WO2022141117A1 - Fingerprint recognition device, display screen module, and electronic apparatus - Google Patents

Abstract

A fingerprint recognition device (300), a display screen module, and an electronic apparatus. The fingerprint recognition device (300) comprises: an ultrasonic generating device (310), an ultrasonic receiving device (320), and a signal processing module. The ultrasonic generating device (310) comprises a light source (311) and a light absorbing component (312). The light absorbing component (312) and the ultrasonic receiving device (320) are attached to the bottom of a display screen. The light source (311) is disposed on the side of the light absorbing component (312) away from the display screen. The light source (311) is configured to generate pulsed light. The light absorbing component (312) is configured to absorb the pulsed light and to generate an ultrasonic signal. The ultrasonic receiving device (320) receives an echo signal of the ultrasonic signal returned by a finger on the fingerprint detection region of the display screen, and converts the echo signal into a fingerprint electrical signal. The signal processing module is connected to the ultrasonic receiving device (320), and is configured to receive the fingerprint electrical signal and to generate a fingerprint image according to the fingerprint electrical signal. Thus, ultrasonic-based under-screen fingerprint recognition is implemented, and fingerprint recognition precision is improved on the basis of the strong penetrability and high sensitivity of ultrasound.

Description

Fingerprint identification devices, display modules and electronic equipment technical field

The present application relates to the technical field of fingerprint identification, and in particular, to a fingerprint identification device, a display screen module and an electronic device.

Background technique

Fingerprint recognition has become a function that most mobile terminals such as mobile phones and tablet computers are equipped with. As smartphones enter the era of full-screen display, the screen-to-body ratio of mobile phones is getting larger and larger, and under-screen fingerprint recognition technology has become a trend.

At present, the under-screen optical fingerprint recognition technology applied to the organic light-emitting diode (Organic Light-Emitting Diode, OLED) screen has entered the commercial era. The mobile terminal using the OLED screen uses the self-luminous display unit as the light source to illuminate the screen. The light emitted by the self-luminous display unit in the fingerprint detection area of the OLED screen forms a light spot and irradiates the finger above the screen to form the fingerprint detection light, and the fingerprint detection light returns. After passing through the OLED screen, it is received by the optical fingerprint sensor below the OLED screen, and the fingerprint image is collected through the optical fingerprint sensor to further realize fingerprint recognition.

However, as the light transmittance of the OLED screen is getting lower and lower, the signal of the fingerprint detection light passing through the OLED screen is getting weaker and weaker, which causes the difficulty of the under-screen optical fingerprint identification technology and makes the identification accuracy of the under-screen optical fingerprint identification technology relatively high. low, unable to meet user needs.

SUMMARY OF THE INVENTION

The present application provides a fingerprint identification device, a display module and electronic equipment, and proposes an ultrasonic-based under-screen fingerprint identification device, which utilizes the strong penetration ability and high sensitivity of ultrasound to improve the accuracy of fingerprint identification.

In a first aspect, an embodiment of the present application provides a fingerprint identification device, including:

An ultrasonic generating device, an ultrasonic receiving device and a signal processing module, the ultrasonic generating device includes a light source and a light absorbing component, the light absorbing component and the ultrasonic receiving device are used to be attached to the bottom of the display screen, and the light source is arranged on the light absorbing component The side of the component away from the display screen; wherein, the light source is used to generate pulsed light; the light absorption component is used to absorb the pulsed light and generate an ultrasonic signal; the ultrasonic receiving device is used to receive the display the echo signal of the ultrasonic signal returned by the finger above the fingerprint detection area of the screen, and convert the echo signal into a fingerprint electrical signal; the signal processing module is connected to the ultrasonic receiving device for receiving the fingerprint electrical signal, and generate a fingerprint image according to the fingerprint electrical signal.

In the embodiment of the present application, an ultrasonic signal is generated based on the photoacoustic effect by an ultrasonic generating device, and an echo signal of the ultrasonic signal returned by the finger on the upper part of the screen is received by the ultrasonic receiving device, and then converted into an electrical fingerprint signal, and the signal processing module is used to detect the echo signal. The fingerprint electrical signal is processed to generate a fingerprint image, which realizes the identification of the user's fingerprint based on ultrasound, with high identification accuracy, and the fingerprint identification device has low design complexity, low cost, and is easy to implement.

In a possible implementation manner, the ultrasonic receiving device is a two-dimensional ultrasonic receiver array, and the two-dimensional ultrasonic receiver array is composed of a first preset number of ultrasonic receivers.

The embodiment of the present application uses a two-dimensional ultrasonic receiver array to receive and convert ultrasonic signals. Compared with a single ultrasonic transducer, the absorption rate of ultrasonic signals is improved, so that the converted fingerprint signals have higher strength, which is beneficial to Improve image quality and fingerprint recognition accuracy.

In a possible implementation manner, the ultrasonic receiver is provided with a first electrode and a second electrode, and the first electrode and the second electrode are respectively provided on two sides of the piezoelectric material of the ultrasonic receiver. side.

The embodiment of the present application uses a two-dimensional ultrasonic receiver array to collect echo signals of ultrasonic signals, and the routing of each ultrasonic receiver in the two-dimensional ultrasonic receiver array is simple, which reduces the design cost and complexity of the device.

In a possible implementation manner, the piezoelectric material of the ultrasonic receiver includes AlN aluminum nitride material, modified aluminum nitride material, PVDF polyvinylidene fluoride material or lead zirconate titanate thin film material.

By selecting piezoelectric materials with higher piezoelectric coefficients in the embodiments of the present application, the sensitivity of the ultrasonic receiver is improved, thereby improving the accuracy of fingerprint identification.

In a possible implementation manner, the ultrasonic generating device includes at least two groups of the light sources and light absorbing components, and the ultrasonic receiving device includes at least two groups of the two-dimensional ultrasonic receiver arrays, wherein each group of the light sources The and light absorbing components correspond to a corresponding group of the two-dimensional ultrasonic receiver arrays, and different groups of the two-dimensional ultrasonic receiver arrays correspond to different fingerprint detection areas.

The embodiment of the present application provides an expandable ultrasonic generating device and an ultrasonic receiving device, so that the area available for fingerprint detection on the display screen is larger, and the convenience of fingerprint identification is improved. It is also possible to expand multiple groups of ultrasonic generating devices and ultrasonic receiving devices to form distributed receiving fingerprints in multiple sub-regions, thereby reducing the area of the ultrasonic receiver array of each group of ultrasonic receiving devices and further reducing costs.

In a possible implementation manner, the two-dimensional ultrasound receiver array is in the shape of a square, and the length of the square is at least 9 mm and the width is at least 4 mm.

In the embodiment of the present application, a square two-dimensional ultrasonic receiver array is arranged, and the square structure is favorable for splicing and coupling, and improves the coupling reliability of the two-dimensional ultrasonic receiver. By limiting the size of the two-dimensional ultrasonic receiver, it can meet the needs of the fingerprint recognition scene, and ensure that the two-dimensional ultrasonic receiver can receive enough ultrasonic signals for fingerprint imaging and identification, and improve the effectiveness of fingerprint identification.

In a possible implementation manner, the ultrasonic generating devices are respectively provided on both sides of the ultrasonic receiving device.

In the embodiment of the present application, by setting up multiple sets of ultrasonic generating devices, the contact area between the ultrasonic generating device and the ultrasonic receiving device is increased, so that more ultrasonic signals are absorbed by the ultrasonic generating device, thereby improving the quality of ultrasonic imaging and the accuracy of fingerprint identification.

In a possible embodiment, the light absorbing member includes a first part and a second part, the first part is located on one side of the ultrasonic receiving device, and the second part is located on the other side of the ultrasonic receiving device; The light sources are respectively disposed on surfaces of the first part and the second part opposite to the display screen.

In the embodiment of the present application, the ultrasonic generating devices are arranged on both sides of the ultrasonic receiving device, so that the intensity of the generated ultrasonic signal is improved, and the precision of fingerprint identification is improved.

In a possible implementation manner, the ultrasonic receiving device is elongated, and the ultrasonic generating device is disposed on two sides corresponding to two long sides of the ultrasonic receiving device.

In the embodiment of the present application, by arranging a long ultrasonic receiving device, it is more conducive to the coupling of the ultrasonic receiving device, and the reliability of the coupling is improved; meanwhile, the ultrasonic generating device is arranged on both sides of the long side of the ultrasonic receiving device, which can reduce the cost. At the same time, the contact area of the two is made as large as possible, thereby improving the absorption rate of the ultrasonic signal by the ultrasonic receiving device, thereby improving the imaging quality.

In a possible implementation manner, the light absorbing member is in the shape of a wedge or a strip.

In the embodiment of the present application, the light-absorbing component is attached under the display screen in an inverted wedge shape, so that the ultrasonic signal can be hit on the display screen at a certain angle and in an inclined manner, thereby improving the intensity of the echo signal and improving the accuracy of fingerprint recognition. .

In a possible implementation manner, the light absorbing member includes an inclined surface for coupling with the light source, a connecting surface for coupling with the display screen, and a vertical surface connected between the inclined surface and the connecting surface The inclined surface and the connecting surface form a preset angle, and the preset angle is an acute angle.

In the embodiment of the present application, the light-absorbing component including the inclined plane is used to realize the oblique incidence of the ultrasonic signal to the display screen, so that part of the ultrasonic signal is reflected, and part of the ultrasonic signal is transmitted to the upper part of the display screen and returned to the ultrasonic receiving device through the finger. Adding part of the transmitted ultrasonic signals improves the intensity of the ultrasonic signals absorbed by the ultrasonic receiving device, and improves the imaging quality and the fingerprint identification accuracy.

In a possible implementation manner, the light emitting surface of the light source is parallel to the display screen, and the light absorbing component includes a plurality of absorbing subcomponents disposed between the light emitting surface of the light source and the display screen.

In the embodiment of the present application, by setting a light-absorbing component composed of a plurality of miniature light-absorbing components, compared with a single light-absorbing component, the thickness of the light-absorbing component is greatly reduced, thereby reducing the overall thickness of the fingerprint identification device and expanding the fingerprint identification device. scope of application.

In a possible implementation, each of the sub-absorption components includes a first connection surface for coupling with the display screen, a first inclined surface, and a first connection surface connected between the first inclined surface and the first connection surface The first elevation between the two, the first inclined surface is at least partially coupled to the light source, the first connecting surface and the first inclined surface form a preset angle, and the preset angle is an acute angle.

In the embodiment of the present application, by arranging a light-absorbing component composed of a plurality of miniature light-absorbing sub-components and the first slope of each light-absorbing sub-component, while reducing the overall thickness of the fingerprint identification device, the ultrasonic signal generated by the light-absorbing component can be inclined The method is incident on the display screen, which improves the intensity of the ultrasonic signal absorbed by the ultrasonic receiving device, and improves the imaging quality and fingerprint recognition accuracy.

In a possible implementation, the length of the light source is half of the length of the ultrasonic receiving device.

Due to the characteristics of the ultrasonic receiving device itself, the absorption of the ultrasonic signal in the middle area is better. In the embodiment of the present application, the relationship between the length of the light source and the ultrasonic receiving device is limited, so that the ultrasonic signal reflected by the display screen can reach the ultrasonic wave. The middle area of the receiving device, thereby improving the conversion effect of the ultrasonic signal, improving the imaging quality and the accuracy of fingerprint identification.

In a possible implementation manner, the preset angle is determined by the thickness of the display screen, the size of the light absorbing member, the size of the ultrasonic receiving device, and the relative positional relationship between the light source and the ultrasonic receiving device Sure.

In the embodiment of the present application, the preset angle is set by the above-mentioned parameters, so as to determine a preferred preset angle to better improve the absorption rate of the ultrasonic signal by the ultrasonic receiving device, thereby improving the quality of ultrasonic imaging and the accuracy of fingerprint identification.

In a possible implementation manner, the preset angle θ satisfies the following relationship:

L ₂ +L ₁ +dL/sinθ≥2h ₁ ×tanθ≥L ₁ +d

Wherein, L ₂ is the length of the ultrasonic receiving device, L ₁ is the length of the second surface of the light absorbing member, L is the length of the light source, h ₁ is the thickness of the display screen, and d is the light absorption The distance between the component and the ultrasonic receiving device.

In a possible implementation manner, the preset angle θ satisfies the following relationship:

h×(cotθ+tanθ)=L

Wherein, L is the length of the light source, and h is the height of the light absorbing member.

In the embodiment of the present application, by calculating an appropriate preset angle, the reflected ultrasonic signal is absorbed by the ultrasonic receiving device as much as possible, and the absorption rate of the ultrasonic signal is improved, thereby improving the intensity of the echo signal, improving the imaging quality and fingerprint recognition. precision.

In a possible implementation manner, the light absorbing member includes a first surface coupled with the display screen and a second surface coupled with the light source, the first surface being parallel to the second surface.

In the embodiment of the present application, the light-absorbing component and the light source are arranged in a flat-mounting manner, so as to be better coupled with the display screen and improve the reliability of the coupling. At the same time, the flat-mounting manner is adopted, so that the ultrasonic signal generated by the light-absorbing component is vertically injected The display screen improves the intensity of the ultrasonic signal reaching the finger, thereby increasing the intensity of the ultrasonic echo signal corresponding to the fingerprint, and improving the accuracy of fingerprint recognition.

In a possible implementation manner, the light absorbing component is attached below the display screen through an ultrasonic coupling layer, the light absorbing component and the plane of the ultrasonic coupling layer form a groove, and the ultrasonic coupling layer fills the A groove is formed to couple the light absorbing member with the display screen.

In the embodiment of the present application, an acoustic lens formed by a light absorbing member with a groove or a concave upper surface absorbs light energy to generate an ultrasonic signal, which improves the focusing effect of the ultrasonic signal and improves the overall sensitivity of the fingerprint identification device.

In a possible implementation manner, the light absorbing member includes at least one strip-shaped groove, and the strip-shaped groove includes two oppositely arranged side walls and an arc-shaped bottom surface.

In the embodiment of the present application, an acoustic lens formed by a light absorbing member with one or more grooves absorbs light energy to generate an ultrasonic signal, which improves the focusing effect of the ultrasonic signal and improves the overall sensitivity of the fingerprint identification device.

In a possible implementation manner, the light source is a light emitting diode LED or a vertical cavity surface emitting laser VCSEL.

In a possible implementation manner, the period of the pulsed light is 1 ns˜80 ns.

In a possible implementation manner, the light source is elongated, and the light source is composed of a second preset number of LEDs.

In a possible implementation manner, the light absorbing member is a black silica gel material.

In one possible implementation, the black silicone material includes a concave upper surface to form an acoustic lens.

In the embodiment of the present application, the acoustic lens is formed by the concave surface of the black silica gel material, so that the deflection direction of the ultrasonic signal can be controlled, and the intensity of the echo signal and the quality of the fingerprint image can be improved.

In a possible implementation manner, the light-absorbing component includes a third preset number of black light-absorbing lattices composed of black silica gel materials.

In the embodiment of the present application, by setting the light-absorbing component in the form of a black light-absorbing lattice composed of black silica gel materials, on the premise of improving the light absorption rate, the light-absorbing component can be miniaturized in the form of a lattice, thereby reducing the overall size of the fingerprint identification device. , to increase the scope of application. In a possible implementation manner, the ultrasonic generating device further includes a driving module, and the driving module is configured to provide a driving signal for the light source, so as to control the light source to generate the pulsed light.

By setting the driving module of the light source in the embodiment of the present application, parameters such as the period and amplitude of the pulsed light output by the light source can be controlled, so as to realize the control of the generated ultrasonic signal and improve the controllability of the fingerprint identification device. At the same time, the use of a driver module with high response speed can improve the efficiency of fingerprint recognition.

In a second aspect, an embodiment of the present application provides a display screen module, including: a display screen and a fingerprint identification device provided by an embodiment corresponding to the first aspect and the optional manner of the first aspect of the present application.

In a third aspect, an embodiment of the present application provides an electronic device, which generally includes: a display screen and a fingerprint identification device provided by an embodiment corresponding to the first aspect and the optional manner of the first aspect of the present application.

The fingerprint identification device, the display screen module and the electronic equipment provided by the embodiments of the present application are composed of an ultrasonic generating device, an ultrasonic receiving device and a signal processing module. The device is attached to the lower part of the display screen through the ultrasonic coupling layer, and the light source is arranged on the surface of the light-absorbing component opposite to the display screen; based on the photoacoustic effect, the light-absorbing component absorbs the pulsed light of the light source to generate ultrasonic signals; the ultrasonic receiving device receives the fingerprint detected by the display screen. The echo signal of the ultrasonic signal returned by the finger above the area, and convert the echo signal into a fingerprint electrical signal; the signal processing module receives the fingerprint electrical signal, and generates a fingerprint image according to the fingerprint electrical signal, realizing the ultrasonic-based off-screen fingerprint recognition , Based on the strong penetration and high sensitivity of ultrasound, the accuracy of fingerprint identification is improved, and the fingerprint identification device has the advantages of simple design, easy implementation, strong scalability, etc., and reduces the cost of the fingerprint identification module.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present application, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

1 is a schematic diagram of a display screen to which a fingerprint identification device according to an embodiment of the present application is applicable;

2 is a schematic diagram of the installation of a fingerprint identification device provided by an embodiment of the present application;

FIG. 3 is a schematic structural diagram of a fingerprint identification device provided by an embodiment of the present application;

4A is a schematic structural diagram of a two-dimensional ultrasonic receiver array in the embodiment shown in FIG. 3 of the application;

4B is a schematic structural diagram of an ultrasonic receiver in the embodiment shown in FIG. 4A of the application;

5 is a schematic structural diagram of a fingerprint identification device provided by another embodiment of the present application;

6A is a schematic structural diagram of a fingerprint identification device provided by another embodiment of the present application;

6B is a schematic structural diagram of a fingerprint identification device provided by another embodiment of the present application;

6C is a schematic diagram of the position of a light absorbing component provided by an embodiment of the present application;

6D is a schematic diagram of the position of a light absorbing component provided by another embodiment of the present application;

FIG. 6E is an equivalent schematic diagram of the light absorbing member in the embodiment shown in FIG. 6D of the present application;

7 is a schematic structural diagram of a fingerprint identification device provided by another embodiment of the present application;

FIG. 8 is a schematic structural diagram of the light absorbing component in the embodiment shown in FIG. 5 of the application;

9 is a schematic structural diagram of a display screen module provided by an embodiment of the present application;

10A is a schematic front view of an electronic device according to an embodiment of the present application;

FIG. 10B is a schematic cross-sectional view of the electronic device shown in FIG. 10A .

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments It is a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

The technical solutions of the present application will be described in detail below with specific examples. The following specific embodiments may be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

At present, OLED screens and liquid crystal display (LCD) screens are self-luminous display screens and non-self-luminous display screens that are widely used in electronic devices such as smart mobile terminals, respectively. OLED screen is a current-type organic light-emitting device, which has many advantages such as thin body, power saving, wide viewing angle, extremely high response speed, high contrast, etc., and is widely used in electronic products such as televisions, computers, and mobile phones.

In the scenario of fingerprint recognition for the screen, most of them rely on the optical fingerprint recognition technology for off-screen fingerprint recognition. By arranging the optical fingerprint sensor under the OLED screen, the self-luminous display pixels of the OLED screen can be used as the fingerprint excitation light source for the screen. Lighting, specifically, the self-luminous display pixels located in the fingerprint detection area in the OLED screen are driven to emit light to display a light spot in the fingerprint detection area, and the light emitted by the OLED screen is used as the excitation light for fingerprint recognition to illuminate the finger above the OLED screen. , and after being scattered, reflected or transmitted by the finger, the fingerprint detection light carrying the fingerprint information of the finger is formed. The fingerprint detection light returns to the OLED screen and is transmitted to the optical fingerprint sensor below through the OLED screen, and the optical fingerprint sensor can receive the fingerprint. Detecting light and converting the fingerprint detection light into corresponding electrical signals, thereby realizing fingerprint image collection.

However, as the light transmittance of the OLED screen is getting lower and lower, the signal of the fingerprint detection light passing through the OLED screen is getting weaker and weaker, which makes the accuracy of the optical-based fingerprint recognition technology low and cannot meet the needs of users.

With the continuous development of ultrasonic transducer technology, fingerprint recognition technology based on ultrasonic transducers has emerged, specifically based on ultrasonic transducers to generate and receive ultrasonic waves, and then perform fingerprint imaging and recognition. The main body of receiving and sending makes the wiring and structural design of the ultrasonic transducer complex, and also needs to take into account issues such as transceiver coupling, which leads to the high cost of the fingerprint identification device.

The inventive concept of the fingerprint identification device, the display screen module and the electronic device provided by the embodiments of the present application is to separate the receiving and transmitting of the ultrasonic signal, that is, the ultrasonic signal is generated by the ultrasonic generating device, and the ultrasonic signal is received by the ultrasonic receiving device or the ultrasonic receiver. The echo information corresponding to the signal reduces the complexity and design cost of the ultrasonic receiver wiring, and at the same time, the fingerprint recognition based on the ultrasonic improves the accuracy of the fingerprint recognition.

The technical solutions in the present application will be described below with reference to the accompanying drawings.

The fingerprint identification device provided by the embodiment of the present application can be applied to the electronic device provided by the embodiment of the present application, wherein the electronic device can be a smart phone, a camera, a tablet computer, a notebook computer, a smart watch, a game device, a fingerprint punching machine, a fingerprint Payment terminals and other mobile terminals or other terminal devices with a fingerprint identification function are not limited in this embodiment of the present application.

1 is a schematic diagram of a display screen to which a fingerprint identification device provided by an embodiment of the present application is applicable. It should be understood that the fingerprint identification device provided by the present application can also be applied to other fingerprint entry devices other than the display screen. Such as glass, solid cover, flat plate, etc., the thickness of the fingerprint entry device should be less than or equal to 3mm, and meet the needs of ultrasonic signal transmission, such as a device with low acoustic impedance, so that the ultrasonic signal can pass through the fingerprint entry device. Fingerprints are imaged. FIG. 2 is a schematic diagram of installation of a fingerprint identification device provided by an embodiment of the present application. The display screen can be an OLED screen, the thickness of the display screen should be less than or equal to 3mm, and can perform fingerprint imaging and transmit ultrasonic signals at the same time. As shown in FIG. 1 and FIG. 2 , the fingerprint identification device provided by the present application is arranged below the display screen to identify the user's fingerprint.

With reference to FIGS. 1 and 2 , the display screen 100 has a fingerprint detection area 111 . It can be understood that at least part of the fingerprint detection area 111 should be located in the display area of the display screen 100 . When the finger 200 is located on the fingerprint detection area 111 in the display area of the display screen 100, the ultrasonic signal S1 used for fingerprint recognition passes through the finger 200 in the fingerprint detection area 111 to generate an echo signal S2. The fingerprint identification device 300 receives and converts to generate a fingerprint electrical signal, and then the corresponding signal processing module generates a fingerprint image of the finger 200 according to the fingerprint electrical signal, and the fingerprint image can be further used for identification to authenticate the user.

In some embodiments, the fingerprint detection area 111 may all be located in the display area of the display screen 100 , so that the user can perform fingerprint identification at any position on the display screen 100 , and at the same time, the integrity of the collected fingerprint image can be improved.

Correspondingly, the fingerprint identification devices 300 may also be formed in multiple groups, and identify the fingerprints in the regions according to the corresponding fingerprint detection regions 111 .

FIG. 3 is a schematic structural diagram of a fingerprint identification device provided by an embodiment of the present application. As shown in FIG. 3 , the fingerprint identification device 300 provided by an embodiment of the present application may include: an ultrasonic generating device 310 , an ultrasonic receiving device 320 and a signal processing module 330 , the ultrasonic generating device 310 includes a light source 311 and a light absorbing component 312 , the light absorbing component 312 and the ultrasonic receiving device 320 are attached to the bottom of the display screen 100 , and the light source 311 is arranged on the side of the light absorbing component 312 away from the display screen 100 .

The light source 311 is used to generate pulsed light; the light absorption component 312 is used to absorb the pulsed light and generate an ultrasonic signal; the ultrasonic receiving device 320 is used to receive the ultrasonic signal returned by the finger above the fingerprint detection area of the display screen 100 The echo signal is converted into a fingerprint electrical signal; the signal processing module 330 is connected to the ultrasonic receiving device 320 for receiving the fingerprint electrical signal and generating a fingerprint image according to the fingerprint electrical signal.

Specifically, the ultrasonic receiving device 320 may be attached below the display screen 100 through the ultrasonic coupling layer. The ultrasonic coupling layer can reduce the ultrasonic impedance, thereby increasing the intensity of the ultrasonic signal transmitted to the upper part of the display screen 100 and improving the imaging quality.

Specifically, the light source 311 can be disposed on the surface of the light absorbing member 312 opposite to the display screen 100 , or disposed on any surface except the light absorbing member 312 coupled with the display screen 100 , or can be disposed on the light absorbing member 312 away from the display screen 100 . one side of . For example, when the light absorbing member 312 is in the shape of a strip, the display screen 100 and the light source 311 can be arranged on two opposite surfaces of the strip, and when the light absorbing member 312 is in the shape of a wedge, the display screen 100 and the light source 311 can be arranged in the wedge shape Alternatively, the display screen 100 is arranged on the top surface of the light absorbing member 312, and the light source 311 is arranged below the bottom edge of the light absorbing member 312, as long as the light absorbing member 312 can absorb the light signal emitted by the light source 311 to convert it into Ultrasound signal is enough.

Specifically, when the light source 311 generates pulsed light to illuminate the light-absorbing member 312, after the molecules in the light-absorbing member 312 absorb the photons in the pulsed light, when certain conditions are met, the electrons of the molecules that absorb the energy transition from a low energy level to a high energy level and In the excited state, the electrons in the excited state are extremely unstable. When the electrons transition from a high energy level to a low energy level, they will release energy in the form of heat, and the released heat will cause the local temperature of the light absorbing member 312 to increase. The thermal expansion generates pressure waves, thereby generating ultrasonic signals, that is, the ultrasonic generating device 310 generates ultrasonic signals based on pulsed light. That is, the light absorbing member 312 converts the light energy of the absorbed pulsed light into thermal energy, and then converts the thermal energy into mechanical energy. By selecting an appropriate wavelength of the pulsed light, the efficiency of the light absorbing member 312 in converting light energy into heat energy can be improved.

The method for generating ultrasonic signals based on pulsed light provided by the present application has a wider bandwidth of the ultrasonic signals compared to the traditional method for generating ultrasonic signals based on the integrated receiving and transmitting ultrasonic transducers, so that the ultrasonic generating device 310 and the ultrasonic receiving device 320 have a wider bandwidth. The transient response is better than that of the existing transceiver integrated ultrasonic transducer.

Specifically, when the finger 200 is pressed above the display screen 100, such as the fingerprint detection area 111, the ultrasonic signal generated by the ultrasonic generating device 310 is refracted to the upper surface of the display screen 100 through the lower surface of the display screen 100. There is a difference with the acoustic impedance of the upper surface of the display screen 100, so that the valley ridge of the fingerprint of the finger 200 is different from the echo signal of the ultrasonic signal corresponding to the display screen 100, so the echo signal of the ultrasonic signal will carry the fingerprint information of the finger 200. The receiving device 320 collects the echo signal, converts the echo signal into a corresponding fingerprint electrical signal, and generates a fingerprint image of the finger 200 through signal processing by the signal processing module 330 to authenticate the fingerprint image.

Specifically, the light source 311 is disposed on the lower surface of the light-absorbing member 312, the upper surface of the light-absorbing member 312 is attached to the lower surface of the display screen 100 through the ultrasonic coupling layer, and the user performs fingerprint input through the upper surface of the display screen 100, such as fingerprint unlocking, Fingerprint payment, etc.

The main function of the ultrasonic coupling layer is to reliably paste the fingerprint identification device 300 under the display screen 100 , and the ultrasonic coupling layer may also have an ultrasonic coupling function. In some embodiments, the ultrasonic coupling layer may be glue or other viscous adhesive layers, or may be an ultrasonic coupling agent, such as any one of glycerin, gel, mineral oil, vegetable oil, etc., which is not discussed in this application. be limited.

In some embodiments, the period of the pulsed light generated by the light source 311 may be between 1 ns˜80 ns, such as 5 ns, 10 ns, 15 ns, 30 ns, 60 ns, or other values. Correspondingly, the wavelength of the light absorbing member 312 should correspond to the period of the pulsed light, so as to absorb light energy.

In some embodiments, the light source 311 can be a light emitting diode (Light Emitting Diode, LED) or a vertical cavity surface emitting laser (Vertical-Cavity Surface-Emitting Laser, VCSEL), of course, other devices can also be selected as the light source. Not limited.

In some embodiments, the ultrasound receiving device 320 may take the shape of an elongated strip. Correspondingly, the light source 311 and the light absorbing member 312 may also be elongated. The use of elongated components is more conducive to the splicing or coupling between the components and improves the coupling reliability of the fingerprint identification device. Specifically, the strip-shaped light source may be composed of a second preset number of LEDs. Wherein, the second preset number may be 2, 5, 10 or other numbers, which may be specifically determined according to requirements.

In some embodiments, the ultrasonic generating device 310 composed of the light absorbing member 312 and the light source 311 may be respectively disposed on two sides corresponding to the two long sides of the ultrasonic receiving device 320 , thereby increasing the contact area between the ultrasonic generating device 310 and the ultrasonic receiving device 320 , so that the ultrasonic receiving device 320 can absorb more ultrasonic signals and improve the absorption rate of the ultrasonic signals, thereby improving the imaging quality of the fingerprint signal and improving the accuracy of fingerprint identification.

In some embodiments, the ultrasonic generating devices 310 may be respectively disposed around the ultrasonic receiving device 320 to further increase the contact area.

Specifically, a plurality of LEDs can be evenly arranged along the long side of the light-absorbing member 312 to increase the power of the pulsed light, so that the light-absorbing member 312 can absorb more light energy, thereby generating a strong ultrasonic signal to improve the fingerprint Image quality and fingerprint recognition accuracy.

In some embodiments, the elongated light source can be obtained by closely laying bare LED chips.

In some embodiments, the light-absorbing material used in the light-absorbing member 312 may be a black material, so as to improve the efficiency of photoacoustic conversion. The light-absorbing member 312 should preferably be a material with high light-absorbing efficiency, such as a light-absorbing material with a light attenuation rate of at least 90%.

In some embodiments, the light-absorbing material of the light-absorbing member 312 is a black silica gel material.

In some embodiments, the thickness of the light absorbing member 312 may be on the order of microns, such as 3 μm, 5 μm, 8 μm, or other values.

In some embodiments, the ultrasonic generating device 310 further includes a driving module 313, and the driving module 313 is configured to provide a driving signal for the light source 311 to control the light source 311 to generate the pulsed light.

Specifically, the driving module 313 may generate a driving signal according to an instruction or autonomously, so as to control the light source 311 to generate pulsed light.

In some embodiments, the driver module 313 may be a high-speed, high-current, high-power driver module. For example, it can be designed by using a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor, metal-oxide semiconductor field effect transistor or MOS tube) with a high response speed. The driving time of the driving module 313 for generating the driving signal may be controlled by a logic IO (Input Output, input output) circuit.

The light source 311 is rapidly driven by the driving module 313 to generate pulsed light, which improves the response speed of fingerprint identification.

Specifically, the ultrasonic coupling layer can be used to reduce the acoustic impedance of the display screen 100 to increase the strength of the echo signal of the ultrasonic signal.

In some embodiments, the ultrasound receiving device 320 may be a two-dimensional ultrasound receiver array consisting of a first preset number of ultrasound receivers. The two-dimensional ultrasonic receiver array is disposed below the fingerprint detection area 111 of the display screen 100 to receive echo signals of ultrasonic signals.

In some embodiments, the scanning mode of the two-dimensional ultrasound receiver array may be line scanning or area scanning.

In some embodiments, the first preset number may be 32, 64, 128, or other values.

In some embodiments, the two-dimensional ultrasonic receiver array is in the shape of a square, such as a rectangle, the length of the square is at least 9 mm and the width is at least 4 mm, so as to meet the scene requirements of fingerprint recognition.

Specifically, the size of the fingerprint detection area 111 of the display screen 100 is usually 4*9mm ² or 6*6mm ² . In order to ensure that the ultrasonic signal returned by the fingerprint detection area 111 can be completely received, the ultrasonic sensor corresponding to the two-dimensional ultrasonic receiver array The size of the area is greater than or equal to the size of the fingerprint detection area 111 . The width range of the ultrasonic sensing area formed by the two-dimensional ultrasonic receiver array can be set to 4mm to 8mm, and the length range can be set to 9mm to 15mm to ensure that enough fingerprint signals can be received for fingerprint identification.

In some embodiments, the ultrasonic receivers of the two-dimensional ultrasonic receiver array can be manufactured by using a MEMS (Microelectromechanical System, micro-electromechanical system) process, so as to improve the performance of the ultrasonic receiver, such as sensitivity, resolution, pressure resistance, and the like. At the same time, the two-dimensional ultrasonic receiver array manufactured by the MEMS process can avoid the high-voltage CMOS (Complementary Metal Oxide Semiconductor) process required for the manufacture of the integrated ultrasonic transducer array, and use the low-voltage CMOS process to produce The two-dimensional ultrasound receiver array and other related components, thereby reducing the manufacturing cost. Compared with the integrated transceiving ultrasonic transducer, the two-dimensional ultrasonic receiver array provided by the embodiment of the present application has simpler structural design and higher sensitivity, thereby reducing the cost of the fingerprint identification device and improving the quality of fingerprint imaging.

In some embodiments, each ultrasonic receiver of the two-dimensional ultrasonic receiver is provided with a first electrode and a second electrode, and the first electrode and the second electrode are respectively provided on two sides of the piezoelectric material of the ultrasonic receiver, so as to After the piezoelectric layer receives the echo signal of the ultrasonic signal, an induced charge is generated, and the induced charge is the fingerprint electrical signal, which is then transmitted to the signal processing module 330 through the first electrode and the second electrode for signal processing to generate a fingerprint image. .

Exemplarily, FIG. 4A is a schematic structural diagram of the two-dimensional ultrasonic receiver array in the embodiment shown in FIG. 3 of the present application. As shown in FIG. 4A , the two-dimensional ultrasonic receiver array includes a plurality of ultrasonic receivers 321, which are composed of The ultrasonic receivers 321 form a two-dimensional array, and the two-dimensional array can be replicated and expanded. A schematic structural diagram of each ultrasonic receiver 321 is shown in FIG. 4B . 4B is a schematic structural diagram of the ultrasonic receiver in the embodiment shown in FIG. 4A of the application. As shown in FIG. 4B , the ultrasonic receiver 321 of the two-dimensional ultrasonic receiver array includes a support portion 3211 , a piezoelectric layer 3212 , and a first electrode 3213 and the second electrode 3214.

In some embodiments, the second electrode 3214 disposed on the ultrasonic receiver 321 may be disposed at any position on the upper surface of the piezoelectric layer 3212 to form a passage with the first electrode 3213, so as to transmit the piezoelectric layer 3212 based on ultrasonic signals The induced charge generated by the echo signal.

In some embodiments, the second electrode 3214 or the first electrode 3213 of the ultrasound receiver 321 of the two-dimensional ultrasound receiver array may be determined by addressing.

In some embodiments, the piezoelectric material of the piezoelectric layer 3212 of the ultrasonic receiver 321 may be AlN aluminum nitride material, modified aluminum nitride material, PVDF polyvinylidene fluoride material, or lead zirconate titanate thin film material (PZT) . Of course, other piezoelectric materials with higher piezoelectric conversion coefficients can also be selected, which are not limited in this application.

In some embodiments, the first electrode 3213 and the second electrode 3214 may be metals, such as copper, aluminum, and the like.

In some embodiments, the support portion 3211 may be monocrystalline silicon, polycrystalline silicon, or other materials.

In some embodiments, the signal processing module 330 is electrically connected to the ultrasonic receiving device 320, receives the fingerprint electrical signal of the ultrasonic receiving device 320, and performs signal processing on the fingerprint electrical signal to obtain a fingerprint image. The signal processing includes noise reduction processing, signal conversion processing, and fingerprint image rendering.

In some embodiments, the signal processing module 330 may be an ASIC (Application Specific Integrated Circuit), a conditioning circuit and an MCU (Microcontroller Unit), or a conditioning circuit, an ADC (Analog to Digital Converter, analog-to-digital converter) and FPGA (Field Programmable Gate Array, Field Programmable Gate Array), etc. Of course, other devices can also be used to design the signal processing module 330, which is not limited in this application.

The fingerprint identification device provided in this embodiment is composed of an ultrasonic generating device, an ultrasonic receiving device and a signal processing module. The ultrasonic generating device includes a light source and a light-absorbing component. The light-absorbing component and the ultrasonic receiving device are attached to the display screen through the ultrasonic coupling layer. Below, the light source is arranged on the surface of the light-absorbing component opposite to the display screen; the light-absorbing component absorbs the pulsed light of the light source based on the photoacoustic effect to generate an ultrasonic signal; the ultrasonic receiving device receives the ultrasonic signal returned by the finger above the fingerprint detection area of the display screen. wave signal, and convert the echo signal into fingerprint electrical signal; the signal processing module receives the fingerprint electrical signal, and generates a fingerprint image according to the fingerprint electrical signal, which realizes the fingerprint recognition under the screen based on ultrasound, and has strong penetration and high performance based on ultrasound. The sensitivity improves the accuracy of fingerprint identification, and at the same time, the fingerprint identification device has the advantages of simple design, easy implementation, strong expandability, etc., and reduces the cost of the fingerprint identification module.

In some embodiments, the ultrasonic generating device 310 is disposed on both sides of the ultrasonic receiving device 320 to increase the intensity of the ultrasonic signal.

In some embodiments, the light absorbing member 312 includes a first surface and a second surface, the first surface is coupled with the display screen 100, the second surface is coupled with the light source 311, the first surface and the The plane on which the second surface is located is parallel to the plane on which the display screen 100 is located, so that the light-absorbing member 312 is flatly attached to the display screen 100, and the ultrasonic signal emitted by the light-absorbing member 312 can be vertically incident on the display screen 100, so that more The ultrasonic signal is returned to the ultrasonic receiving device 320 through the finger, so as to increase the intensity of the fingerprint signal and improve the imaging quality.

In some embodiments, the plane where the second surface is located is at a preset angle with the plane where the display screen is located, and the preset angle is an acute angle, so that the light-absorbing member 312 is attached to the display screen 100 in an inverted wedge shape, and absorbs light. The ultrasonic signal emitted by the component 312 is incident on the display screen 100 in an oblique manner, so that part of the ultrasonic signal is returned to the ultrasonic receiving device 320 through the finger, and part of the ultrasonic signal is absorbed by the ultrasonic receiving device 320 after being reflected by the display screen 100, which enhances the return. The strength of the ultrasonic signal, thereby improving the quality of fingerprint imaging.

In some embodiments, the preset angle may be between 15° and 60°, such as 30°, 45°, and the like.

In the embodiment of the present application, the light-absorbing component is arranged on the display screen at a certain angle, so that the ultrasonic signal generated by the ultrasonic generating device can be emitted on the display screen at a certain angle, thereby improving the echo of the ultrasonic signal returned through the display screen. The strength of the signal improves the quality of ultrasound imaging and the accuracy of fingerprint identification.

In some embodiments, the plane where the light absorbing member 312 is coupled with the second coupling surface is recessed downward to form a groove, and the ultrasonic coupling layer fills the groove, so that the light absorbing member 312 is coupled with the display screen 100 .

In the embodiment of the present application, the acoustic lens formed by the light-absorbing component with a concave plane absorbs light energy to generate an ultrasonic signal, which improves the focusing effect of the ultrasonic signal and improves the overall sensitivity of the fingerprint identification device.

In some embodiments, the shape of the light absorbing member 312 is a wedge shape or a rectangular parallelepiped shape. The light-absorbing member 312 in the shape of a cuboid can be more reliably coupled with the display screen, and the ultrasonic signal generated by the light-absorbing member 312 is vertically incident on the display screen 100 to increase the intensity of the ultrasonic signal corresponding to the finger, thereby increasing the intensity of the echo signal. Improve image quality. Using the wedge-shaped light absorbing member 312 can make the ultrasonic signal incident on the display screen 100 in an oblique manner, so that part of the ultrasonic signal is reflected, and part of the ultrasonic signal is transmitted to the upper part of the display screen 100 and returned to the ultrasonic receiving device 320 through the finger. Part of the ultrasonic signal increases the intensity of the ultrasonic signal absorbed by the ultrasonic receiving device 320, thereby improving the imaging quality and fingerprint identification accuracy.

FIG. 5 is a schematic structural diagram of a fingerprint identification device provided by another embodiment of the application. This embodiment further describes the positional relationship of each component on the basis of the embodiment shown in FIG. 3 . Flatly attached under the display screen, the ultrasonic receiving device in this embodiment is a two-dimensional ultrasonic receiver array. As shown in FIG. 5 , the fingerprint identification device includes a light source 510, a light-absorbing component 520, a two-dimensional ultrasonic Coupling layer 540 and signal processing module.

The first surface s1 of the light absorbing member 520 is coupled with the light source 510, and the second surface s2 is coupled with the display screen 100 through the ultrasonic coupling layer 540. It can be seen from FIG. 5 that the first surface s1 and the second surface s2 are parallel.

As can be seen from FIG. 5 , the fingerprint identification device provided in this embodiment is disposed below the display screen 100 , the ultrasonic coupling layer 540 is arranged from top to bottom, the light absorbing member 520 and the two-dimensional ultrasonic receiving layer are disposed under the ultrasonic coupling layer 540 The two-dimensional ultrasonic receiver array 530 is elongated, the light absorbing components 520 are arranged on both sides of the long side of the two-dimensional ultrasonic receiver array 530, and the light source 510 is arranged below each light absorbing component 520. The light source 510 is used to output pulsed light, and the corresponding light-absorbing component 520 absorbs the pulsed light to generate an ultrasonic signal, which is transmitted to the upper part of the display screen 100 through the ultrasonic coupling layer 540, and returns to the two-dimensional ultrasonic receiver array 530 after passing through the finger. , is absorbed by it, so as to obtain the corresponding fingerprint signal for fingerprint imaging.

In some embodiments, the ultrasonic generating devices located on the left and right sides of the two-dimensional ultrasonic receiver array 530 are the same, that is, the light absorbing components 520 of the first part and the second part have the same parameters except for the different placement positions, and the first part and the second part have the same parameters. The light source 510 corresponding to the light absorbing member 520 of the second part is also the same light source.

Specifically, the lengths of the light absorbing component 520 and the light source 510 may be equal, so that the light absorbing component 520 can absorb more pulsed light and increase the intensity of the ultrasonic signal output by the light absorbing component 520 . The light absorbing components 520 may be disposed adjacent to the two-dimensional ultrasonic receiver array 530, or may be disposed at a distance. In FIG. 5, the adjacent arrangement is taken as an example.

FIG. 6A is a schematic structural diagram of a fingerprint identification device provided by another embodiment of the present application. In this embodiment, the light-absorbing component is attached under the display screen in an inverted wedge shape. It can be seen from FIG. 5 and FIG. 6A that the light-absorbing component 520 in this embodiment is The ultrasonic coupling layer 540 is attached under the display screen 500 in an inverted wedge shape, and the light absorbing component 520 in FIG.

Specifically, the inclined surface s1 of the light absorbing member 520 is coupled with the light source 510, the connecting surface s2 of the light absorbing member 520 is coupled with the display screen 100, and the light absorbing member 520 further includes a vertical surface s3, which is connected between the inclined surface s1 and the connecting surface s2 , the façade s3 is coupled with one side of the long side of the two-dimensional ultrasound receiver array 530 .

Specifically, the light source 510 is elongated and arranged in parallel with the inclined plane s1; the connecting surface s2 of the light absorbing member 520 is coupled to the display screen 100 through the ultrasonic coupling layer 540, the inclined plane s1 and the connecting plane s2 are at a preset angle θ, and the preset The angle θ is an acute angle.

Specifically, the light-emitting surface s4 of the light source 510 is parallel to the inclined surface s1 of the light-absorbing member 520, so that the pulsed light output by the light source 510 enters the light-absorbing member 520 in a vertical form, thereby increasing the intensity of the pulsed light absorbed by the light-absorbing member 520, thereby increasing the The strength of the resulting ultrasound signal.

The inclined light source 510 is used, so that the ultrasonic signal b generated after the light absorbing member 520 absorbs the pulsed light is incident on the display screen 100 at a certain angle, so that part of the ultrasonic signal b is reflected, and its echo signal is absorbed by the two-dimensional ultrasonic receiver array 530, Thus, the intensity of the echo signal is enhanced, thereby enhancing the imaging quality of the fingerprint.

Further, the facade s3 may be perpendicular to the connecting surface s2. Therefore, the facade s2 can be better coupled with the two-dimensional ultrasonic receiver array 530, the coupling reliability is improved, and the contact area is increased, so that the two-dimensional ultrasonic receiver array 530 absorbs more ultrasonic signals.

Further, in this embodiment, the longitudinal section of the light absorbing member 520 is a triangle, which may be a right-angled triangle or an acute-angled triangle, and a right-angled triangle is used as an example in FIG. 6A .

In some embodiments, the preset angle is determined by the thickness of the display screen 100, the size of the light absorbing member, the size of the ultrasonic receiving device, and the relative positional relationship between the light source and the ultrasonic receiving device.

In some embodiments, in order to improve the absorption rate of the ultrasonic signal absorbed by the two-dimensional ultrasonic receiver array 530, the length of the two-dimensional ultrasonic receiver array 530 may be set to be twice the length of the light source.

In some embodiments, the light-emitting surface s4 of the light source 510 is parallel to the display screen 100, and the light-absorbing component 520 includes a plurality of light-absorbing sub-components disposed between the light-emitting surface of the light source and the display screen. The plurality of absorbing sub-components may be arranged in a row or two-dimensionally below the display screen 100 .

Specifically, by using a light-absorbing component composed of individual light-absorbing components with smaller sizes, the thickness of the light-absorbing component can be greatly reduced, thereby reducing the overall thickness of the fingerprint identification device, reducing the installation requirements of the fingerprint identification device, and expanding the application range.

FIG. 6B is a schematic structural diagram of a fingerprint identification device provided by another embodiment of the present application. It can be seen from FIG. 6A and FIG. 6B that the light absorbing component 520 in this embodiment includes a plurality of absorbing sub-components 521 .

Wherein, each sub-absorption component 521 includes a first connection surface t1, a first inclined surface t2 and a first vertical surface t3, the first connection surface t1 is coupled with the display screen 100 through the ultrasonic coupling layer, and at least part of the first inclined surface t2 is connected to the light source 510 coupling, the first elevation t3 is connected between the first inclined surface t2 and the first connecting surface t1, the first connecting surface t1 and the first inclined surface t2 form a preset angle θ, and the preset angle θ is an acute angle.

In some embodiments, the longitudinal cross-section of each sub-absorption component is a right-angled triangle or an acute-angled triangle.

In some embodiments, the first inclined surface t2 and the first vertical surface t3 intersect on a straight line, and the intersecting line is coupled with the light exit surface s4 of the light source 510 .

Specifically, the number of the absorbing sub-components needs to be determined according to size information such as the size of the absorbing sub-components, the size of the fingerprint detection area, and the like.

FIG. 6C is a schematic diagram of the position of a light-absorbing component provided by an embodiment of the present application. As shown in FIG. 6C , a single light-absorbing component is used in this embodiment. The rectangular structure in the middle represents the ultrasonic receiving device, and the triangles located on both sides of the ultrasonic receiving device represent the light-absorbing components respectively. components, the rectangle below each light absorbing component represents the light source, wherein the length of the ultrasonic receiving device is L ₂ , the length of the light source is L, the height of the light absorbing component is h, the length of the light absorbing component is L ₁ , and the wedge angle of the light absorbing component That is, the above-mentioned preset angle is θ. In this embodiment, the light absorbing member is arranged next to the ultrasonic receiving device.

FIG. 6D is a schematic diagram of the position of a light absorbing component provided by another embodiment of the present application. As shown in FIG. 6D , different from FIG. 6C , the light absorbing component in this embodiment is composed of a plurality of miniaturized absorbing subcomponents. , the triangle in Figure 6D represents the absorbing subcomponent. In this embodiment, the shape of the longitudinal section of the absorbing subcomponent is a right triangle. The overall length of the plurality of light absorbing components may be the same as the length of the corresponding light source, and both are L.

FIG. 6E is an equivalent schematic diagram of the light-absorbing component in the embodiment shown in FIG. 6D of the present application. As shown in FIG. 6E , the light-absorbing component composed of a plurality of miniaturized wedge-shaped light-absorbing sub-components can be equivalent to a larger wedge-shaped light-absorbing component. component, the wedge angle of the equivalent light absorbing component is the same as the wedge angle of a single absorbing subcomponent, and both can be the above-mentioned preset angle θ. That is to say, a light-absorbing component composed of multiple miniaturized light-absorbing sub-components can achieve the same effect of emitting ultrasonic signals in an oblique manner as using a single light-absorbing component. thickness, thereby facilitating the miniaturization of the overall structure.

In some embodiments, including the embodiments corresponding to the above-mentioned FIGS. 6A to 6D , the preset angle θ satisfies:

h×(cotθ+tanθ)=L

Wherein, h is the height of the light absorbing member, and L is the length of the light source. When the light absorbing component includes multiple absorbing sub-components, the height of the light absorbing component is the height of the light absorbing component equivalent to the multiple absorbing sub-components, that is, h in FIG. 6E .

In some embodiments, including the embodiments corresponding to the above-mentioned FIGS. 6A to 6D , the preset angle θ may also satisfy the following relationship:

L ₂ +L ₁ +dL/sinθ≥2h ₁ ×tanθ≥L ₁ +d

Wherein, L ₂ is the length of the ultrasonic receiving device, L ₁ is the length of the second surface s2 of the light-absorbing component, L is the length of the light source, h ₁ is the thickness of the display screen, d is the distance between the light-absorbing component and the ultrasonic receiving device, and d is the distance between the light-absorbing component and the ultrasonic receiving device. The value can be 0 or greater than 0.

Specifically, after the ultrasonic signal in the direction indicated by the arrow in FIG. 6B or FIG. 6A is transmitted once through the display screen, the corresponding path in the horizontal direction is 2h ₁ ×tanθ. In order to ensure that the ultrasonic signal in this direction can be reflected as much as possible to For the ultrasonic receiving device, it is necessary to ensure that the minimum value of the path is L ₁ +d, so that the ultrasonic signal in the direction farthest from the ultrasonic receiving device can reach the ultrasonic receiving device, and the maximum value of the path is L ₂ +L ₁ +dL/sinθ, to ensure that the ultrasonic signal in the direction closest to the ultrasonic receiving device will not exceed the ultrasonic receiving device, so that the ultrasonic receiving device can receive more ultrasonic signals reflected by the display screen.

Specifically, when the preset angle θ satisfies the above expression, the ultrasonic signal output by the light-absorbing component can be absorbed as much as possible by the ultrasonic receiving device after being reflected once, so as to avoid multiple reflections and attenuate the ultrasonic signal as much as possible. The intensity of the reflected part of the ultrasonic signal is improved, thereby increasing the intensity of the ultrasonic echo signal received by the ultrasonic receiving device and improving the imaging quality.

Specifically, the preset angle θ can be understood as a wedge-shaped angle at which the light-absorbing component is attached to the lower part of the display screen in a wedge shape or an inverted wedge shape.

In some embodiments, in order to improve the absorption rate of the ultrasonic signal absorbed by the ultrasonic receiving device, the length L ₂ of the ultrasonic receiving device may be set to be twice the length L of the light source.

FIG. 7 is a schematic structural diagram of a fingerprint identification device according to another embodiment of the present application. The fingerprint identification device 700 in this embodiment includes multiple light sources, light absorbing components and ultrasonic receiving devices. As shown in FIG. 7 , the ultrasonic generating device in this embodiment includes multiple groups of light sources 711 and light absorbing components 721 , and the ultrasonic receiving device includes multiple groups of two-dimensional ultrasonic receiver arrays 720 . That is, the ultrasonic receiving device, the light source and the light absorbing component in the fingerprint identification device provided by this application can be replicated and expanded to form multiple groups of ultrasonic generating modules and ultrasonic receiving modules, each group of ultrasonic generating modules is composed of one or more light sources 711 and light sources. 711 is composed of a corresponding number of light-absorbing components 721, and each group of ultrasonic receiving modules is composed of one or more ultrasonic receiving devices 720, which receive echo signals corresponding to fingerprints in a distributed manner to increase the receiving area of echo signals of ultrasonic signals. , thereby increasing the area of the fingerprint detection area, so as to obtain a more complete fingerprint electrical signal, and at the same time, the convenience of fingerprint authentication for the user is improved.

FIG. 8 is a schematic structural diagram of the light-absorbing component in the embodiment shown in FIG. 5 of the present application. As shown in FIG. 8 , the light-absorbing component in this embodiment is a black silica gel component 820 , and the light-absorbing material of the black silica gel component 820 is a black silica gel material , the black silicone part 820 includes a concave upper surface to form an acoustic lens, and the black silicone part 820 is coupled with the display screen through the ultrasonic coupling layer 840 .

Specifically, the upper surface of the black silicone part 820 in this embodiment is recessed downward to form a groove 821. Correspondingly, the ultrasonic coupling layer 820 fills the groove 821, so that the black silicone material 820 is pasted under the display screen, which may be It is connected to the display screen in the form of an inverted wedge or tile. The acoustic lens formed by the concave upper surface of the black silicone part 820, that is, the above-mentioned groove 821, can control the deflection direction of the ultrasonic signal and play the role of focusing, thereby increasing the intensity of the ultrasonic signal, thereby increasing the intensity of the echo signal, improving the intensity of the echo signal. Fingerprint imaging quality.

In some embodiments, the groove 821 is a strip-shaped groove, including two oppositely arranged side walls and an arc-shaped bottom surface. The number of grooves 821 may be one or more, which is not limited in this application.

In some embodiments, the light absorbing component includes a black light absorbing lattice composed of a third preset number of black silicone components 820, and the upper surface of the black light absorbing lattice is concave downward to form grooves to form an acoustic lens to improve the ultrasonic signal Strength of.

FIG. 9 is a schematic structural diagram of a display screen module according to an embodiment of the present application. As shown in FIG. 9 , the display screen module includes a display screen 910 and a fingerprint identification device 920 .

Wherein, the display screen 910 may be an OLED screen, or another screen with a relatively thin thickness, such as less than or equal to 3 mm, and which can transmit ultrasound. The fingerprint identification device 920 is disposed below the display screen 910 , and may be the fingerprint identification device provided in any one of the embodiments corresponding to FIGS. 2 to 8 of the present application.

Specifically, in this embodiment, reference may be made to the description of the fingerprint identification device and the display screen in the embodiments corresponding to FIGS. 2 to 8 . In this embodiment, the fingerprint identification device and the display screen will not be further described.

10A is a schematic front view of an electronic device according to an embodiment of the present application, and FIG. 10B is a schematic cross-sectional view of the electronic device shown in FIG. 10A . As shown in FIGS. 10A and 10B , the electronic device includes a display screen module and a casing 1030, wherein the display screen module includes a display screen 1010 and a fingerprint identification device 1020, and the display screen module can be the display screen module provided in the embodiment shown in FIG. 9 of this application.

Specifically, the display screen 1010 may be an OLED screen, or another screen with a relatively thin thickness, such as less than or equal to 3 mm, and which can transmit ultrasound. The fingerprint identification device 1020 is disposed below the fingerprint detection area 1011 of the display screen 1010 , and may be the fingerprint identification device provided in any one of the embodiments corresponding to FIGS. 2 to 8 of the present application.

Specifically, in this embodiment, reference may be made to the description of the fingerprint identification device and the display screen in the embodiments corresponding to FIGS. 2 to 8 . In this embodiment, the fingerprint identification device and the display screen will not be further described.

In some embodiments, the electronic device may be an electronic product or component such as a mobile phone, a tablet computer, a television, a notebook computer, a digital camera, a navigator, and a fingerprint lock.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present application. scope.

Claims (27)

1. A fingerprint identification device, characterized in that it includes: an ultrasonic generating device, an ultrasonic receiving device, and a signal processing module, the ultrasonic generating device includes a light source and a light-absorbing component, and the light-absorbing component and the ultrasonic receiving device are used for attaching to a display Below the screen, the light source is arranged on the side of the light absorbing member away from the display screen;

   Wherein, the light source is used to generate pulsed light; the light absorption component is used to absorb the pulsed light and generate an ultrasonic signal; the ultrasonic receiving device is used to receive the returned finger through the fingerprint detection area of the display screen. an echo signal of the ultrasonic signal, and converting the echo signal into a fingerprint electrical signal;

   The signal processing module is connected to the ultrasonic receiving device, and is used for receiving the fingerprint electrical signal and generating a fingerprint image according to the fingerprint electrical signal.
2. The fingerprint identification device according to claim 1, wherein the ultrasonic receiving device is a two-dimensional ultrasonic receiver array, and the two-dimensional ultrasonic receiver array is composed of a first preset number of ultrasonic receivers.
3. The fingerprint identification device according to claim 2, wherein the ultrasonic receiver is provided with a first electrode and a second electrode, and the first electrode and the second electrode are respectively provided on the ultrasonic receiver both sides of the piezoelectric material.
4. The fingerprint identification device according to claim 2 or 3, wherein the piezoelectric material of the ultrasonic receiver comprises AlN aluminum nitride material, modified aluminum nitride material, PVDF polyvinylidene fluoride material or zirconium titanic acid Lead film material.
5. The fingerprint identification device according to any one of claims 2 to 4, wherein the two-dimensional ultrasonic receiver array is in the shape of a square, the length of the square is at least 9 mm, and the width is at least 4 mm.
6. The fingerprint identification device according to any one of claims 1-5, wherein the ultrasonic generating devices are respectively provided on both sides of the ultrasonic receiving device.
7. The fingerprint identification device according to claim 6, wherein the ultrasonic receiving device is in the shape of a long strip, and the ultrasonic generating device is disposed on two sides corresponding to two long sides of the ultrasonic receiving device.
8. The fingerprint identification device according to any one of claims 1-7, wherein the light absorbing member is wedge-shaped or elongated.
9. The fingerprint identification device according to claim 1, wherein the light absorbing member comprises a slope for coupling with the light source, a connection surface for coupling with the display screen, and a connection between the slope and the display. The elevation between the connecting surfaces; the inclined surface and the connecting surface form a preset angle, and the preset angle is an acute angle.
10. The fingerprint identification device according to claim 1, wherein the light emitting surface of the light source is parallel to the display screen, and the light absorbing component comprises a plurality of Absorber components.
11. 11. The fingerprint identification device according to claim 10, wherein each of the sub-absorption components comprises a first connection surface for coupling with the display screen, a first inclined surface, and a first connection surface connected to the first inclined surface and the display screen. The first elevation between the first connection surfaces, the first inclined surface is at least partially coupled with the light source, the first connection surface and the first inclined surface form a preset angle, and the preset angle is an acute angle .
12. The fingerprint identification device according to any one of claims 8-11, wherein the length of the light source is half the length of the ultrasonic receiving device.
13. The fingerprint identification device according to claim 9 or 11, wherein the preset angle is determined by the thickness of the display screen, the size of the light absorbing member, the size of the ultrasonic receiving device, and the distance between the light source and the light source. The relative positional relationship of the ultrasonic receiving device is determined.
14. The fingerprint identification device according to claim 9 or 11, wherein the preset angle θ satisfies the following relational expression:

    L ₂ +L ₁ +dL/sinθ≥2h ₁ ×tanθ≥L ₁ +d

    Wherein, L ₂ is the length of the ultrasonic receiving device, L ₁ is the length of the second surface of the light absorbing member, L is the length of the light source, h ₁ is the thickness of the display screen, and d is the light absorption The distance between the component and the ultrasonic receiving device.
15. The fingerprint identification device according to claim 9 or 11, wherein the preset angle θ satisfies the following relational expression:

    h×(cotθ+tanθ)=L

    Wherein, L is the length of the light source, and h is the height of the light absorbing member.
16. The fingerprint identification device according to any one of claims 1-7, wherein the light absorbing member comprises a first surface coupled with the display screen and a second surface coupled with the light source, the first surface The surface is parallel to the second surface.
17. The fingerprint identification device according to any one of claims 1-7, wherein the light-absorbing component is attached to the lower part of the display screen through an ultrasonic coupling layer, and the light-absorbing component is coupled to the plane of the ultrasonic coupling layer. A groove is formed, and the ultrasonic coupling layer fills the groove to couple the light absorbing member with the display screen.
18. The fingerprint identification device according to any one of claims 1-7, wherein the light absorbing member comprises at least one strip-shaped groove, and the strip-shaped groove comprises two oppositely arranged side walls and an arc-shaped bottom surface .
19. The fingerprint identification device according to any one of claims 1-18, wherein the light source is a light emitting diode (LED) or a vertical cavity surface emitting laser (VCSEL).
20. The fingerprint identification device according to any one of claims 1-19, wherein the period of the pulsed light is 1 ns˜80 ns.
21. The fingerprint identification device according to any one of claims 1-20, wherein the light source is composed of a second preset number of LEDs, and the light source is in the shape of a long strip.
22. The fingerprint identification device according to any one of claims 1-21, wherein the light-absorbing material of the light-absorbing component is a black silica gel material.
23. The fingerprint identification device according to any one of claims 1-22, wherein the light-absorbing component comprises a third preset number of black light-absorbing lattices composed of black silica gel materials.
24. The fingerprint identification device according to any one of claims 1-23, wherein the number of the ultrasonic receiving devices is multiple, and each ultrasonic receiving device corresponds to a different fingerprint detection area; The device is provided with at least one of said ultrasonic generating devices.
25. The fingerprint identification device according to any one of claims 1-24, wherein the ultrasonic generating device further comprises a driving module, and the driving module is configured to provide a driving signal for the light source to control the generation of the light source the pulsed light.
26. A display screen module, characterized by comprising a display screen and the fingerprint identification device according to any one of claims 1-25.
27. An electronic device, characterized in that it comprises a casing and the display screen module of claim 26 .

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