 is arranged in the order of the reception sequence of the ultrasonic signals by each layer of the matrix device 101. In this embodiment, the N sampling moments in each sampling group are sequentially assigned to the N-layer matrix device 101, so that the N sampling moments in each sampling group correspond one-to-one to the N-layer matrix device 101.

[0114] In some embodiments, the N-layer matrix device 101 includes 1 layer of reference device and N-1 layers of equivalent devices. In each sampling group, the sampling moment corresponding to the reference device is called the reference moment, and the sampling moments corresponding to the equivalent devices are denoted as target moments. In this embodiment, the chronological order of the reference moment and the target moments in each sampling group corresponds one-to-one to the reception sequence of the ultrasonic signals by the reference device and the equivalent devices.

[0115] In some embodiments, the control circuit sends a control signal to the control signal line Vclose in the reference device to turn off the control transistor T2 at the reference moment corresponding to the reference device in each sampling group, so that the control transistor T2 in the pixel circuit 1011 of each element disconnects the storage capacitor C1 of the pixel circuit 1011 and the first electrode of the piezoelectric unit 1012, thereby storing the sampling signal corresponding to the element in the storage capacitor C1. Furthermore, in the reading stage of the sampling process corresponding to this sampling group, a scanning signal can be sent to the scanning signal line Gate in the reference device to turn on the transistor T4 of the pixel circuit 1011, and the sampling signal is read through the reading line Read to complete the sampling process of the ultrasonic signal by the reference device.

[0116] In some embodiments, the control circuit sends a control signal to the control signal line Vclose in the equivalent device to turn off the control transistor T2 at the target moment corresponding to the equivalent device in each sampling group, so that the control transistor T2 in the pixel circuit 1011 of each element disconnects the storage capacitor C1 of the pixel circuit 1011 and the first electrode of the piezoelectric unit 1012, thereby storing the sampling signal corresponding to the element in the storage capacitor C1. Furthermore, in the reading stage of the sampling process corresponding to this sampling group, a scanning signal can be sent to the scanning signal line Gate in the equivalent device to turn on the transistor T4 of the pixel circuit 1011, and the sampling signal is read through the reading line Read to complete the sampling process of the ultrasonic signal by the equivalent device.

[0117] In some embodiments, Figure 4Taking the three-layer matrix device 101 shown as an example, the second matrix device is used as the reference device, and the first matrix device and the third matrix device are used as the equivalent devices corresponding to the reference device. When using the three-layer matrix device 101 to Figure 8 sample the ultrasonic signal at the sampling times "t1, t2, t3..." shown, each sampling group includes 3 sampling times. For example, the three sampling times "t1, t2, t3" are the first sampling group. According to the order in which the first matrix device in the three-layer matrix device 101 receives the ultrasonic signal first, the time t1 can be allocated to the first matrix device, the time t2 can be allocated to the second matrix device, and the time t3 can be allocated to the third matrix device. And so on. For all sampling times, the times "t1, t4, t7..." can be allocated to the first matrix device, the times "t2, t5, t8..." can be allocated to the second matrix device, and the times "t3, t6, t9..." can be allocated to the third matrix device.

[0118] In this way, in each sampling group, a sampling process is completed according to the transmission stage, sampling stage, holding stage, and readout stage. The Figure 4 three-layer matrix device 101 shown samples the ultrasonic signal respectively to obtain a sampling signal. By adjusting the closing time of the control signal Vclose, that is, tclose, the sampling work for all sampling times can be realized.

[0119] Figure 11 is a schematic diagram of the sampling process of a piezoelectric pixel device for an ultrasonic signal in the related art. As Figure 11 shown, a single matrix piezoelectric pixel device needs to complete a sampling process at each sampling time to complete all nt samplings.

[0120] Figure 12 is a schematic diagram of the sampling process of a detection panel for an ultrasonic signal provided by an embodiment of the present application. As Figure 12 shown, taking the three-layer matrix device 101 as an example, each sampling group corresponds to a sampling process, and the three-layer matrix device 101 completes the sampling work at the three sampling times in the sampling group respectively. Therefore, in this embodiment, through the collaborative sampling of the N-layer matrix device 101, the nt samplings of a single device can be reduced to nt / N samplings of the N-layer matrix device 101. nt / N can be rounded up, and a sampling result of nx×ny×nt can be obtained. Since the sampling time is shortened, the sampling efficiency can be improved.

[0121] Optionally, controlling the equivalent device to sample the ultrasonic signal at the target time corresponding to each sampling group includes:

[0122] Sampling the ultrasonic signal at the equivalent moment corresponding to each equivalent device in each sampling group; wherein, the equivalent moment is equal to the sum of the target moment and the target time difference; the absolute value of the target time difference is the ratio of the distance between the equivalent device and the reference device along the first direction to the speed of sound;

[0123] Wherein, the target time difference corresponding to the equivalent device that receives the ultrasonic signal earlier than the reference device is negative, and the target time difference corresponding to the equivalent device that receives the ultrasonic signal later than the reference device is positive.

[0124] In some embodiments, when using Figure 4 the three-layer matrix device 101 shown in Figure 8 to collect Figure 13 the ultrasonic signal shown in Figure 13 (a) is the waveform of the ultrasonic signal, Figure 13 (b) is the sampling result of a single device, Figure 13 (c) is the sampling result of the three-layer matrix device 101. It can be seen that Figure 13 the sampling result of (c) is seriously distorted compared with Figure 13 (a). This is mainly because when the three-layer matrix device 101 samples completely according to the preset sampling moment, the spatial spacing of the three-layer matrix device 101 is not considered.

[0125] As Figure 14 shown, the ultrasonic beam emitted by the ultrasonic source passes through the three-layer matrix device 101 shown in Figure 4 The second matrix device receives the ultrasonic signal at time t2, and the first matrix device and the third matrix device respectively receive the ultrasonic signals of the second matrix device at times t1 and t3. Then the time for the ultrasonic signal to reach the first matrix device at time t1 is earlier than that of the second matrix device by d / c, and the time for the ultrasonic signal to reach the third matrix device at time t3 is later than that of the second matrix device by d / c, as shown in the following formula (4):

[0126]

[0127] Wherein, d represents the distance between the equivalent device and the reference device along the first direction, and c is the speed of sound.

[0128] In some embodiments, the absolute value of the target time difference is the ratio d / c of the distance d between the equivalent device and the reference device along the first direction to the speed of sound c. The target time difference corresponding to the equivalent device that receives the ultrasonic signal earlier than the reference device is negative, such as Figure 4 the target time difference corresponding to the first matrix device in Figure 4The target time difference corresponding to the third matrix device is d / c. And the equivalent time corresponding to each equivalent device should be the sum of the target time and the target time difference in the sampling group, as shown in formula (4).

[0129] In some embodiments, the control circuit sends a control signal to the control signal line Vclose in the equivalent device at the equivalent time corresponding to each sampling group to turn off the control transistor T2, so that the control transistor T2 of the pixel circuit 1011 in each element disconnects the storage capacitor C1 of the pixel circuit 1011 and the first electrode of the piezoelectric unit 1012, thereby storing the sampling signal corresponding to the element in the storage capacitor C1. Furthermore, in the reading stage of the sampling process corresponding to this sampling group, a scanning signal can be sent to the scanning signal line Gate in the equivalent device to turn on the transistor T4 of the pixel circuit 1011, and the sampling signal can be read through the read line Read, completing the sampling process of the equivalent device for the ultrasonic signal. In this way, the sampling signal can be prevented from being severely distorted due to the influence of the device pitch, and the accuracy of the sampling result can be improved.

[0130] Optionally, controlling the reference device to sample the ultrasonic signal received by the detection panel at the reference time in each sampling group includes:

[0131] At the reference time in each sampling group, send a control signal with a first level to the control signal line corresponding to the reference device, so that the control transistor of the pixel circuit 1011 in the element of the reference device disconnects the storage capacitor of the pixel circuit 1011 and the first electrode of the piezoelectric unit 1012, so as to store the sampling signal corresponding to the element in the storage capacitor;

[0132] Controlling the equivalent device to sample the ultrasonic signal at the target time corresponding to the sampling group includes:

[0133] At the target time corresponding to each sampling group, send a control signal with a first level to the control signal line corresponding to the equivalent device, so that the control transistor of the pixel circuit 1011 in the element of the equivalent device disconnects the storage capacitor of the pixel circuit 1011 and the first electrode of the piezoelectric unit 1012, and stores the sampling signal corresponding to the element in the storage capacitor.

[0134] In some embodiments, the preset sampling moment is the moment tclose when the control circuit sends a control signal to the control signal line Vclose of the detection panel to turn off the control transistor T2. At the reference moment in each sampling group, a control signal with a first level is sent to the control signal line Vclose corresponding to the reference device, where the first level is opposite to the effective level of the control transistor T2. For example, if the control transistor T2 is an N-type transistor, the first level is a low level; if the control transistor T2 is a P-type transistor, the first level is a high level. The control signal with the first level can turn off the control transistor T2 in the pixel circuit 1011 of the array element of the reference device, thereby disconnecting the storage capacitor C1 of the pixel circuit 1011 from the first electrode of the piezoelectric unit 1012 to store the sampling signal corresponding to the array element in the storage capacitor C1.

[0135] In some embodiments, at the target moment corresponding to the equivalent device in each sampling group, a control signal with a first level is sent to the control signal line Vclose corresponding to the equivalent device. Considering the influence of device pitch and avoiding sampling signal distortion, at the equivalent moment corresponding to the equivalent device in each sampling group, a control signal with a first level can be sent to the control signal line Vclose corresponding to the equivalent device, so that the control transistor T2 in the pixel circuit 1011 of the array element of the equivalent device is turned off, thereby disconnecting the storage capacitor C1 of the pixel circuit 1011 from the first electrode of the piezoelectric unit 1012 to store the sampling signal corresponding to the array element in the storage capacitor C1.

[0136] In some embodiments, since the preset sampling moment is directly related to the moment tclose, when the multi-layer matrix device 101 samples, independent Vclose signals need to be sent to each matrix device 101, while the signals such as Vtx, Vrst, Vbias, Vdd, Gate, and Read have no differences, where the Vtx signal is a control signal for controlling the ultrasonic source to emit ultrasonic waves.

[0137] Figure 15 It is one of the timing schematic diagrams of a detection method provided by an embodiment of the present application. As Figure 15 shown, taking the three-layer matrix device 101 shown in Figure 4 as an example, ultrasonic signals are sampled in each sampling group. At the "0" moment of the sampling group, the Tx system of the sound source transducer is controlled by the Vtx signal to emit a pulse excitation signal with a duration of t_us, and the control circuit synchronously sends a high-level reset (Vrst) signal and a high-level control (Vclose) signal to the three-layer matrix device 101, so that Figure 7 the transistors T1 and T2 shown are turned on. Among them, the Vclose signals corresponding to the three-layer matrix device 101 are independent of each other, which are Vclose-1, Vclose-2, and Vclose-3 signals respectively.

[0138] Then, at the trst moment, the Vrst signal is turned off, i.e., a low-level Vrst signal is sent. Then, at the tclose - T / 4 - d / c moment, the Vclose-1 signal is turned off, i.e., a low-level Vclose-1 signal is sent. At the tclose moment, the Vclose-2 signal is turned off, i.e., a low-level Vclose-2 signal is sent. At the tclose + T / 4 + d / c moment, the Vclose-3 signal is turned off, i.e., a low-level Vclose-3 signal is sent. Among them, taking the sampling group "t1, t2, t3" as an example, the tclose - T / 4 - d / c moment is the t1 moment in the sampling group, the tclose moment is the t2 moment in the sampling group, and the tclose + T / 4 + d / c moment is the t3 moment in the sampling group. Figure 15 The bias voltage signal Vbias and the power supply signal line VDD are also shown. T / 4 represents the interval between two adjacent sampling moments among the preset M sampling moments, and each matrix device operates at a sampling frequency of 4f0.

[0139] Figure 16 It shows that in the readout stage of the sampling group, scan signals t_g1 to t_gn are sent to the scan signal lines Gate-1 to Gate-n, the transistor T4 of the pixel circuit 1011 in each row element is turned on, and the sampling signals t_r of each element are read out through each column read line Read-1 to Read-n, so that each matrix device 101 completes the sampling of the ultrasonic signal and obtains the sampling signal. For the reference device and the equivalent device to obtain the sampling signal, data fitting can be performed according to the sampling moments to obtain Figure 9 the signal waveform as shown, so as to complete the detection of Figure 8 the ultrasonic signal as shown.

[0140] Each embodiment in this specification is described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0141] Each embodiment in this specification is described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0142] Although the preferred embodiments of the embodiments of the present application have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concept. Therefore, the appended claims are intended to be interpreted to include the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present application.

[0143] Finally, it should also be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or terminal device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or terminal device comprising the element.

[0144] The above provides a detailed introduction to a detection panel, a detection device and a detection method provided by the present application. Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A detection panel, characterized in that: The detection panel includes a multi-layer matrix device, and two adjacent layers of the matrix devices are coupled and connected via a coupling layer; The matrix device comprises a plurality of array elements, the plurality of array elements are arranged in an array, the array elements comprise a pixel circuit and a piezoelectric unit, and the pixel circuit and the piezoelectric unit are electrically connected; The multilayer matrix device includes a layer of reference devices and at least one layer of equivalent devices, and the array elements of the reference device are aligned with the array elements at the same position in the equivalent device along a first direction; wherein the first direction is perpendicular to the surface of the multilayer matrix device that receives ultrasonic signals.

2. The detection panel according to claim 1, characterized in that: The alignment deviation between the array elements of the reference device and the array elements arranged in the equivalent device is less than a first wavelength; wherein the first wavelength is equal to half of the wavelength of the ultrasonic signal.

3. The detection panel according to claim 1, characterized in that: The distance between the same membrane layer of the reference device and the equivalent device along the first direction is not greater than the wavelength of the ultrasonic signal.

4. The detection panel according to claim 1, characterized in that: The detection panel satisfies the following formula: N×d1+(N-1)×d2=(i+1 / 4)×λ Wherein, N represents the number of layers of the multilayer matrix device, d1 represents the thickness of the matrix device, d2 represents the thickness of the coupling layer, λ represents the wavelength of the ultrasonic signal, and i is a non-negative integer.

5. The detection panel according to claim 1, characterized in that: The acoustic impedance of the coupling layer is substantially equal to the acoustic impedance of the matrix device.

6. The detection panel according to any one of claims 1 to 5, characterized in that: The matrix device further includes a control signal line; the pixel circuit in the array element includes a control transistor and a storage capacitor, the piezoelectric unit includes a first electrode and a piezoelectric layer stacked in layers, and the first electrode is located on a side of the piezoelectric unit close to the pixel circuit; The control electrode of the control transistor is electrically connected to the control signal line, the first electrode of the control transistor is electrically connected to the storage capacitor, and the second electrode of the control transistor is electrically connected to the first electrode; wherein the control signal lines electrically connected to the control transistors in different layers of the matrix device are independent of each other.

7. A detection device, characterized in that: The detection device comprises a detection panel as described in any one of claims 1 to 6, and a control circuit, wherein the control circuit is electrically connected to the detection panel.

8. A detection method, characterized in that: Used to control the detection panel as described in any one of claims 1 to 6, the detection method comprising: Controlling the reference device to sample the ultrasonic signal received by the detection panel at a reference time in each sampling group, and controlling the equivalent device to sample the ultrasonic signal at a corresponding target time in each sampling group; Among them, the preset M sampling moments are divided into a plurality of sampling groups, each sampling group includes N sampling moments, where N is equal to the number of layers of the multilayer matrix device; the time sequence of the reference moment and the target moment in the sampling group corresponds one-to-one to the order in which the reference device and the equivalent device in the multilayer matrix device receive the ultrasonic signal.

9. The detection method according to claim 8, characterized in that: The control equivalent device samples the ultrasonic signal at a target time corresponding to each sampling group, including: Controlling the equivalent device to sample the ultrasonic signal at the equivalent time corresponding to each sampling group; wherein the equivalent time is equal to the sum of the target time and the target time difference; the absolute value of the target time difference is the ratio of the distance between the equivalent device and the reference device along the first direction to the speed of sound; The target time difference corresponding to the equivalent device that receives the ultrasonic signal earlier than the reference device is negative, and the target time difference corresponding to the equivalent device that receives the ultrasonic signal later than the reference device is positive.

10. The detection method according to claim 8 or 9, characterized in that: The control reference device samples the ultrasonic signal received by the detection panel at a reference time in each sampling group, including: At a reference moment in each of the sampling groups, a control signal having a first level is sent to a control signal line corresponding to the reference device, so that a control transistor of a pixel circuit in an array element of the reference device disconnects a storage capacitor of the pixel circuit from a first electrode of a piezoelectric unit, so as to store a sampling signal corresponding to the array element in the storage capacitor; The control equivalent device samples the ultrasonic signal at a target time corresponding to the sampling group, including: At a target moment corresponding to each of the sampling groups, the control signal with the first level is sent to the control signal line corresponding to the equivalent device, so that the control transistor of the pixel circuit in the array element of the equivalent device disconnects the storage capacitor of the pixel circuit and the first electrode of the piezoelectric unit, and stores the sampling signal corresponding to the array element in the storage capacitor.

Images