TWI831032B - Ultrasonic fingerprint recognition assembly, electronic device, and ultrasonic fingerprint recognition method - Google Patents

Abstract

The present disclosure provides an ultrasonic fingerprint recognition assembly including a piezoelectric layer, a resonance electrode layer, a TFT array substrate, and a fingerprint recognition chip. The piezoelectric layer having a first surface and a second surface opposite to each other. The resonance electrode layer is on the first surface and includes a plurality of sub-electrodes spaced apart. Each of the plurality of sub-electrodes can be individually driven and activated and used to receive a driving signal according to a touch position. The TFT array substrate is on the second surface and includes a pixel circuit array and a receiving electrode array coupled to the piezoelectric layer. The TFT array substrate is used to couple out electrical signals. The fingerprint recognition chip is electrically connected to each of the plurality of sub-electrodes and is used to calculate according to the electrical signals for fingerprint recognition. The disclosure also provides an electronic device and an ultrasonic fingerprint recognition method.

Description

Ultrasonic fingerprint identification module, electronic device and ultrasonic fingerprint identification method

The present invention relates to the technical field of fingerprint identification, and in particular to an ultrasonic fingerprint identification module, an electronic device and an ultrasonic fingerprint identification method.

Fingerprint recognition is the classification and comparison of fingerprints to identify objects for identification. As one of the biometric identification technologies, fingerprint recognition technology has gradually matured in the new century and entered the field of human production and life. Compared with traditional optical fingerprint recognition technology and capacitive fingerprint recognition technology, ultrasonic fingerprint recognition technology has better penetration and higher security. Therefore, ultrasonic fingerprint identification technology has become one of the important development directions of fingerprint identification.

However, when the conventional ultrasonic fingerprint recognition technology is applied to electronic devices such as mobile phones, the fingerprint sensing area accounts for a small proportion of the entire screen. Users need to find the unlocking area through their own memory or the fingerprint area marked on the screen. When the proportion of the fingerprint sensing area is increased, problems such as greater power consumption and slow unlocking time will occur.

In view of this, it is necessary to provide an ultrasonic fingerprint recognition module that can meet the needs of large-screen ultrasonic fingerprint sensing, consumes less power, and has a fast unlocking time. In addition, the present invention also provides an ultrasonic fingerprint recognition device and electronic device with a fingerprint recognition function. equipment.

In one aspect, the present invention provides an ultrasonic fingerprint identification module, including: a piezoelectric layer having opposite first and second surfaces; a resonant electrode layer stacked on the first surface, and the resonant electrode layer has A plurality of sub-electrodes arranged at insulated intervals, each of the sub-electrodes can be independently driven and used to receive driving signals according to the touch position; A TFT array substrate is provided on one side of the second surface. The TFT array substrate includes a pixel circuit array and a receiving electrode array. The receiving electrode array is coupled to the piezoelectric layer. The resonant electrode layer and the The receiving electrode array cooperates with the piezoelectric layer to emit ultrasonic waves during the ultrasonic wave transmitting period, the resonant electrode layer cooperates with the piezoelectric layer to receive ultrasonic waves and convert them into electrical signals during the ultrasonic wave receiving period, and the TFT array substrate is used to couple out the an electrical signal; and a fingerprint recognition chip, electrically connected to each of the sub-electrodes, and the fingerprint recognition chip is used to perform fingerprint recognition calculations on the electrical signal.

On the other hand, an electronic device is provided, including: the above-mentioned ultrasonic fingerprint recognition module; a display module, the display module including a touch surface for receiving touch operations, the display module and the ultrasonic fingerprint recognition module The modules share the TFT array substrate, and the touch surface has a plurality of touch areas corresponding to a plurality of the sub-electrodes; a touch drive circuit is used to drive the touch surface when the touch surface is touched by a finger. The control driving circuit determines the touched touch area and outputs a touch signal carrying the touch area information; the ultrasonic driving circuit is coupled to the touch driving circuit and the sub-electrode, and the ultrasonic driving circuit is used to detect the touch area according to the The touch signal drives one or a plurality of the sub-electrodes.

On the other hand, an ultrasonic fingerprint identification method is provided. The ultrasonic fingerprint identification method includes the following steps: a touch drive circuit receives a touch operation and distinguishes one or multiple touch areas that are touched and outputs a touch signal; the ultrasonic drive circuit operates according to the The touch signal drives one or a plurality of sub-electrodes corresponding to the touch area; the piezoelectric layer sends out ultrasonic signals to the finger, and receives the ultrasonic signals reflected from the surface of the finger back to the piezoelectric layer and converts them into The electrical signal is output to the TFT array substrate; the TFT array substrate screens the electrical signal and transmits the screened electrical signal to the fingerprint recognition chip; the fingerprint recognition chip receives the screened electrical signal And perform fingerprint recognition calculation on the filtered electrical signals.

1: Electronic devices

3:Finger

10: Ultrasonic fingerprint recognition module

11: Resonance electrode layer

111: Sub-electrode

12: Piezoelectric layer

121: First surface

123: Second surface

13:Fingerprint recognition chip

14:TFT array substrate

15:Flexible circuit board

16: Flat layer

17:Protective layer

20:Display module

201:Touch surface

202:Touch area

21:Touch sensing structure

23:Display structure

30:Touch drive circuit

40: Ultrasonic drive circuit

141:Pixel circuit

142: Pixel circuit array

143: Receiving electrode

144: Receiving electrode array

145: pin

FIG. 1 is a schematic structural diagram of an electronic device provided by an embodiment of the present application.

Figure 2 is a schematic cross-sectional structural diagram of an ultrasonic fingerprint recognition module provided by an embodiment of the present application.

Figure 3 is a schematic diagram of the stacked structure of the ultrasonic fingerprint recognition module of Figure 2.

FIG. 4 is a schematic structural diagram of a part of the ultrasonic fingerprint recognition module of FIG. 2 .

Figure 5 Another part of the structure of the ultrasonic fingerprint recognition module in Figure 2

Figure 6a is a schematic diagram of a partial structure of the ultrasonic fingerprint recognition module provided by a modification of the present application when a finger is in contact.

Figure 6b is a schematic diagram of another partial structure of the ultrasonic fingerprint recognition module when a finger is in contact with the modified example of this application.

Figure 6c is a schematic diagram of another partial structure of the ultrasonic fingerprint recognition module when a finger is in contact with the modified example of the present application.

Figure 7 is a flow chart of an ultrasonic fingerprint identification method provided by an embodiment of the present application.

Embodiment 1

In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are some, but not all, of the embodiments of the present disclosure. Based on the described embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present disclosure.

Unless otherwise defined, technical terms or scientific terms used in this disclosure shall have the usual meaning understood by a person with ordinary skill in the art to which this disclosure belongs. "First", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprising" mean that the elements or things appearing before the word include the elements or things listed after the word and their equivalents, without excluding other elements or things. "Up", "down", "left", "right", etc. are only used to express relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

Throughout this description and the appended claims, certain words are used to refer to specific elements. Those skilled in the art will understand that manufacturers of electronic devices may refer to them by different names The same components, and this article does not intend to differentiate between components that have the same function but have different names. When the terms "comprises", "including" and/or "having" are used in this specification, they specify the presence of stated features, regions, steps, operations and/or elements but do not exclude one or more other features, regions, steps, operations and/or elements. , the existence or addition of regions, steps, operations, elements and/or combinations thereof. When an element such as a layer or region is referred to as being "on" or extending "on" another element (or a variation thereof), it can be directly on or extending directly onto the other element, Or there can be intervening elements between the two. On the other hand, when an element is referred to as being "directly on" or "extending directly on" another element (or variations thereof), there are no intervening elements present. Furthermore, when an element is referred to as being "coupled" to another element (or a variation thereof), it can be directly connected to the other element or indirectly connected (e.g., electrically connected) to the other element through the element or elements. .

Please refer to FIG. 1 . The electronic device 1 of this embodiment includes an ultrasonic fingerprint recognition module 10 , a display module 20 and a touch drive circuit 30 . The display module 20 includes a touch sensing structure 21 for implementing a touch function and a display structure 23 for displaying images. The display structure 23 may be one of a liquid crystal display structure, an organic light-emitting diode display structure, and a micro-inorganic light-emitting diode display structure. The display module 20 includes a touch surface 201 for receiving touch operations. The touch surface 201 has a plurality of touch areas 202 . The touch drive circuit 30 is used to determine the touched touch area 202 when the touch surface 201 is touched by the finger 3, and output a touch signal carrying information about the touch area 202.

The touch sensing structure 21 may be a mutual capacitive touch sensing structure, including a driving electrode (not shown) for receiving a touch driving signal, and a sensing device for sensing the received touch sensing signal. electrodes (not shown), where the touch drive signal is provided by the touch drive circuit 30, and the touch drive circuit 30 further receives and analyzes the touch sensing signal to obtain the contact coordinates, thereby determining the touched touch area. 202. The touch driving circuit 30 may be an integrated circuit (IC) communicatively connected with the touch sensing structure 21 .

When the display structure 23 is a liquid crystal display structure, it usually includes an active matrix substrate (or TFT array substrate) and a color filter substrate that are arranged oppositely. The liquid crystal is packaged between the active matrix substrate and the color filter substrate. layer; and a backlight module disposed on the side of the active matrix substrate away from the color filter substrate. When the display structure 23 is an organic light-emitting diode display structure, it usually includes an active matrix substrate (or TFT array substrate) and an organic light-emitting diode array formed on the active matrix substrate. The TFT switch controls the organic light-emitting diode to emit light or not to emit light according to the image data. When the display structure 23 is a micro inorganic light emitting diode display structure, it usually includes an active matrix substrate (or TFT array substrate) and a micro inorganic light emitting device disposed on the active matrix substrate. Diode array, the TFT switch on the active matrix substrate controls the micro-inorganic light-emitting diodes to emit or not emit light according to the image data.

Please refer to FIG. 2 . In this embodiment, the ultrasonic fingerprint recognition module 10 includes: a resonant electrode layer 11 and a piezoelectric layer 12 . The piezoelectric layer 12 has an opposite first surface 121 and a second surface 123. The piezoelectric layer 12 can be made of polyvinylidene fluoride (PVDF), lithium niobate (LiNbO3), lead zirconate titanate (PZT), etc. and can generate piezoelectricity. It is composed of one or a combination of several piezoelectric materials with effect, but is not limited to this. The piezoelectric layer 12 is used to transmit and receive ultrasonic signals in a time-sharing manner when the ultrasonic fingerprint recognition module 10 is working.

Please refer to FIG. 1 and FIG. 2 at the same time. The electronic device 1 also includes an ultrasonic driving circuit 40 . The resonant electrode layer 11 is stacked on the first surface 121. The resonant electrode layer 11 has a plurality of sub-electrodes 111 arranged at insulated intervals and corresponding to the touch area 202. Each sub-electrode 111 can be driven independently. The ultrasonic driving circuit 40 is coupled to the touch driving circuit 30 and the resonant electrode layer 11 . The ultrasonic driving circuit 40 is used to provide ultrasonic driving signals to one or a plurality of sub-electrodes 111 . The sub-electrodes 111 are used to be activated according to the touch signal carrying the information of the touch area 202 output by the touch driving circuit 30 to receive the driving signal. The ultrasonic driving circuit 40 can drive and activate one sub-electrode 111 individually, or can drive and activate a plurality of sub-electrodes 111 at the same time.

In this embodiment, the touch surface 201 has four touch areas 202 and the resonant electrode layer 11 has four sub-electrodes 111 for description, but it is not limited to this. In another modified embodiment, the ultrasonic fingerprint recognition module 10 is formed with 5×7 sub-electrodes 111, as shown in Figures 6a to 6c. At this time, the electronic device 1 can satisfy different fingerprint recognition modes. When a finger 3 touches a touch area 202, only one sub-electrode 111 corresponding to the touch area 202 will be driven; when a finger 3 touches multiple touch areas 202 at the same time, only these touch areas 202 The corresponding plurality of sub-electrodes 111 will be driven simultaneously; when multiple fingers 3 touch multiple touch areas 202 at the same time, only the plurality of sub-electrodes 111 corresponding to these touch areas 202 will be driven simultaneously.

In this embodiment, the material that makes up the resonant electrode layer 11 is silver. In other embodiments, the resonant electrode layer 11 can also be made of other conductive materials. Please continue to refer to FIG. 2 . A surface of the resonant electrode layer 11 away from the piezoelectric layer 12 is covered with a protective layer 17 . Part of the protective layer 17 covers the resonant electrode layer 11 , and the other part is filled in the intervals between the resonant electrode layers 11 . The material of the protective layer 17 may be an insulating material, such as insulating ink, but is not limited thereto.

Please continue to refer to FIG. 2 . The ultrasonic fingerprint recognition module 10 also includes a TFT array substrate 14 . The TFT array substrate 14 is disposed on the second surface 123 side. The TFT array substrate 14 may be a display module 20 (display The active matrix substrate of the structure 23) includes a display area (not shown) for displaying images, and the resonant electrode layer 11 and the piezoelectric layer 12 cover at least the entire display area of the active matrix substrate. area, at this time, the electronic device 1 can realize full-screen fingerprint recognition. The TFT array substrate 14 includes a plurality of thin film transistors (Thin Film Transistor, TFT) arranged in a matrix. The TFT array substrate 14 also includes a plurality of pixel circuits 141 and a plurality of receiving electrodes 143. A plurality of pixel circuits 141 are arranged in a matrix to form a pixel circuit array 142; a plurality of receiving electrodes 143 are arranged in a matrix to form a receiving electrode array 144. The receiving electrode array 144 is coupled to the piezoelectric layer 12. The material of the receiving electrode 143 may be a transparent metal oxide conductive material. In this embodiment, the receiving electrode 143 is made of indium tin oxide (ITO), but it is not limited to this.

The ultrasonic fingerprint recognition module 10 has the function of transmitting ultrasonic waves and receiving ultrasonic waves in a time-sharing manner. The resonant electrode layer 11 and the receiving electrode array 144 cooperate with the piezoelectric layer 12 to emit ultrasonic waves during the ultrasonic wave transmitting period. The resonant electrode layer 11 cooperates with the piezoelectric layer 12 to receive ultrasonic waves and convert them into electrical signals during the ultrasonic wave receiving period. The TFT array substrate 14 is used to couple out the ultrasonic waves. Describe electrical signals. The above-mentioned electrical signal is an electrical signal with fingerprint peak and valley characteristics.

Please continue to refer to Figure 2. The ultrasonic fingerprint recognition module 10 also includes an insulating flat layer 16. The flat layer 16 is insulated between the receiving electrode array 144 and the piezoelectric layer 12. The flat layer 16 is made of insulating materials such as resin, PET, and metal. made, but not limited to this.

Referring to Figures 3 and 4, the resonant electrode layer 11, the piezoelectric layer 12 and the TFT array substrate 14 are stacked. The ultrasonic fingerprint recognition module 10 also includes a fingerprint recognition chip 13 and a flexible circuit board 15 . The fingerprint recognition chip 13 is electrically connected to each sub-electrode 111 . One end of the flexible circuit board 15 is connected to the fingerprint recognition chip 13 , and the other end is connected to the TFT array substrate 14 to transmit the electrical signals coupled out of the TFT array substrate 14 during the ultrasonic wave reception period to the fingerprint recognition chip 13 . The fingerprint identification chip 13 and the ultrasonic driving circuit 40 can be integrated into an integrated circuit (IC).

When the finger 3 touches the touch surface 201 , the touch driving circuit 30 determines the touch area 202 touched by the finger 3 and outputs a touch signal carrying the information of the touch area 202 to the ultrasonic driving circuit 40 . During the ultrasonic emission period: the ultrasonic driving circuit 40 receives the touch signal from the touch driving circuit 30 and drives one or a plurality of sub-electrodes 111 corresponding to the touch area 202 of the touched film. Among them, the ultrasonic driving circuit 40 provides an alternating current with a frequency of 2 GHZ or above to drive one or a plurality of sub-electrodes 111 . After one or a plurality of sub-electrodes 111 are driven, they form a potential difference with the flat layer 16 above and below the piezoelectric layer 12, and the piezoelectric layer 12 generates ultrasonic waves due to the reverse piezoelectric effect. After the ultrasonic wave is transmitted to the finger 3, the ultrasonic wave may be reflected, absorbed, dispersed, or reflected back. Most of these ultrasonic waves are reflected back Piezoelectric layer 12 for detection. During the ultrasonic wave receiving period: when the piezoelectric layer 12 receives the reflected ultrasonic wave, it will be polarized and form an electrical signal on the first surface 121 . The second surface 123, the flat layer 16 and the receiving electrode array 144 form a coupling capacitor, which is used to couple the electrical signal to the pixel circuit array 142. The pixel circuit array 142 is used for screening processing and through flexible The circuit board 15 outputs the electrical signal to the fingerprint identification chip 13, and the fingerprint identification chip 13 finally identifies the fingerprint.

The receiving electrode array 144 is coupled to the piezoelectric layer 12. The resonant electrode layer 11 and the receiving electrode array 144 cooperate with the piezoelectric layer 12 to emit ultrasonic waves during the ultrasonic wave transmitting period. The resonant electrode layer 11 cooperates with the piezoelectric layer 12 to receive ultrasonic waves during the ultrasonic receiving period and convert them into electrical signal.

Referring to FIG. 5 , a control line 112 is connected to each sub-electrode 111 , and a plurality of pins 145 are provided on the TFT array substrate 14 . The other end of the control line 112 is electrically connected to the ultrasonic driving circuit 40 (not shown) on the pin 145, so that the ultrasonic driving circuit 40 can drive one or a plurality of sub-electrodes 111. Each control line 112 can be connected to any pin 145 according to actual conditions.

The ultrasonic fingerprint identification module 10 provided by this application can be installed in any electronic device 1 with a touch function to perform ultrasonic fingerprint identification. The ultrasonic fingerprint identification module 10 provided by this application does not need to drive the entire fingerprint identification process. The resonant electrode layer 11 only needs to drive one or a plurality of sub-electrodes 111 corresponding to the touch area 202 to complete the fingerprint recognition process, so that the electronic device 1 equipped with the ultrasonic fingerprint recognition module 10 has faster fingerprint recognition. The response speed and the effect of saving power.

An embodiment of the present application also provides an ultrasonic fingerprint identification method, which is applied to the above-mentioned electronic device 1 .

Please refer to Figure 7. The ultrasonic fingerprint identification method provided by the embodiment of the present application includes the following steps: Step S10, the touch drive circuit receives the touch operation and distinguishes one or multiple touched areas and outputs a touch signal; Step S20, Ultrasonic wave The driving circuit drives one or a plurality of sub-electrodes corresponding to the touch area according to the touch signal; step S30, the piezoelectric layer sends an ultrasonic signal to the finger, and receives the ultrasonic signal reflected from the surface of the finger back to the piezoelectric layer. The ultrasonic signal is converted into an electrical signal and output to the TFT array substrate; Step S40: The TFT array substrate screens the electrical signals and transmits the screened electrical signals to the fingerprint recognition chip; Step S50: The fingerprint recognition chip receives the screened electrical signals and processes them. The filtered electrical signals are subjected to fingerprint recognition calculations.

Since there are often noises in the received electrical signals with fingerprint characteristics, in this embodiment, by filtering the electrical signals, it is helpful to obtain the part of the electrical signals with less noise, and the filtered electrical signals can be used for subsequent The calculation process is conducive to improving the calculation accuracy.

Those of ordinary skill in the art should realize that the above embodiments are only used to illustrate the present invention and are not used to limit the present invention. As long as the above embodiments are appropriately made within the scope of the essential spirit of the present invention, Changes and variations are within the scope of the present invention.

10: Ultrasonic fingerprint recognition module

11: Resonance electrode layer

111: Sub-electrode

12: Piezoelectric layer

121: First surface

123: Second surface

14:TFT array substrate

16: Flat layer

17:Protective layer

141:Pixel circuit

142: Pixel circuit array

143: Receiving electrode

144: Receiving electrode array

Claims (9)

An electronic device, which is improved in that it includes: an ultrasonic fingerprint identification module. The ultrasonic fingerprint identification module includes: a piezoelectric layer having opposite first and second surfaces; a resonant electrode layer stacked on the On the first surface, the resonant electrode layer has a plurality of sub-electrodes arranged at insulating intervals. Each of the sub-electrodes can be independently driven and activated, and is used to receive a driving signal according to the touch position; the TFT array substrate and the insulating flat layer, are located on one side of the second surface. The TFT array substrate includes a pixel circuit array and a receiving electrode array. The pixel circuit array is located on the side of the receiving electrode array away from the resonant electrode layer. An insulating flat layer is disposed between the receiving electrode array and the piezoelectric layer. The resonant electrode layer and the receiving electrode array cooperate with the piezoelectric layer to emit ultrasonic waves during the ultrasonic wave emission period. The resonant electrode layer cooperates with The piezoelectric layer receives ultrasonic waves and converts them into electrical signals during the ultrasonic wave receiving period. The piezoelectric layer, the insulating flat layer and the receiving electrode array form a coupling capacitor, and the coupling capacitor is used to convert the electrical signals Coupled to the pixel circuit array, the pixel circuit array is used to screen the electrical signal and couple out the screened electrical signal; and a fingerprint recognition chip is electrically connected to each of the sub-electrodes, so The fingerprint recognition chip is used to receive the screened electrical signals and perform fingerprint recognition calculations on the screened electrical signals; a display module, the display module includes a touch sensing structure for realizing a touch function and a display structure for displaying images, the touch sensing structure includes a touch surface for receiving touch operations, the TFT array substrate is an active matrix substrate of the display structure, and the display structure is connected to the touch surface. The ultrasonic fingerprint recognition module shares the TFT array substrate, and the touch surface has a plurality of touch areas corresponding to a plurality of the sub-electrodes; a touch drive circuit is used when the touch surface is touched by a finger. , the touch drive circuit determines the touched touch area, and outputs a touch signal carrying the touch area information; and an ultrasonic drive circuit, coupled to the touch drive circuit and the sub-electrode, the ultrasonic wave The driving circuit is used to drive one or a plurality of the sub-electrodes according to the touch signal. The electronic device according to claim 1, wherein the ultrasonic fingerprint recognition module further includes a protective layer disposed on the resonant electrode layer. The electronic device according to claim 1, wherein the ultrasonic fingerprint recognition module further includes a flexible circuit board, one end of the flexible circuit board is connected to the fingerprint recognition chip, and the other end is connected to the TFT array substrate. The electronic device according to claim 1, wherein the ultrasonic fingerprint recognition module further includes a plurality of control lines, one end of each of the control lines is connected to one of the sub-electrodes, and the other end is electrically connected to the ultrasonic driving circuit. sexual connection. The electronic device according to claim 1, wherein the resonant electrode layer is made of silver. The electronic device according to claim 1, wherein the TFT array substrate includes a display area for displaying images, and the piezoelectric layer and the resonant electrode layer cover the display area. The electronic device according to claim 1, wherein the material of the receiving electrode array is a transparent metal oxide conductive material. The electronic device according to any one of claims 1 to 7, wherein the display structure is one of a liquid crystal display structure, an organic light-emitting diode display structure and a micro-inorganic light-emitting diode display structure. An ultrasonic fingerprint identification method, applied to the electronic device as described in any one of claims 1 to 8, the improvement includes the following steps: a touch drive circuit receives a touch operation and distinguishes one or multiple touch areas that are touched And output a touch signal; the ultrasonic driving circuit drives one or a plurality of sub-electrodes corresponding to the touch area according to the touch signal; the piezoelectric layer sends out the ultrasonic signal to the finger, and receives the reflected signal from the surface of the finger. The ultrasonic signal of the piezoelectric layer is converted into an electrical signal and output to the TFT array substrate; the TFT array substrate screens the electrical signal and transmits the screened electrical signal to the fingerprint recognition chip; the The fingerprint recognition chip receives the screened electrical signals and performs fingerprint recognition calculations on the screened electrical signals.

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