Fingerprint recognition circuit and electronic device

Abstract

The application discloses a kind of fingerprint identification circuit and electronic equipment, belong to electronic circuit technical field.Therein, fingerprint identification circuit includes: at least one pressure sensor, metal substrate, at least one acoustic wave fingerprint sensor and fingerprint control chip, wherein: for any pressure sensor, it is arranged in the metal substrate that is attached with the lower surface of the screen of electronic equipment, for detecting the pressure signal of the upper surface of screen;For any acoustic wave fingerprint sensor, it is attached in the side of metal substrate that is away from screen, for detecting the fingerprint signal of the upper surface of screen;Fingerprint control chip is connected with the output end of any acoustic wave fingerprint sensor fingerprint signal, the pressure signal output end of any pressure sensor respectively, for generating fingerprint image according to fingerprint signal, and determining pressure value according to pressure signal.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic circuits, and particularly relates to a fingerprint identification circuit and an electronic device. BACKGROUND

[0002] With the rapid development of science and technology, screen-under fingerprint identification has become a new direction of the development of fingerprint identification technology.

[0003] The current screen-under fingerprint identification scheme can only perform fingerprint identification, and has a single function. However, a scheme capable of realizing at least two functions is a point of attention in the design of an electronic device at present. Therefore, how to make the screen-under fingerprint identification scheme complete the function other than fingerprint identification and avoid the problem of a single function caused by the fact that the fingerprint identification scheme can only perform fingerprint identification has become a technical problem to be solved urgently. SUMMARY

[0004] The purpose of the embodiment of the application is to provide a fingerprint identification circuit and an electronic device, which can solve the problem of a single function caused by the fact that the current screen-under fingerprint identification scheme can only perform fingerprint identification.

[0005] In a first aspect, the embodiment of the application provides a fingerprint identification circuit, comprising at least one pressure sensor, a metal substrate, at least one acoustic wave fingerprint sensor and a fingerprint control chip, wherein:

[0006] For any pressure sensor, the pressure sensor is arranged in the metal substrate attached to the lower surface of the screen of an electronic device, and is used for detecting the pressure signal of the upper surface of the screen;

[0007] For any acoustic wave fingerprint sensor, the acoustic wave fingerprint sensor is attached to the side of the metal substrate away from the screen, and is used for detecting the fingerprint signal of the upper surface of the screen;

[0008] The fingerprint control chip is connected with the output end of any acoustic wave fingerprint sensor fingerprint signal, the pressure signal output end of any pressure sensor, and is used for generating a fingerprint image according to the fingerprint signal and determining a pressure value according to the pressure signal.

[0009] In a second aspect, the embodiment of the application provides an electronic device, which comprises the fingerprint identification circuit as described in the first aspect.

[0010] The embodiment of the present application provides a kind of fingerprint identification circuit, comprising: at least one pressure sensor, metal substrate, at least one acoustic wave fingerprint sensor and fingerprint control chip, wherein: for any the pressure sensor, it is arranged in the metal substrate that is attached with the lower surface of the screen of electronic equipment, for detecting the pressure signal of the upper surface of the screen;For any the acoustic wave fingerprint sensor, it is attached to the side of the metal substrate that is away from the screen, for detecting the fingerprint signal of the upper surface of the screen;The fingerprint control chip is connected with the output end of any the acoustic wave fingerprint sensor fingerprint signal, the pressure signal output end of any the pressure sensor respectively, for generating fingerprint image according to the fingerprint signal, and determining pressure value according to the pressure signal.The fingerprint identification circuit provided by the embodiment of the present application not only can realize fingerprint identification, but also realize pressure detection.This solves the problem of single function caused by the current under-screen fingerprint identification scheme only for fingerprint identification.In addition, the fingerprint identification circuit provided by the embodiment of the present application can also optimize the acoustic impedance matching of ultrasonic fingerprint sensor and screen, reduce the attenuation of acoustic wave signal, so that the acoustic wave fingerprint sensor can obtain acoustic wave signal with sufficient intensity. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a structure schematic of the fingerprint identification circuit provided by the embodiment of the present application Figure 1 ;

[0012] Figure 2a It is a structure schematic of the pressure sensor provided by the embodiment of the present application;

[0013] Figure 2b It is a working principle schematic of the pressure sensor provided by the embodiment of the present application;

[0014] Figure 3a It is a structure schematic of the ultrasonic wave fingerprint sensor provided by the embodiment of the present application;

[0015] Figure 3b It is a working principle schematic of the ultrasonic wave fingerprint sensor provided by the embodiment of the present application;

[0016] Figure 4 It is a structure schematic of the fingerprint identification circuit provided by the embodiment of the present application two;

[0017] Figure 5 It is a structure schematic of the fingerprint identification circuit provided by the embodiment of the present application three;

[0018] Figure 6 It is a structure schematic of the fingerprint identification circuit provided by the embodiment of the present application Figure 4 ;

[0019] Figure 7Fig. 1 is a distribution diagram of a pressure sensor and an acoustic wave fingerprint sensor provided by an embodiment of the present application Figure 1 ;

[0020] Figure 8 Fig. 2 is a second distribution diagram of a pressure sensor and an acoustic wave fingerprint sensor provided by an embodiment of the present application

[0021] Figure 9 Fig. 3 is a third distribution diagram of a pressure sensor and an acoustic wave fingerprint sensor provided by an embodiment of the present application DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art belong to the scope of protection of the present application.

[0023] The terms "first", "second", and the like in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally a category and do not limit the number of objects, for example, the first object can be one or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / ", generally indicates that the front and rear associated objects are in an "or" relationship.

[0024] The fingerprint identification circuit and electronic device provided by the embodiments of the present application will be described in detail below with reference to the drawings and specific embodiments and their application scenarios.

[0025] The present application provides a fingerprint identification circuit, as shown in Figure 1 The fingerprint identification circuit includes at least one pressure sensor 110, a metal substrate 120, at least one acoustic wave fingerprint sensor 130, and a fingerprint control chip 140, wherein:

[0026] For any pressure sensor 110, the pressure sensor is arranged in the metal substrate 120 which is attached to the lower surface of the screen of the electronic device, and is used to detect the pressure signal of the upper surface of the screen;

[0027] For any acoustic wave fingerprint sensor 130, the acoustic wave fingerprint sensor is attached to the side of the metal substrate 120 which is away from the screen, and is used to detect the fingerprint signal of the upper surface of the screen;

[0028] The fingerprint control chip 140 is connected with the fingerprint signal output end of any acoustic wave fingerprint sensor 130 and the output pressure signal output end of any pressure sensor 110, and is used for generating a fingerprint image according to a fingerprint signal and determining a pressure value according to a pressure signal.

[0029] In the embodiment of the present application, the pressure sensor 110 arranged in the metal substrate 120 can be etched or designed in the FPC (Flexible Printed Circuit), and the FPC is attached to the side of the metal substrate 120 facing the screen of the electronic device.

[0030] In the embodiment of the present application, the pressure sensor 110 can be a Wheatstone bridge 1101.

[0031] In one example, as shown in Figure 2a , the Wheatstone bridge 1101 is composed of a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a first power supply VDD.

[0032] The resistance values of the resistor R1, the resistor R2, the resistor R3 and the resistor R4 are usually the same, and the specific resistance values can be adjusted according to the actual design, which is not limited in the embodiment of the present application. In addition, terminals are drawn between the resistor R1 and the resistor R2 and between the resistor R3 and the resistor R4 as output ends of the pressure sensor 110 for outputting pressure signals.

[0033] Taking the pressure sensor 110 as the Wheatstone bridge 1101 as an example, the structure as shown in Figure 2a and Figure 2b is used to explain the working principle of the pressure sensor 110.

[0034] The pressure sensor 110 is attached to the lower surface of the display panel and the screen. When the finger presses the screen, the screen and the display panel are deformed, and the pressure sensor 110 is deformed. According to Ohm's law and the voltage division formula, Vp1=VDD*R2 / (R1+R2), Vp2=VDD*R4 / (R3+R4). When the Wheatstone bridge 1101 is deformed by pressure, the resistance value of at least one of the resistor R1, the resistor R2, the resistor R3 and the resistor R4 changes, thereby generating a voltage difference; the pressure signal can be the voltage Vp1 and the voltage Vp2, or the pressure signal is the difference between the two voltages: S=Vp1-Vp2. In this way, the detection of the voltage Vp1 and the voltage Vp2 can realize the detection of the pressure value.

[0035] It should be noted that Figure 2b in the above embodiment, the display panel is taken as an OLED panel and the screen is taken as a glass cover plate Glass as an example.

[0036] In the embodiments of the present application, the acoustic wave fingerprint sensor 130 is a sensor for collecting a fingerprint signal by emitting and receiving acoustic waves. For example, the acoustic wave fingerprint sensor 130 can be an ultrasonic fingerprint sensor or other types of acoustic wave sensor.

[0037] Taking the ultrasonic sensor as an example, the working principle of the acoustic wave sensor is illustrated as shown in the structures of FIGS. 8A and 8B. Figure 3a and Figure 3b

[0038] The piezoelectric effect and the inverse piezoelectric effect of the piezoelectric material are utilized to realize the mutual conversion between the electric signal and the acoustic wave signal.

[0039] Specifically, in the ultrasonic wave transmitting TX stage: the switch connects the piezoelectric material to the ground, and the high-voltage AC power supply provides a high-voltage AC signal to both ends of the piezoelectric material, and the piezoelectric material converts the electric signal into an ultrasonic wave signal through the piezoelectric effect. The ultrasonic wave penetrates the metal substrate 120 to be transmitted to the display panel OLED Panel and the upper surface of the screen in turn, and is absorbed and reflected at the contact surface of the finger and the screen.

[0040] In the ultrasonic wave receiving RX stage: the switch connects the piezoelectric material to the output end of the acoustic wave fingerprint sensor 130. Due to the difference in acoustic impedance between air and the skin of the finger, the reflection intensity of the ultrasonic wave at the contact surface of the screen and the fingerprint wave crest and trough is different. The reflected ultrasonic wave signal is converted into an electric signal with different intensities through the inverse piezoelectric effect of the piezoelectric material, and the electric signal is taken as the fingerprint signal.

[0041] Among them, Figure 3b The screen is taken as a glass cover plate Glass as an example.

[0042] In the embodiments of the present application, the metal substrate 120 is used to carry any pressure sensor 110. The metal substrate 120 can be a copper foil or a flexible circuit board.

[0043] Of course, the metal substrate 120 can also be other metal substrates, such as aluminum, nickel or metal composites.

[0044] In the case that an external force is applied to the screen, the application position of the external force on the screen is projected at any position of the metal substrate 120, and even if there is no pressure sensor 110 at the any position, the metal substrate 120 can still transmit the external force to the pressure sensor 110. In this way, it is not necessary to arrange dense pressure sensors 110 on the metal substrate 120. That is to say, the number of pressure sensors 110 can be reduced, thereby reducing the hardware cost of the fingerprint identification circuit provided by the embodiments of the present application.

[0045] ​In addition, the metal substrate 120 can make the ultrasonic fingerprint sensor 130 indirectly better adhere to the screen, so as to improve the acoustic energy transmission between the ultrasonic fingerprint sensor 130 and the screen, and further optimize the acoustic impedance matching between the ultrasonic fingerprint sensor and the screen, reduce the attenuation of the acoustic wave signal, so that the ultrasonic fingerprint sensor 130 can obtain an acoustic wave signal with sufficient intensity.

[0046] In an embodiment of the present application, as shown in Figure 4 The two sides of the metal substrate 120 are filled with pressure sensitive adhesive (PSA) 150.

[0047] In the present embodiment, the pressure sensitive adhesive 150 can make the metal substrate 120 completely adhere to the screen and the ultrasonic fingerprint sensor 130. This can further optimize the acoustic impedance matching between the ultrasonic fingerprint sensor 130 and the screen.

[0048] In an embodiment of the present application, in the case of the metal substrate 120 being a copper foil, the total thickness of the copper foil and the pressure sensitive adhesive on both sides is less than or equal to 50 mm. This can reduce the attenuation of the fingerprint signal.

[0049] In addition, the metal substrate 120 can cover any ultrasonic fingerprint sensor 130, of course, it can also cover only part of the ultrasonic fingerprint sensor 130. The present application does not limit this.

[0050] It should be noted that in the case of the metal substrate 120 covering any ultrasonic fingerprint sensor 130, the acoustic impedance matching between all ultrasonic fingerprint sensors 130 and the screen can be optimized.

[0051] In an embodiment of the present application, as shown in Figure 4 The structure shown in the figure, a display panel 160 such as an OLED panel is generally arranged on the side of the metal substrate 120 facing the screen 170. The screen 170 is realized by a glass cover plate Glass.

[0052] It should be noted that in actual design, the screen 170, the pressure sensitive adhesive 150, the metal substrate 120, and the ultrasonic fingerprint sensor 130 are closely adhered. Figure 4 The separation in the figure is only for the purpose of clearly showing the structure of the fingerprint identification circuit.

[0053] It should be noted that Figure 4 The metal substrate 120 is a copper foil, the display panel 160 is an OLED panel, and the screen 170 is a glass cover plate Glass in the figure.

[0054] In the embodiment of the present application, for any pressure sensor 110, the working principle of the pressure sensing control chip processing the pressure signal of the pressure sensor 110 is: the pressure signal output by any pressure sensor 110 is amplified and sampled by an ADC (Analog to Digital Converter), and then the corresponding pressure value is obtained.

[0055] At the same time, for any acoustic fingerprint sensor 130, the working principle of the fingerprint control chip 140 processing the acoustic signal output by the acoustic fingerprint sensor 130 is: the fingerprint signal collected by any acoustic fingerprint sensor 130 is amplified and sampled by an ADC, and then the corresponding fingerprint image is obtained.

[0056] Based on the above, it can be seen that the working principles of the fingerprint control chip 140 and the pressure sensing control chip are the same. Therefore, in the embodiment of the present application, the fingerprint control chip 140 can not only process the fingerprint signal to obtain the corresponding fingerprint image, but also process the pressure signal to obtain the corresponding pressure value.

[0057] Based on the above, it can be seen that the fingerprint recognition circuit provided in the embodiment of the present application not only realizes fingerprint recognition, but also realizes pressure detection. This solves the problem of single function caused by the fact that the current under-screen fingerprint recognition scheme can only perform fingerprint recognition. In addition, the fingerprint recognition circuit provided in the embodiment of the present application can also optimize the acoustic impedance matching between the ultrasonic fingerprint sensor 130 and the screen, and reduce the attenuation of the acoustic signal, so that the acoustic fingerprint sensor 130 can obtain acoustic signals with sufficient intensity.

[0058] The embodiment of the present application provides a fingerprint recognition circuit, which comprises at least one pressure sensor, a metal substrate, at least one acoustic fingerprint sensor, and a fingerprint control chip. For any pressure sensor, the pressure sensor is arranged in the metal substrate which is attached to the lower surface of the screen of an electronic device, and is used to detect the pressure signal of the upper surface of the screen. For any acoustic fingerprint sensor, the acoustic fingerprint sensor is attached to the side of the metal substrate which is away from the screen, and is used to detect the fingerprint signal of the upper surface of the screen. The fingerprint control chip is connected to the output end of any acoustic fingerprint sensor and the pressure signal output end of any pressure sensor, and is used to generate a fingerprint image according to the fingerprint signal and determine a pressure value according to the pressure signal. The fingerprint recognition circuit provided in the embodiment of the present application not only realizes fingerprint recognition, but also realizes pressure detection. This solves the problem of single function caused by the fact that the current under-screen fingerprint recognition scheme can only perform fingerprint recognition. In addition, the fingerprint recognition circuit provided in the embodiment of the present application can also optimize the acoustic impedance matching between the ultrasonic fingerprint sensor and the screen, and reduce the attenuation of the acoustic signal, so that the acoustic fingerprint sensor can obtain acoustic signals with sufficient intensity.

[0059] In an embodiment of the present application, as shown in Figure 5 The fingerprint control chip 140 includes: a first control unit 1401 and a second control unit 1402 corresponding to each pressure sensor 110, and a third control unit 1403 corresponding to each acoustic wave fingerprint sensor 130.

[0060] Any first control unit is connected to the output end of the first pressure signal output by the pressure sensor, for determining the first pressure value according to the first pressure signal.

[0061] Any second control unit is connected to the output end of the second pressure signal output by the pressure sensor, for determining the second pressure value according to the second pressure signal.

[0062] Any third control unit 1403 is connected to the fingerprint signal output end of the acoustic wave fingerprint sensor 130, for generating a fingerprint image according to the fingerprint signal.

[0063] Wherein, the pressure signal includes the first pressure signal and the second pressure signal, and the pressure value includes the first pressure value and the second pressure value.

[0064] It should be noted that, Figure 5 is an example of taking the pressure sensor 110 as a Wheatstone bridge, the fingerprint control chip 140 including one first control unit 1401 and one second control unit 1402, and two third control units 1403. In addition, it can be understood that the fingerprint control chip 140 also includes an interface for outputting the pressure value and the fingerprint image.

[0065] In an embodiment of the present application, the first pressure signal is the voltage Vp2 output by the Wheatstone bridge of the pressure sensor 110, and the second pressure signal is the voltage Vp1 output by the Wheatstone bridge of the pressure sensor 110. Alternatively, the first pressure signal is the voltage Vp1 output by the Wheatstone bridge of the pressure sensor 110, and the second pressure signal is the voltage Vp2 output by the Wheatstone bridge of the pressure sensor 110.

[0066] And for any first control unit 1401, it includes an operational amplifier, an ADC, and a compensation capacitor C. Wherein: the non-inverting input end of the operational amplifier is used to access the reference voltage Vref, the inverting input end of the operational amplifier is used to connect the first pressure signal output end of the pressure sensor 110, and the output end of the operational amplifier is connected to the input end of the ADC. The output end of the ADC is connected to the interface. The compensation capacitor C is connected between the inverting input and output ends of the operational amplifier.

[0067] For any second control unit 1402, the difference from the above-mentioned first control unit 1401 is only that the inverting input of the operational amplifier in the second control unit 1402 is used to connect the output end of the second pressure signal of the pressure sensor 110.

[0068] For any third control unit 1403, the difference from the above-mentioned first control unit 1401 is that the inverting input terminal of the operational amplifier in the third control unit 1403 is used for connecting the output terminal of the acoustic wave fingerprint sensor 130.

[0069] In the embodiment of the present application, a fingerprint control chip 140 with simple structure is provided.

[0070] In an embodiment of the present application, the fingerprint identification circuit further comprises a first power supply, a second power supply and a first processing unit, wherein:

[0071] The first power supply is connected with the power supply terminal of each pressure sensor 110 respectively;

[0072] The second power supply is connected with the power supply terminal of each acoustic wave fingerprint sensor 130 respectively;

[0073] The first processing unit is connected with the control terminal of the first power supply and the control terminal of the second power supply respectively, and is used for controlling the first power supply to be turned off in the first working state and controlling the second power supply to be turned off in the second working state.

[0074] In the embodiment of the present application, the first working state is a working state in which fingerprint identification is needed, for example, a working state in which unlocking is needed. The second working state is a working state in which pressure detection is needed, for example, a working state in which a game is needed.

[0075] The first power supply is connected with the power supply terminal of each pressure sensor respectively, and is used for providing working power supply for each pressure sensor. The second power supply is connected with the power supply terminal of each acoustic wave fingerprint sensor respectively, and is used for providing working power supply for each acoustic wave fingerprint sensor.

[0076] In the embodiment of the present application, the first processing unit controls the first power supply to be turned off in the first working state, i.e., in the working state in which fingerprint identification is needed. At this time, the working power supply of the pressure sensor 110 is turned off, and the pressure sensor 110 cannot work, so that no pressure signal is fed back to the fingerprint control chip 140. In this way, the fingerprint control chip 140 does not need to perform pressure detection, and the energy consumption of the fingerprint control chip 140 can be reduced. Meanwhile, the function of the pressure sensor 110 does not affect the function of the acoustic wave fingerprint sensor 130, and the pressure sensor 110 and the acoustic wave fingerprint sensor 130 can be compatible in position. On this basis, the area under the screen can also be saved, and the layout of the device under the screen is facilitated.

[0077] Correspondingly, the first processing unit controls the second power supply to be turned off in the second working state, i.e., in the working state in which pressure detection is required. At this time, the working power supply of the acoustic fingerprint sensor 130 is turned off, and the acoustic fingerprint sensor 130 cannot work, so that no fingerprint signal is fed back to the fingerprint control chip 140. In this way, the fingerprint control chip 140 does not need to perform fingerprint identification, and the energy consumption of the fingerprint control chip 140 can be reduced. At the same time, the function of the acoustic fingerprint sensor 130 does not affect the function of the pressure sensor 110, and the pressure sensor 110 and the acoustic fingerprint sensor 130 can be compatible in position. On this basis, the under-screen area can also be saved, and the layout of the under-screen device is facilitated.

[0078] In an embodiment of the present application, as shown in Figure 6 The fingerprint identification circuit provided by the embodiment of the present application includes N pressure sensors 110, N first acoustic sensors 1301 and N second acoustic sensors 1302 in the acoustic fingerprint sensor 130, and the fingerprint control chip 140 includes N first switches 1404, N second switches 1405, a fourth control unit 1406 corresponding to the first acoustic sensor 1301, a fifth control unit 1407 corresponding to the second acoustic sensor 1302, and a second processing unit. Wherein:

[0079] The first pressure signal output end of any pressure sensor 110 is connected with the first end of the first switch 1404, and the second pressure signal output end is connected with the first end of the second switch 1405;

[0080] The second end of any first switch 1404 is connected with the output end of the first acoustic fingerprint sensor 1301, and the third end is connected with the fourth control unit 1406;

[0081] The second end of any second switch 1405 is connected with the output end of the second acoustic fingerprint sensor 1302, and the third end is connected with the fifth control unit 1407;

[0082] The second processing unit is configured to control the second end and the third end of any first switch 1404 to be connected, and the second end and the third end of any second switch 1405 to be connected in the first working state, and control the first end and the third end of any first switch 1404 to be connected, and the first end and the third end of any second switch 1405 to be connected in the second working state;

[0083] Any fourth control unit 1406 is configured to generate a fingerprint image according to the fingerprint signal output by the first acoustic fingerprint sensor 1301 in the first working state, and determine a first pressure value according to the first pressure signal in the second working state;

[0084] Any fifth control unit 1407 is configured to generate a fingerprint image according to the fingerprint signal output by the second acoustic fingerprint sensor 1302 in the first working state, and determine the second pressure value according to the second pressure signal in the second working state.

[0085] The pressure signal includes the first pressure signal and the second pressure signal, the pressure value includes the first pressure value and the second pressure value, and N is a positive integer greater than 0.

[0086] It should be noted that, Figure 6 The first voltage signal output end is the output end of the output voltage Vp2, the second voltage signal output end is the output end of the output voltage Vp1, and the pressure sensor 110 is a Wheatstone bridge. In addition, Figure 6 The second processing unit is not output in the embodiment.

[0087] In the embodiment, the switch connected to the first pressure signal output end of the pressure sensor 110 is referred to as the first switch 1404, and the switch connected to the second output end of the pressure sensor 110 is referred to as the second switch 1405.

[0088] The acoustic fingerprint sensor 130 used for connection with the first switch 1404 is referred to as the first acoustic fingerprint sensor 1301, and the acoustic fingerprint sensor 130 used for connection with the second switch 1405 is referred to as the second acoustic fingerprint sensor 1302.

[0089] The control unit for processing the fingerprint signal output by the first acoustic fingerprint sensor 1301 is referred to as the fourth control unit 1406, and the control unit for processing the fingerprint signal output by the second acoustic fingerprint sensor 1302 is referred to as the fifth control unit 1407.

[0090] As shown in Figure 6 The structure of the fourth control unit 1406 and the fifth control unit 1407 can be as shown in the structure of the first control unit 1401 in Figure 5 The detailed description is omitted here.

[0091] In the embodiment, the second processing unit is configured to switch the switch state of the first switch 1404 and the second switch 1405. Specifically, the second processing unit is configured to control the second end of any first switch 1404 to be connected to the third end, and the second end of any second switch 1405 to be connected to the third end in the first working state. In this way, the fourth control unit 1406 is connected to the output end of the fingerprint signal output by the first acoustic fingerprint sensor 1301, and generates a fingerprint image according to the fingerprint signal. At the same time, the fifth control unit 1406 is connected to the output end of the fingerprint signal output by the second acoustic fingerprint sensor 1302.

[0092] Correspondingly, the second processing unit is configured to, in the second working state, control the first end of any first switch 1404 to be connected to the third end, and the first end of any second switch 1405 to be connected to the third end. In this way, the fourth control unit 1406 is connected to the output end of the first pressure signal of the pressure sensor 110, and generates a first pressure value according to the first pressure signal. Meanwhile, the fifth control unit 1407 is connected to the output end of the second pressure signal of the pressure sensor 110, and generates a second pressure value according to the second pressure signal.

[0093] In the embodiment of the present application, the first switch and the second switch can realize multiplexing of the pressure sensor and the acoustic wave fingerprint sensor to the fourth control unit and the fifth control unit. In this way, the number of control units in the fingerprint control chip can be greatly reduced, and the design cost of the fingerprint control chip is reduced.

[0094] In one embodiment of the present application, as shown in Figure 7 The coverage of the metal substrate 120 can be smaller than the coverage of the acoustic wave fingerprint sensor 130.

[0095] In one embodiment of the present application, as shown in Figure 8 The metal substrate 120 includes a first part 1201 and a second part 1202. The first part 1201 covers any acoustic wave fingerprint sensor 130, and the second part 1202 is provided with any pressure sensor 110.

[0096] Through the arrangement of the acoustic wave fingerprint sensor 130 and the pressure sensor 110 shown in the embodiment, the projection of the pressure sensor 110 and the projection of the acoustic wave fingerprint sensor 130 can be realized not to overlap, which can reduce the mutual influence between the pressure sensor 110 and the acoustic wave fingerprint sensor 130, and further improve the accuracy of the pressure sensor 110 and the acoustic wave fingerprint sensor 130.

[0097] In addition, since the metal substrate 120 covers all the acoustic wave fingerprint sensors 130, the acoustic impedance matching of all the ultrasonic fingerprint sensors 130 and the screen can be optimized.

[0098] In one embodiment of the present application, as shown in Figure 9 The pressure sensor 110 is at least two, and at least one pressure sensor 110 includes at least one first pressure sensor 1101 and at least one second pressure sensor 1102, wherein:

[0099] The metal substrate 120 is provided with at least one first pressure sensor 1101;

[0100] For any second pressure sensor 1102, it is arranged on the area of the lower surface of the screen except the metal substrate 120.

[0101] In the embodiments of the present application, the position of the pressure sensor 110 can be located at various positions of the lower surface of the entire screen. In this way, full-screen pressure detection of the electronic device can be realized through the pressure sensor 110.

[0102] The embodiments of the present application also provide an electronic device, which is the fingerprint identification circuit provided in any of the above embodiments.

[0103] For example, the electronic device can be a mobile phone, a tablet computer, a notebook computer, a palm computer, a vehicle-mounted electronic device, a Mobile Internet Device (MID), an augmented reality (AR) / virtual reality (VR) device, a robot, a wearable device, an ultra-mobile personal computer (UMPC), a netbook, or a personal digital assistant (PDA), etc., and can also be a teller machine or a self-service machine, etc.

[0104] The embodiments of the present application are described above in combination with the accompanying drawings, but the present application is not limited to the above-described specific embodiments, and the above-described specific embodiments are merely illustrative rather than limiting, and those of ordinary skill in the art can make many forms under the inspiration of the present application without departing from the scope of the present application and the scope protected by the claims.

Claims

1. A fingerprint recognition circuit, characterized by, The application relates to a fingerprint identification circuit, which comprises at least one pressure sensor, a metal substrate, at least one acoustic wave fingerprint sensor and a fingerprint control chip, wherein: for any pressure sensor, a pressure signal of an upper surface of a screen of an electronic device is detected in the metal substrate which is attached to a lower surface of the screen; for any acoustic wave fingerprint sensor, a fingerprint signal of the upper surface of the screen is detected on a side of the metal substrate which is away from the screen; the fingerprint control chip is connected with an output end of any acoustic wave fingerprint sensor and a pressure signal output end of any pressure sensor respectively, and is used for generating a fingerprint image according to the fingerprint signal and determining a pressure value according to the pressure signal; the fingerprint control chip comprises a first control unit and a second control unit which correspond to the pressure sensor one by one, and a third control unit which corresponds to the acoustic wave fingerprint sensor one by one; any first control unit is connected with a first pressure signal output end of the pressure sensor, and is used for determining a first pressure value according to the first pressure signal; any second control unit is connected with a second pressure signal output end of the pressure sensor, and is used for determining a second pressure value according to the second pressure signal; any third control unit is connected with a fingerprint signal output end of the acoustic wave fingerprint sensor, and is used for generating a fingerprint image according to the fingerprint signal; the pressure signal comprises the first pressure signal and the second pressure signal, and the pressure value comprises the first pressure value and the second pressure value. The metal substrate is a copper foil or a flexible circuit board. Both sides of the metal substrate are filled with pressure-sensitive adhesive. The fingerprint identification circuit further comprises a first power supply, a second power supply and a first processing unit, wherein: the first power supply is connected with a power supply end of each pressure sensor respectively; the second power supply is connected with a power supply end of each acoustic wave fingerprint sensor respectively; the first processing unit is connected with a control end of the first power supply and a control end of the second power supply respectively, and is used for controlling the first power supply to be closed in a first working state and controlling the second power supply to be closed in a second working state. The pressure sensor is N, the acoustic wave fingerprint sensor comprises N first acoustic wave sensors and N second acoustic wave sensors, the fingerprint control chip comprises N first switches, N second switches, a fourth control unit which corresponds to the first acoustic wave sensor one by one, a fifth control unit which corresponds to the second acoustic wave sensor one by one and a second processing unit, wherein: a first pressure signal output end of any pressure sensor is connected with a first end of the first switch, and a second pressure signal output end is connected with a first end of the second switch; a second end of any first switch is connected with an output end of the first acoustic wave fingerprint sensor, and a third end is connected with the fourth control unit; a second end of any second switch is connected with an output end of the second acoustic wave fingerprint sensor, and a third end is connected with the fifth control unit. ​ ​ ​ ​ ​ 2. The circuit of claim 1, wherein, ​ 3. The circuit of claim 1 or 2, characterized in that, ​ 4. The circuit of claim 1, wherein, ​ ​ ​ ​ 5. The circuit of claim 1, wherein, ​ ​ ​ ​ The second processing unit is configured to control the second end of any of the first switches to be connected to the third end and the second end of any of the second switches to be connected to the third end in the first working state, and control the first end of any of the first switches to be connected to the third end and the first end of any of the second switches to be connected to the third end in the second working state. Any of the fourth control units is configured to generate a fingerprint image according to the fingerprint signal output by the first acoustic fingerprint sensor in the first working state, and determine a first pressure value according to the first pressure signal in the second working state. Any of the fifth control units is configured to generate a fingerprint image according to the fingerprint signal output by the second acoustic fingerprint sensor in the first working state, and determine a second pressure value according to the second pressure signal in the second working state. The pressure signal includes the first pressure signal and the second pressure signal, the pressure value includes the first pressure value and the second pressure value, and N is a positive integer greater than 0.

6. The circuit of claim 1, wherein, The metal substrate includes a first part and a second part, the first part covers any of the acoustic fingerprint sensors, and the second part is provided with any of the pressure sensors.

7. The circuit of claim 1, wherein, The pressure sensor is at least two, the at least one pressure sensor includes at least one first pressure sensor and at least one second pressure sensor, wherein: The metal substrate is provided with the at least one first pressure sensor; For any of the second pressure sensor, it is arranged in the area of the lower surface of the screen except the metal substrate.

8. The circuit of claim 1, wherein, The acoustic sensor is an ultrasonic sensor, and the pressure sensor is a Wheatstone bridge.

9. An electronic device, comprising: The electronic device includes the fingerprint identification circuit as claimed in any of claims 1-8.

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