CN210166797U - Ultrasonic fingerprint identification structure and electronic device - Google Patents

Abstract

The application relates to an ultrasonic fingerprint identification structure, which comprises an appearance layer, a backlight layer, an identification layer and a processing unit. The appearance layer comprises a protective cover plate and an ink layer attached to the inner side of the protective cover plate, and a hollow-out area is arranged on the ink layer. The processing unit is electrically connected with the backlight layer and the identification layer respectively, the identification layer is used for sensing the approach of fingers of a user, and the processing unit controls the backlight layer to light the hollowed-out area. And after the user finger further contacts the hollow area, the processing unit identifies the user identity based on the ultrasonic fingerprint image obtained by the ultrasonic identification layer. The ultrasonic fingerprint structure can not light the hollowed-out area in the dormant state, and the user only opens the lightening of the hollowed-out area after approaching, so that the hidden effect of the hollowed-out area can be realized.

Description

Ultrasonic fingerprint identification structure and electronic device

Technical Field

The present application relates to the field of electronic devices, and more particularly, to a concealable ultrasonic fingerprint recognition structure for indicating a fingerprint recognition area of a user, and an electronic device using the same.

Background

At present, electronic devices with an ultrasonic fingerprint identification function are increasing on the market. Ultrasonic fingerprint identification is widely applied due to the characteristics of good penetrability and high accuracy. However, in consideration of cost, the action area of ultrasonic fingerprint identification is mostly limited, and the electronic device usually needs to make an appearance mark in the action area of fingerprint identification to remind a user of a specific position of fingerprint identification, thereby ensuring the identification success rate and user experience. Common appearance marking methods at the present stage include blind hole forming, Ring forming, silk-screen Logo and the like. The appearance mark needs to be clearly distinguished from the rest of the appearance surface of the electronic device, and the appearance consistency of the electronic device is affected correspondingly.

SUMMERY OF THE UTILITY MODEL

The application provides an instruction ultrasonic fingerprint identification structure that can hide to promote the outward appearance uniformity that electronic product used behind the ultrasonic fingerprint identification. The technical scheme is as follows:

an ultrasonic fingerprint identification structure comprising:

the appearance layer comprises a protective cover plate and an ink layer attached to the inner side of the protective cover plate, and the ink layer is provided with a hollow-out area;

the backlight layer is arranged on one side, away from the protective cover plate, of the ink layer and is attached to the ink layer through optical cement, the backlight layer comprises a light guide plate and a light source arranged on the side edge of the light guide plate, and the light source is used for emitting light towards the light guide plate to light the hollowed-out area;

the identification layer is attached to the backlight layer through a light shading adhesive, and comprises a substrate, and a pixel identification layer, a piezoelectric layer and a capacitance induction layer which are sequentially stacked on one side of the substrate, which is far away from the appearance layer;

processing unit, respectively with the light source pixel identification layer and capacitance sensing layer electric connection, when the user finger is close to or contacts during the protection apron, capacitance sensing layer senses the electric capacity change to give with the sensing signal processing unit, processing unit controls respectively the light source is luminous, and passes through pixel identification layer encourages the piezoelectric layer sends the ultrasonic wave, the ultrasonic wave passes behind the ultrasonic wave fingerprint identification structure through user's finger reflection, pixel identification layer is used for receiving the reflection back the ultrasonic wave forms fingerprint signal and returns processing unit, processing unit will fingerprint signal discerns the authentication to user's fingerprint after converting into the fingerprint image.

This application ultrasonic wave fingerprint identification structure is through range upon range of in proper order the outward appearance layer the backlight layer with the discernment layer makes the protection, provides the function of being shaded and ultrasonic identification respectively the line. Wherein the ink layer in the appearance layer can hide the backlight layer and the identification layer. The identification layer senses the approaching action of a finger of a user through the capacitance sensing layer and controls the backlight layer to be lightened through the processing unit, so that the hollowed-out area of the ink layer is lightened. The hollow area of lighting can instruct user's ultrasonic fingerprint identification's effect region, is convenient for be used for pressing and passes through the fingerprint identification function is realized to the discernment layer. This application ultrasonic wave fingerprint identification structure utilizes the ultrasonic wave can pierce through the characteristic on printing ink layer, has realized can hiding the instruction regional to fingerprint identification when not needing, only just when the user uses the fingerprint identification function to being used for carrying out regional instruction, has guaranteed electron device's outward appearance uniformity, promotes user experience.

The processing unit comprises a driving module, the driving module is electrically connected with the piezoelectric layer through the pixel identification layer, the driving module is used for sending a sinusoidal signal to the pixel identification layer to excite the piezoelectric layer to send out ultrasonic waves, and the driving module is further used for receiving the fingerprint signal and converting the fingerprint signal into a fingerprint image. The driving module utilizes the advantage of high resolution of the pixel identification layer to provide the necessary sinusoidal signal of the piezoelectric layer and achieve an effective ultrasonic wave generation function.

The driving module is electrically connected with the capacitance sensing layer and is used for receiving the sensing signal sent by the capacitance sensing layer. The ultrasonic excitation and capacitance induction functions are simultaneously arranged on the driving module, so that the integration level of the driving module can be improved.

The ultrasonic fingerprint identification structure further comprises a flexible circuit board and an anisotropic conductive adhesive, and the driving module is electrically connected with the pixel identification layer and the capacitance induction layer respectively through the flexible circuit board and the anisotropic conductive adhesive. By utilizing the anisotropic conductive adhesive, a better electric connection effect can be realized.

The processing unit further comprises a light source control module, the light source control module is electrically connected with the driving module, and the driving module is used for sending a starting signal to the light source control module after receiving the sensing signal so that the light source control module controls the light source to emit light. The light source control module can be used for more accurately controlling the light emission of the light source.

The light source control module controls the light source to have a first brightness and a second brightness, and when the processing unit receives the sensing signal, the light source control module controls the light source to have the first brightness;

when the processing unit successfully identifies the user fingerprint, the light source control module controls the light source to have a second brightness. Grading the brightness of the light source can provide visual feedback of whether the user fingerprint identification is successful.

The processing unit further comprises a fingerprint matching module and a memory, the fingerprint matching module is electrically connected with the memory, at least one user fingerprint image is prestored in the memory, the fingerprint matching module is electrically connected with the driving module, and the fingerprint matching module is used for matching and judging the fingerprint image and the at least one user fingerprint image in the memory after the fingerprint image is converted by the driving module. One or more user fingerprint images can be prestored in the memory for comparison and identification.

The identification layer is arranged right opposite to the hollow area in the stacking direction of the appearance layer, the backlight layer and the identification layer, so that when a finger of a user contacts the area, right opposite to the hollow area, of the protection cover plate, the identification layer can achieve a fingerprint identification function. The hollowed-out area may be used to indicate an effective ultrasonic fingerprint identification area for a user.

And a chip attaching film is further arranged on one side, away from the piezoelectric layer, of the capacitance sensing layer and is used for reflecting the ultrasonic waves emitted by the piezoelectric layer so that the ultrasonic waves are transmitted towards the direction of the protective cover plate.

Wherein the ultrasonic wave emitted by the piezoelectric layer has a first wavelength λ, and the thickness of the pixel identification layer is λ/2, so that the pixel identification layer forms resonance when exciting the piezoelectric layer. The resonant ultrasonic waves can form a clearer fingerprint image after being reflected.

And a shading film is arranged between the shading glue and the light guide plate and is bonded with the light guide plate to shade light rays in the backlight layer and prevent the light rays from leaking to the pixel identification layer. Because of the good penetrability of ultrasonic waves, the function of fingerprint identification cannot be influenced by the increase of the light shielding film.

The application also relates to an electronic device which comprises a display area, wherein the position, close to one side edge of the display area, of the display area is provided with the ultrasonic fingerprint identification structure. The electronic device is provided with the ultrasonic fingerprint identification structure, so that the appearance consistency of the electronic device is improved.

The protective cover plate is also used for covering the display area at the same time, and the backlight layer is also used for providing a backlight source for the display area at the same time. The protective cover plate, the backlight layer and the display area of the electronic device are shared, so that the internal structure of the electronic device can be simplified, and the cost is saved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings used in the description of the embodiments of the present application will be briefly described below.

FIG. 1 is a cross-sectional view of an ultrasonic fingerprint identification structure provided in an embodiment of the present application;

FIG. 2 is a schematic diagram of an internal frame of an ultrasonic fingerprint identification structure according to an embodiment of the present application;

fig. 3 is a schematic view of an electronic device according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Please refer to fig. 1, which illustrates an ultrasonic fingerprint identification structure 100 according to the present application, which is disposed in an electronic device 200 (see fig. 3) to implement a fingerprint identification function. The ultrasonic fingerprint recognition structure 100 includes an appearance layer 10, a backlight layer 20, and a recognition layer 30, which are sequentially stacked, and a processing unit 40 disposed inside the electronic device 200. The appearance layer 10 includes a protective cover 11 and an ink layer 12 attached to the inner side of the protective cover 11. The protection cover plate 11 may be made of glass, PET, PC, or the like, and is used to realize the sealing and protecting functions of the ultrasonic fingerprint identification structure 100. The ink layer 12 is provided with a hollowed-out area 121. The backlight layer 20 is disposed on a side of the ink layer 12 away from the protective cover plate 11, and the backlight layer 20 is attached to the ink layer 12 through an optical adhesive 50. Optical Adhesive 50 is mostly implemented by OCA (Optical Clear Adhesive), and Optical Adhesive 50 can transmit light in addition to bonding backlight layer 20 and ink layer 12. The backlight layer 20 includes a light guide plate 21 and a light source 22 disposed at one side of the light guide plate 21. The light source 22 is disposed opposite to the side of the light guide plate 21, the light source 22 is configured to emit light toward the light guide plate 21, and the light is sufficiently diffused in the light guide plate 21, so that the light guide plate 21 is entirely in a luminous state. The lighted light guide plate 21 cannot be observed from the outside due to the blocking of the ink layer 12, but the hollow-out area 121 in the ink layer 12 does not contain ink for blocking light, so that the hollow-out area 121 can transmit the brightness of the light guide plate 21, and a user can observe that the hollow-out area 121 is in a lighting state from the outside. By providing the hollow-out area 121 as a key or a LOGO or the like of the electronic device 200, the lighted hollow-out area 121 can be made more noticeable and easily recognizable under the dark ink layer 12.

The identification layer 30 is attached to the backlight layer 20 by a light blocking adhesive 60. Masking adhesive 60 may be implemented using PSA (pressure sensitive adhesive). The identification layer 30 is also a laminated structure, and includes a substrate 31, and a pixel identification layer 32, a piezoelectric layer 33, and a capacitance sensing layer 34 laminated in this order on the side of the substrate 31 away from the appearance layer 10. Referring to fig. 2, the processing unit 40 is electrically connected to the light source 22, the pixel identification layer 32 and the capacitance sensing layer 34, respectively. The pixel identification layer 32 is implemented by using a TFT, the piezoelectric layer 33 is implemented by using a piezoelectric material, such as piezoelectric ceramic, a polyvinylidene fluoride copolymer film P (VDF-TrFE), and the capacitance sensing layer 34 can be implemented by using a material such as Ag. When a user's finger approaches or touches the protective cover 11, the capacitance sensing layer 34 senses the capacitance change of the surface and generates a sensing signal to be transmitted to the processing unit 40. The processing unit 40 controls the light sources 22 to emit light and excites the piezoelectric layer 33 to emit ultrasonic waves through the pixel recognition layer 32, respectively. The light source 22 emits light to illuminate the hollow area 121, and the ultrasonic waves emitted by the piezoelectric layer 33 can reach the user's finger after passing through the ultrasonic fingerprint identification structure 100. The principle of ultrasonic fingerprint collection is to utilize the ability of ultrasonic waves to penetrate through materials and to generate reflected waves with different sizes along with the different materials. That is, when the ultrasonic wave reaches the surface of a different material, the degree of absorption, penetration and reflection is different. Therefore, the positions of fingerprint ridges and valley can be distinguished by using the difference of acoustic impedances when the ultrasonic wave propagates through the fingerprint ridges (skin) and the fingerprint valley (air). Utilize the stronger penetrability of ultrasonic wave, make it pass light guide plate and printing ink layer, can get back to pixel identification layer 32 through the reflection of finger, collect fingerprint signal through the TFT of pixel identification layer 32, pixel identification layer 32 sends fingerprint signal for processing unit 40 again, and processing unit 40 can turn into fingerprint image with fingerprint signal, and then reaches the function of carrying out the fingerprint identification authentication to user's identity.

The ultrasonic fingerprint identification structure 100 of the present application protects, provides backlight and ultrasonic identification functions by the appearance layer 10, the backlight layer 20 and the identification layer 30, which are sequentially stacked. The appearance layer 10 can hide the backlight layer 20 and the identification layer 30 due to the arrangement of the ink layer 12, and the appearance consistency of the electronic device can be ensured when the fingerprint identification work is not started. After the finger of the user approaches the ultrasonic fingerprint identification structure 100, the identification layer 30 can capture the capacitance change through the capacitance sensing layer 34, and control the backlight layer 20 to be turned on through the processing unit 40, so that the hollow area 121 of the ink layer 22 is displayed and prompts the user of the effective identification area of the current fingerprint. Further, the processing unit 40 also excites the piezoelectric layer 33 to emit ultrasonic waves through the pixel identification layer 32, so as to perform fingerprint identification on a finger of a user contacting the protective cover 11. This application ultrasonic wave fingerprint identification structure 100 utilizes the ultrasonic wave can pierce through the characteristic of printing ink layer 12 and light guide plate 21, has realized can hiding the instruction to the fingerprint identification region when not needing, just carries out the effect of instructing to the identification region when the user launches the fingerprint identification function, has guaranteed electron device 200's outward appearance uniformity, promotes user experience.

In one embodiment, the processing unit 40 comprises a driver module 41, i.e. an ASIC. The driving module 41 is electrically connected to the pixel identification layer 32. After the processing unit 40 receives the sensing signal from the capacitance sensing layer 34, the driving module 41 is configured to send a sinusoidal signal to the pixel identification layer 32, and excite the piezoelectric layer 33 to emit an ultrasonic wave through the pixel identification layer 32. By taking advantage of the high TFT resolution of the pixel identification layer 32, a sinusoidal signal of the precision required for fingerprint identification can be supplied to the piezoelectric layer 33 to generate ultrasonic waves with effective precision. After the pixel identification layer 32 receives the reflected ultrasonic fingerprint signal, the pixel identification layer 32 in the TFT mode also provides a high-precision fingerprint signal for the driving module 41, so that the driving module 41 can convert the fingerprint image.

In one embodiment, the driving module 41 is further electrically connected to the capacitance sensing layer 34. The driving module 41 is configured to receive a sensing signal from the capacitive sensing layer 34. The ultrasonic excitation, ultrasonic image conversion, and capacitance sensing functions are all provided on the driving module 41, so that the integration level of the driving module 41 can be improved.

In an embodiment, the driving module 41 may be disposed on a side of the substrate 31 away from the backlight layer 20, and the ultrasonic fingerprint identification structure 100 further includes a flexible circuit board 70 and an anisotropic conductive adhesive 80. By using the unidirectional conductive property of the anisotropic conductive adhesive 80, the driving module 41 is electrically connected to the pixel identification layer 32 through the flexible circuit board 70 and the anisotropic conductive adhesive 80, and is electrically connected to the capacitance sensing layer 34 through the flexible circuit board 70 and the anisotropic conductive adhesive 80. The flexible circuit board 70 and the anisotropic conductive adhesive 80 have high reliability in the aspect of realizing the electrical connection of the multi-gate line, and have wide application in the existing electronic devices.

In one embodiment, the processing unit 40 further includes a light source control module 42. The light source control module 42 is electrically connected to the driving module 41, and the light source control module 42 is used for controlling the light source 22 to emit light. When the driving module 41 receives the sensing signal from the capacitive sensing layer 34, the driving module 41 sends a start signal to the light source control module 42, so that the light source control module 42 controls the light source 22 to emit light, and further the hollow area 121 is lighted.

Further, the light source control module 42 may further enable the light source 22 to emit light with different first and second luminances by means of light emitting timing, or selectively controlling the number of light emitting units in the light source 22. When the processing unit 40 (usually, the driving module 41) receives the sensing signal, the light source control module 42 controls the light source to emit light at a first brightness; when the processing unit 40 succeeds in recognizing the user fingerprint, the light source control module 42 controls the light source 22 to emit light at the second brightness. The second luminance may be further set higher than the first luminance. Therefore, the brightness of the light source 22 is graded, and when a user performs fingerprint identification, the user can be guided to place a finger in the action area of the ultrasonic waves only by lightening the hollow-out area 121. When the user identity is successfully authenticated, the brightness of the light source 22 is increased, so that the brightness required by the user to observe the electronic device 200 can be provided, and the display function is realized. The brightness grading setting of the light source control module 42 may provide visual feedback to the user whether the fingerprint recognition was successful.

In one embodiment, the processing unit 40 further includes a fingerprint matching module 43 and a memory 44 electrically connected thereto. At least one user fingerprint image is prestored in the memory 44, the fingerprint matching module 43 is electrically connected with the driving module 41, and the fingerprint matching module 43 is used for matching and judging the fingerprint image and the at least one user fingerprint image in the memory 44 one by one after the fingerprint image obtained by conversion of the driving module 41 is connected, so that the identity of the user is identified. It is understood that when the fingerprint image obtained by the driving module 41 is successfully matched with any one of the fingerprint images of the user in the memory 44, the fingerprint matching module 43 determines that the user passes the identification, and the electronic device 200 can be unlocked and used by the user. The memory 44 may be a storage unit provided separately from the ultrasonic fingerprint recognition structure 100 of the present application, or may be a storage unit of the electronic apparatus 200 to store a user fingerprint image.

In one embodiment, the appearance layer 10, the backlight layer 20, and the identification layer 30 are stacked along the first direction 001, and the identification layer 30 is disposed opposite to the hollow 121 in the first direction 001. In order to reduce the volume of the ultrasonic fingerprinting structure 100 of the present application, the piezoelectric layer 33 preferably sends ultrasonic waves vertically upwards, so that the ultrasonic waves can be received by the pixel identification layer 32 after being reflected vertically. Because the hollow-out area 121 is used for instructing the scope of action of user's ultrasonic fingerprint identification, when the transmission and the reflection of ultrasonic wave all transmit along vertical direction, can reduce the volume of this application ultrasonic fingerprint identification structure 100.

In one embodiment, a chip attach film 35 is further disposed on a side of the capacitance sensing layer 34 away from the piezoelectric layer 33. The die attach film 35 is typically a daf (die attach film) die attach film 35 attached to the capacitance sensing layer 34. Since the piezoelectric layer 33 generates ultrasonic waves by vibration, the transmission direction of the ultrasonic waves thereof exists in both the forward direction and the reverse direction of the first direction 001. I.e. part of the ultrasonic waves will be emitted towards the capacitance-sensing layer 34. In order to improve the efficiency of the ultrasonic wave emission from the piezoelectric layer 33, the chip attach film may be configured to reflect the ultrasonic wave emitted from the piezoelectric layer 33, so that the ultrasonic wave emitted toward the capacitance sensing layer 34 is diverted and transmitted toward the protective cover 11.

In one embodiment, the ultrasonic waves emitted by the piezoelectric layer 33 have a fixed first wavelength λ. The thickness of the pixel identification layer 32 is set to be lambda/2, so that resonance can be formed when the pixel identification layer 32 excites the piezoelectric layer 33 based on a sine signal, the amplitude of ultrasonic waves formed after resonance is larger, and a clearer fingerprint image can be formed after reflection.

In one embodiment, when the identification layer 30 is in operation, the TFT structure of the pixel identification layer 32, including the piezoelectric layer 33 and the capacitance sensing layer 34, are in a high-precision operation state, and it is necessary to avoid interference factors, such as light, in the operation environment as much as possible. The light shielding effect of the light guide plate 21 by the light shielding glue 60, which is usually implemented in a PSA manner, may be lost, so that a part of light of the light guide plate 21 enters the identification layer 30 to interfere with fingerprint identification. Therefore, a light shielding film 90 is further provided between the light shielding adhesive 60 and the light guide plate 21. The light shielding film 90 is adhered to the light guide plate 21 to shield the light in the backlight layer 20 and prevent the light from leaking to the identification layer 30. And because the ultrasonic wave is good penetrability, the function of ultrasonic fingerprint identification can not be influenced by the increase of the shading film 90.

Fig. 3 is an electronic device 200 according to the present application, which includes a display area 201. The ultrasonic fingerprint recognition structure 100 is disposed at a position of the display area 201 near one side thereof. The ultrasonic fingerprint identification structure 100 is observed from the appearance of the electronic device 200, and is integrated with the black ink area around the display 201, and the hollow area 121 cannot be prominently displayed when the backlight layer 20 does not emit light, so that the electronic device 200 is assembled with the ultrasonic fingerprint identification structure 100, and the appearance consistency of the electronic device 200 is ensured while the fingerprint identification function is realized. And when the user's finger is close to protection apron 11, this application ultrasonic fingerprint identification structure 100 can sense user's operation of being close through the capacitance variation, lights fretwork area 121 again and realizes the guide of fingerprint identification effective area to the user.

In one embodiment, the protective cover 11 is also used to cover the display area 201, and the backlight layer 20 is also used to provide backlight for the display area 201. That is, the protective cover 11 and the backlight layer 20 of the ultrasonic fingerprint identification structure 100 of the present application can be manufactured synchronously with the display area 201 of the electronic device 200, so as to share the protective cover 11 and the backlight layer 20 with the display area of the electronic device 200, thereby simplifying the internal structure of the electronic device 200 and saving the cost.

The above-described embodiments do not limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the above-described embodiments should be included in the protection scope of the technical solution.

Claims (13)

1. An ultrasonic fingerprint identification structure, comprising:

the appearance layer comprises a protective cover plate and an ink layer attached to the inner side of the protective cover plate, and the ink layer is provided with a hollow-out area;

the backlight layer is arranged on one side, away from the protective cover plate, of the ink layer and is attached to the ink layer through optical cement, the backlight layer comprises a light guide plate and a light source arranged on the side edge of the light guide plate, and the light source is used for emitting light towards the light guide plate to light the hollowed-out area;

the identification layer is attached to the backlight layer through a light shading adhesive, and comprises a substrate, and a pixel identification layer, a piezoelectric layer and a capacitance induction layer which are sequentially stacked on one side of the substrate, which is far away from the appearance layer;

processing unit, respectively with the light source pixel identification layer and electric capacity response layer electric connection, electric capacity response layer is used for the user finger to be close to or contact response electric capacity changes during the protection apron to transmit sensing signal for processing unit, processing unit is used for control the light source is luminous, and passes through pixel identification layer encourages the piezoelectric layer sends the ultrasonic wave, so that the ultrasonic wave passes behind the ultrasonic wave fingerprint identification structure through user's finger reflection, pixel identification layer is used for receiving the reflection return the ultrasonic wave is in order to form fingerprint signal and pass back processing unit, processing unit still be used for with fingerprint signal carries out the discernment authentication to user's fingerprint after converting into the fingerprint image.

2. The ultrasonic fingerprint identification structure of claim 1, wherein the processing unit comprises a driving module, the driving module is electrically connected to the piezoelectric layer through the pixel identification layer, the driving module is configured to send a sinusoidal signal to the pixel identification layer to excite the piezoelectric layer to emit an ultrasonic wave, and the driving module is further configured to receive the fingerprint signal and convert the fingerprint signal into a fingerprint image.

3. The ultrasonic fingerprint identification structure of claim 2, wherein the driving module is further electrically connected to the capacitive sensing layer, and the driving module is configured to receive the sensing signal sent by the capacitive sensing layer.

4. The ultrasonic fingerprint identification structure of claim 3, further comprising a flexible circuit board and an anisotropic conductive adhesive, wherein the driving module is electrically connected to the pixel identification layer and the capacitive sensing layer through the flexible circuit board and the anisotropic conductive adhesive, respectively.

5. The ultrasonic fingerprint identification structure of claim 2, wherein the processing unit further comprises a light source control module, the light source control module is electrically connected to the driving module, and the driving module is configured to send a start signal to the light source control module after receiving the sensing signal, so that the light source control module controls the light source to emit light.

6. The ultrasonic fingerprint identification structure of claim 5, wherein the light source control module is configured to control the light source to have a first brightness when the processing unit receives the sensing signal;

the light source control module is used for controlling the light source to have second brightness when the processing unit successfully identifies the user fingerprint.

7. The ultrasonic fingerprint identification structure of claim 2, wherein the processing unit further comprises a fingerprint matching module and a memory, the fingerprint matching module and the memory are electrically connected, at least one user fingerprint image is prestored in the memory, the fingerprint matching module is electrically connected with the driving module, and the fingerprint matching module is configured to perform matching determination on the fingerprint image and the at least one user fingerprint image in the memory after receiving the fingerprint image converted by the driving module.

8. The ultrasonic fingerprint identification structure according to any one of claims 1 to 7, wherein the identification layer is disposed opposite to the hollow area in a stacking direction of the appearance layer, the backlight layer and the identification layer, so that when a finger of a user contacts an area of the protective cover plate opposite to the hollow area, the identification layer can realize a fingerprint identification function.

9. The ultrasonic fingerprint identification structure of claim 8, wherein a chip attachment film is further disposed on a side of the capacitance sensing layer away from the piezoelectric layer, and the chip attachment film is configured to reflect the ultrasonic waves emitted from the piezoelectric layer so that the ultrasonic waves are transmitted toward the protective cover.

10. The ultrasonic fingerprinting structure of claim 8, wherein the ultrasonic wave emitted by the piezoelectric layer has a first wavelength λ and the pixel identification layer has a thickness λ/2 such that the pixel identification layer resonates when it excites the piezoelectric layer.

11. The ultrasonic fingerprint identification structure of claim 8, wherein a light shielding film is further disposed between the light shielding glue and the light guide plate, and the light shielding film is bonded to the light guide plate to shield light in the backlight layer and prevent light from leaking to the pixel identification layer.

12. An electronic device, comprising a display area, wherein the display area is provided with the ultrasonic fingerprint identification structure according to any one of claims 1 to 11 near a side edge of the display area.

13. The electronic device of claim 12, wherein the protective cover sheet is further configured to simultaneously cover the display area, and wherein the backlight layer is further configured to simultaneously provide a backlight for the display area.

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