Under-screen fingerprint recognition circuit and its stacked structure, display panel, and fingerprint acquisition method

Abstract

An under-screen fingerprint recognition circuit, a stacked structure, a display panel, and a fingerprint acquisition method. The under-screen fingerprint recognition circuit includes a drain of a first transistor connected to a display data receiving end, a display driving signal output end and a start fingerprint recognition end commonly connected to a gate of the first transistor, a source of the first transistor connected to an optical fingerprint sensor, the optical fingerprint sensor connected to a common ground end, a gate of a second transistor connected to the first transistor, a source of the second transistor connected to a third transistor, a drain of the second transistor connected to a working voltage end, a gate of the third transistor connected to a fingerprint recognition selection end, a source of the third transistor connected to a recognition output end, a first capacitor and a second capacitor connected in parallel to the optical fingerprint sensor, such that the first transistor receives a display driving signal or resets a fingerprint recognition signal, and can output a display driving signal or perform fingerprint recognition. It also includes a stacked structure, a display panel, and a fingerprint acquisition method designed according to this under-screen fingerprint recognition circuit.

Description

Technical Field

[0001] The present invention relates to under-screen fingerprint recognition, and particularly to an under-screen fingerprint recognition circuit, a stacked structure matching the under-screen fingerprint recognition circuit, a display panel having the stacked structure, and a fingerprint acquisition method for the display panel. Background Art

[0002] In recent years, the fingerprint recognition function has become a standard feature of smart electronic products. In the case of early capacitive fingerprint recognition, a sensor is composed of many tiny capacitor arrays. When a user touches the sensor with a finger, the raised parts of the fingerprint on the finger will contact the capacitors, while the recessed parts will not. In this way, a capacitance difference will be generated, and then the fingerprint can be depicted. However, since the capacitive fingerprint recognition sensor occupies a part of the surface of smart electronic products, with the recent design trend of smart electronic products towards full-screen designs, the capacitive fingerprint recognition sensor has gradually disappeared in smart electronic products.

[0003] As an alternative technical solution, currently there are mainly two under-screen fingerprint recognition technologies, namely, combining an optical fingerprint recognition structure in the liquid crystal screen stack of smart electronic products (hereinafter referred to as optical under-screen fingerprint recognition technology), or combining an ultrasonic fingerprint recognition structure in the liquid crystal screen stack structure. In the case of optical under-screen fingerprint recognition technology, the equivalent optical fingerprint recognition sensing circuit 11 and the equivalent driving circuit 12 of each pixel 10 in the fingerprint recognition area of the liquid crystal screen are two separate and unconnected circuits (as Figure 1 shown). The common equivalent optical fingerprint recognition sensing circuit 11 is a 3T1C circuit (as Figure 2 shown), and the equivalent driving circuit 12 is a 1T1C circuit (as Figure 3 shown) or a 2T1C circuit.

[0004] Please refer to Figure 4As shown, the liquid crystal screen stack structure 13 of the optical in-screen fingerprint recognition technology includes a display area 130, a touch area 131, a fingerprint recognition area 132, etc. Metal vias 133 are provided in the display area 130, the touch area 131, and the fingerprint recognition area 132 to connect different layers, so as to implement the equivalent optical fingerprint recognition sensing circuit 11 and the equivalent driving circuit 12. In addition, the optical fingerprint recognizer 1320 in the fingerprint recognition area 132 is buried deep in the middle of the liquid crystal screen stack structure 13, making the optical fingerprint recognizer 1320 far from the surface of the liquid crystal screen, which will affect the recognition efficiency of the optical fingerprint recognizer 1320. Also, the display area 130, the touch area 131, and the fingerprint recognition area 132 all require a transparent conductive layer 134. The transparent conductive layer 134 is usually indium tin oxide (ITO for short). However, as can be seen from the figure, the position of the transparent conductive layer 134 in the fingerprint recognition area 132 is completely different from that in the display area 130 and the touch area 131, so that the equivalent fingerprint recognition sensing circuit 11 that needs to be fabricated in the fingerprint recognition area 132 requires additional processes.

[0005] In summary, since the equivalent driving circuit 12 and the equivalent optical fingerprint recognition sensing circuit 11 are two independent and unconnected circuits, a lot of space is required in the liquid crystal screen stack structure 13 to fabricate the equivalent electronic components required for the equivalent circuits, resulting in a reduction in the aperture ratio of the liquid crystal screen stack structure 13 and affecting the overall light-emitting efficiency. Moreover, the position of the transparent conductive layer 134 in the fingerprint recognition area 132 is completely different from that in the display area 130 and the touch area 130, making the manufacturing process of the traditional optical in-screen fingerprint recognition technology more complex and reducing the production yield. Therefore, how to improve the equivalent driving circuit and the equivalent optical fingerprint recognition sensing circuit of the optical in-screen fingerprint recognition technology, thereby increasing the aperture ratio, and improving the liquid crystal screen stack structure and reducing the complex manufacturing process will be an urgent problem to be solved. Summary of the Invention

[0006] In view of the problems of the prior art, one object of the present invention is to integrate a traditional equivalent driving circuit and an equivalent optical fingerprint recognition sensing circuit. By reducing the structure of equivalent electronic components required to fabricate the equivalent circuit in a stacked structure, the aperture ratio is increased and the overall luminous efficiency is improved. Another object of the present invention is to dispose the fingerprint recognition area at a position close to the display area and the touch area, so that the transparent conductive layer does not need to be fabricated multiple times in the liquid crystal screen stacked structure, thereby simplifying the manufacturing process, reducing the manufacturing time, and further reducing the manufacturing cost. Yet another object of the present invention is to fabricate a display panel with the aforementioned stacked structure. Since the traditional fingerprint recognition operation method is not applicable after the integration of the equivalent driving circuit and the equivalent optical fingerprint recognition sensing circuit, another object of the present invention is to perform a fingerprint acquisition method on the aforementioned display panel with a new operation process.

[0007] According to one object of the present invention, there is provided an under-screen fingerprint recognition circuit, including a first transistor, a second transistor, a third transistor, a first capacitor, a second capacitor, and an optical fingerprint sensor. The drain of the first transistor is connected to a display data receiving terminal, the gate of the first transistor is connected to a data output terminal and a reset fingerprint information terminal, for receiving a display driving signal from the data output terminal or a reset fingerprint recognition signal from the reset fingerprint information terminal. The source of the first transistor is connected to the optical fingerprint sensor, and then connected to a common ground terminal from the optical fingerprint sensor. The optical fingerprint sensor is connected in parallel with the first capacitor, and the second capacitor is connected in parallel between the optical fingerprint sensor and the first capacitor. The gate of the second transistor is connected between the source of the first transistor and the optical fingerprint sensor. The drain of the second transistor is connected to a working voltage terminal, and the source of the second transistor is connected to the drain of the third transistor. The gate of the third transistor is connected to a fingerprint recognition selection terminal for receiving a fingerprint recognition signal, and the source of the third transistor is connected to a recognition output terminal.

[0008] Wherein, when the first transistor receives a reset fingerprint recognition signal from the reset fingerprint information terminal, it is in the recognition mode, and when the first transistor does not receive a reset fingerprint recognition signal, it is in the display mode. In the recognition mode, a reset stage, an exposure stage, and a drawing stage are sequentially performed. During the reset stage, the first transistor receives a reset fingerprint recognition signal from the reset fingerprint information terminal, turns on the first transistor, the second transistor, and the third transistor, and releases the parasitic capacitance in the circuits of the second transistor and the third transistor. During the exposure stage, the first transistor and the second transistor are turned on and the third transistor is turned off, and the display driving signal is first stored in the first capacitor, and the optical fingerprint sensor is activated. In the drawing stage, the first transistor is turned off and the third transistor is turned on, and the opening amplitude of the second capacitor is controlled according to the fingerprint pattern sensed by the optical fingerprint sensor, and different magnitudes of working voltages are output from the recognition output terminal. At the same time, the display driving signal in the first capacitor is transmitted to the display data receiving terminal.

[0009] Among them, in the display mode of the under-screen fingerprint recognition circuit, the first transistor and the second transistor are turned on, while the third transistor is turned off. The gate of the first transistor receives a display driving signal from the data output terminal and transmits the display driving signal to the display data receiving terminal. Although the second transistor is in the on state, the third transistor is turned off, and the working voltage cannot be output.

[0010] Among them, the first capacitor is an energy storage capacitor, and the second capacitor stabilizes the operation of the optical fingerprint sensor.

[0011] According to another object of the present invention, there is provided an under-screen fingerprint recognition stacked structure, including a substrate, a first unit, and a second unit. The substrate, the first unit, and the second unit are stacked in sequence from bottom to top. A plurality of pixel regions are jointly defined between the substrate, the first unit, and the second unit. At least a display sub-region and a recognition sub-region are defined in a part of the pixel regions. The display component is disposed at a position of the first unit corresponding to the display sub-region, and the optical fingerprint sensor is disposed at a position of the second unit corresponding to the display sub-region. An equivalent under-screen fingerprint recognition circuit is formed between the first unit and the second unit, and the display component and the optical fingerprint sensor are connected to the equivalent under-screen fingerprint recognition circuit in the second unit.

[0012] Among them, the first unit includes a buffer layer, a gate insulating layer, an interlayer dielectric layer (ILD for short), and a planarization layer stacked in sequence from bottom to top. A shielding metal is provided at the projection position of the substrate in the display sub-region. The buffer layer is disposed on the substrate and covers the shielding metal. Above the buffer layer, there are provided drain semiconductor components and source semiconductor components for the first transistor, the second transistor, and the third transistor, as well as a polysilicon component for separating the drain semiconductor component and the source semiconductor component. The gate insulating layer covers the drain semiconductor component, the source semiconductor component, and the polysilicon component. The gate semiconductor components and the first metal region of the first transistor, the second transistor, and the third transistor are disposed above the gate insulating layer, and the gate of the first transistor is shielded by the shielding metal. The gate semiconductor component and the first metal region are either not connected or connected according to requirements in the gate insulating layer. The interlayer dielectric layer (ILD for short) covers the gate semiconductor component and the first metal region. A plurality of second metal regions are provided on the interlayer dielectric layer, and each second metal region is either not connected or connected according to requirements in the interlayer dielectric layer. The planarization layer covers each second metal region.

[0013] Among them, the second unit includes a first insulating layer, a second insulating layer, and a third insulating layer stacked in sequence from bottom to top. A plurality of third metal regions are provided on the surface of the first insulating layer, and each of the third metal regions is either non - communicating or communicating on the first insulating layer according to design requirements. A common electrode is provided on the surface of the second insulating layer at positions corresponding to the display sub - region and the identification sub - region. A first electrode is provided on the surface of the third insulating layer at the projection position corresponding to the display sub - region, and a second electrode is provided on the surface of the third insulating layer at the projection position corresponding to the identification sub - region. A display component is disposed between the first electrode and the common electrode within the second insulating layer, and the display component is excited by the first electrode and the common electrode according to a display driving signal. An optical fingerprint sensor is disposed between the second electrode and the common electrode within the second insulating layer. Moreover, one of the first electrodes extends beyond the projection position of the display sub - region and is sequentially connected to the third metal region, the second metal region, and the drain semiconductor component via a metal through - hole provided in the underlying stacked structure. Additionally, the second electrode is sequentially connected to the underlying third metal region, the second metal region, and the first metal region through a metal through - hole provided below it.

[0014] Among them, at the projection position corresponding to the identification sub - region on the surface of the third insulating layer, one of the third metal regions shields the optical fingerprint sensor.

[0015] Among them, each pixel region includes a touch sub - region, and a touch circuit is disposed within the touch sub - region of the second unit.

[0016] According to yet another object of the present invention, a display panel is provided, which includes a picture output area and a fingerprint identification area. Among them, the fingerprint identification area is the aforementioned under - screen fingerprint identification stacked structure, and the difference between the picture output area and the fingerprint identification area is that the picture output area only has a display sub - region, and the fingerprint identification area is located within the picture output area, or the picture output area occupies a part of the display panel, while the fingerprint identification area occupies a part of the display panel.

[0017] According to still another object of the present invention, a fingerprint acquisition method for under - screen fingerprint identification is provided, which is applied to a display panel. The display panel is the aforementioned fingerprint identification area. The fingerprint identification area repeatedly performs the following steps during the display period and the identification period. During the display period, the display sub - region and the touch sub - region output a plurality of display pictures according to the display driving signal and simultaneously perform touch sensing. During the identification and display period, it is output in a reset stage, an exposure stage, and a drawing stage. In the reset stage, the display sub - region outputs a display picture according to the display driving signal, and at the same time, the identification sub - region is reset. In the exposure stage, the display sub - region maintains the display picture of the reset stage, and the identification sub - region uses the light source of the display picture of the display sub - region as the exposure light source for fingerprint identification. In the drawing stage, the display sub - region maintains the display picture of the reset stage, and the identification sub - region starts to draw a fingerprint pattern.

[0018] Among them, the reset stage, the exposure stage, and the rendering stage are respectively carried out within the time of outputting one frame of the picture.

[0019] As described above, the present invention integrates the traditional equivalent driving circuit and the equivalent optical fingerprint recognition sensing circuit, so that the under-screen fingerprint recognition laminated structure made according to the equivalent circuit has an increased aperture ratio of the under-screen fingerprint recognition laminated structure due to the reduction of electronic components in the equivalent circuit, achieving the purpose of improving the overall luminous efficiency, and can also simplify the production, reduce the manufacturing time, and further achieve the purpose of reducing the production cost. Moreover, the fingerprint acquisition method for under-screen fingerprint recognition can maintain the output of the picture, can also perform fingerprint recognition simultaneously, and can even be used as a touch panel. Description of the Drawings

[0020] Figure 1 Schematic diagram of the equivalent driving circuit and the equivalent optical fingerprint recognition sensing circuit of one pixel in the fingerprint recognition area of a traditional liquid crystal screen;

[0021] Figure 2 Schematic diagram of the traditional equivalent optical fingerprint recognition sensing circuit;

[0022] Figure 3 Schematic diagram of the traditional equivalent driving circuit;

[0023] Figure 4 Schematic diagram of the laminated structure of a liquid crystal screen of the traditional optical under-screen fingerprint recognition technology;

[0024] Figure 5 Schematic diagram of the under-screen fingerprint recognition circuit of the present invention;

[0025] Figure 6 Schematic diagram of the under-screen fingerprint recognition laminated structure of the present invention;

[0026] Figure 7 Perspective schematic diagram of the layout of the under-screen fingerprint recognition laminated structure of the present invention;

[0027] Figure 8 Schematic diagram of defining the picture output area and the fingerprint recognition area of a display panel;

[0028] Figure 9 Schematic diagram of the time-sharing operation of the picture output area and the fingerprint recognition area of a traditional display panel;

[0029] Figure 10 Schematic diagram of the time-sharing operation of the picture output area and the fingerprint recognition area of the display panel of the present invention.

[0030] Reference numerals: 10 pixels; 11 recognition sensing circuit; 12 equivalent driving circuit; 13 liquid crystal screen laminate structure; 130 display area; 131 touch area; 132 fingerprint recognition area; 1320 optical fingerprint recognizer; 134 transparent conductive layer; 2 under-screen fingerprint recognition circuit; 20 first transistor; 21 second transistor; 22 third transistor; 23 first capacitor; 24 second capacitor; 25 optical fingerprint sensor; 250 reset fingerprint information terminal; 251 fingerprint recognition selection terminal; 252 recognition output terminal; 26 display data receiving terminal; 27 data output terminal; 28 common ground terminal; 29 operating voltage terminal; 3 under-screen fingerprint recognition laminate structure; 30 substrate; 31 first unit; 310 buffer layer; 311 gate insulating layer; 312 interlayer dielectric layer; 313 planarization layer; 32 second unit; 321 first insulating layer; 322 second insulating layer; 323 third insulating layer; 33 shielding metal; 341 drain semiconductor component; 342 source semiconductor component; 343 polysilicon component; 344 gate semiconductor component; 35 first metal region; 36 second metal region; 37 third metal region; 38 common electrode; 390 first electrode; 391 second electrode; 4 pixel area; 40 display sub-area; 41 recognition sub-area; 42 touch sub-area; 6 display panel; 60 picture output area; 62 fingerprint recognition area; S101 display and touch period; S102 display and recognition period; S1011 to S1014 display screen and simultaneous touch sensing; S1021 display screen; S1022 start fingerprint recognition; S1023 display and fingerprint recognition exposure; S1024 draw fingerprint; S201 display and touch period; S202 recognition display period; S2011 to S2014 display screen and simultaneous touch sensing; S2021 reset stage; S2022 exposure stage; S2023 draw stage; S1 to S2, L1 to L4 markings. Detailed implementation manners

[0031] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

[0032] The present invention is an under-screen fingerprint recognition circuit. Please refer to Figure 5As shown, the under-screen fingerprint recognition circuit 2 includes a first transistor 20, a second transistor 21, a third transistor 22, a first capacitor 23, a second capacitor 24, and an optical fingerprint sensor 25. The drain of the first transistor 20 is connected to the display data receiving terminal 26. The gate of the first transistor 20 is connected to the data output terminal 27 and the reset fingerprint information terminal 250, for receiving a display driving signal from the data output terminal 27 or a reset fingerprint recognition signal from the reset fingerprint information terminal 250. The source of the first transistor 20 is connected to the optical fingerprint sensor 25, and then connected from the optical fingerprint sensor 25 to the common ground terminal 28. And the optical fingerprint sensor 25 is connected in parallel with the first capacitor 23, and a second capacitor 24 is further connected in parallel between the optical fingerprint sensor 25 and the first capacitor 23. The gate of the second transistor 21 is connected between the source of the first transistor 20 and the optical fingerprint sensor 25. The drain of the second transistor 21 is connected to the operating voltage terminal 29. The source of the second transistor 21 is connected to the drain of the third transistor 22. The gate of the third transistor 22 is connected to the fingerprint recognition selection terminal 251 for receiving a fingerprint recognition signal. The source of the third transistor 22 is connected to the recognition output terminal 252.

[0033] In this way, the traditional equivalent driving circuit and the equivalent optical fingerprint recognition sensing circuit can be integrated, so that the under-screen fingerprint recognition stacked structure designed according to this can reduce the equivalent electronic components in the design and reduce a lot of wiring space (for example: the space for setting conductive vias), and can increase the aperture ratio. The aperture ratio refers to the ratio between the light passing area that does not include the wiring area and the transistor area of the pixel and the entire pixel area.

[0034] In the present invention, when the first transistor 20 receives a reset fingerprint recognition signal from the reset fingerprint information terminal 250, it is in the recognition mode, and when the first transistor 20 does not receive a reset fingerprint recognition signal, it is in the display mode.

[0035] Furthermore, in the recognition mode, the under-screen fingerprint recognition circuit 2 will sequentially perform a reset stage, an exposure stage, and a drawing stage. During the reset stage, the first transistor 20 receives a reset fingerprint recognition signal from the reset fingerprint information terminal 250, turns on the first transistor 20, the second transistor 21, and the third transistor 22, and releases the parasitic capacitance in the lines of the second transistor 21 and the third transistor 22.

[0036] During the exposure stage, the first transistor 20 and the second transistor 21 are turned on and the third transistor is turned off, and the display driving signal will be stored in the first capacitor 23 first, and the optical fingerprint sensor 25 is activated.

[0037] In the drawing stage, the first transistor 20 is turned off, and the gate of the third transistor 22 receives an identification value signal (commonly referred to as Select, abbreviated as SEL) and is turned on. The second capacitor 24 is controlled to open its amplitude according to the fingerprint pattern sensed by the optical fingerprint sensor 25, so that the working voltage terminal 29 provides different magnitudes of working voltages, which are transmitted through the source, drain of the second transistor 21, the source, drain of the third transistor 22 to the identification output terminal 252 and output from the identification output terminal 252. At the same time, the display drive signal in the first capacitor 23 is transmitted to the display data receiving terminal 26. Herein, the so-called fingerprint pattern refers to the shape of the ridges and valleys of the fingerprint sensed by the optical fingerprint sensor 25, so as to control the magnitude of the working voltage passing through the second transistor 21, and achieve the purpose of drawing the fingerprint within this pixel.

[0038] In the display mode of the under-screen fingerprint identification circuit 2, the first transistor 20 and the second transistor 21 are turned on, while the third transistor 22 is turned off. The gate of the first transistor 20 receives the display drive signal from the data output terminal 27 and conveys the display drive signal to the display data receiving terminal 26. Although the second transistor 21 is in the on state, the third transistor 22 is turned off, and the working voltage cannot be output.

[0039] In the present invention, the first capacitor 23 is an energy storage capacitor, and the second capacitor 24 stabilizes the operation of the optical fingerprint sensor 25.

[0040] For an under-screen fingerprint identification stacked structure of the present invention, please refer to Figure 6 As shown, the under-screen fingerprint identification stacked structure 3 includes a substrate 30, a first unit 31 and a second unit 32. The substrate 30, the first unit 31 and the second unit 32 are stacked in sequence from bottom to top. A plurality of pixel regions 4 are jointly defined among the substrate 30, the first unit 31 and the second unit 32. At least a display sub-region 40 and an identification sub-region 41 are defined in a part of the pixel regions 4. The display component is arranged at the position of the first unit 31 opposite to the display sub-region 40, and the optical fingerprint sensor 25 is arranged at the position of the second unit 32 opposite to the display sub-region 40. An equivalent under-screen fingerprint identification circuit 2 is formed between the first unit 31 and the second unit 32, and the display component and the optical fingerprint sensor 25 are connected to the equivalent under-screen fingerprint identification circuit within the second unit 32.

[0041] In the present invention, the first unit 31 includes a buffer layer 310 (buffer Layer), a gate insulating layer 311, an interlayer dielectric layer 312 (inter layer dielectric, abbreviated as: ILD), and a planarization layer 313, which are stacked in sequence from bottom to top. A shielding metal 33 is provided at the projection position of the substrate 30 within the display sub-region 40. The buffer layer 310 is provided on the substrate 30 and covers the shielding metal 33. The shielding metal 33 shields the gate of the first transistor 20 to prevent the first transistor 20 from malfunctioning due to the influence of the backlight source below the substrate 30. Above the buffer layer 310, there are provided a drain semiconductor component 341 and a source semiconductor component 342 for the first transistor 20, the second transistor 21, and the third transistor 22, and a polysilicon component 343 for separating the drain semiconductor component 341 and the source semiconductor component 342. The gate insulating layer 311 is provided on the buffer layer 310 and covers the drain semiconductor component 341, the source semiconductor component 342, and the polysilicon component 343. A gate semiconductor component 344 and a first metal region 35 are provided above the gate insulating layer 311. The gate semiconductor component 344 and the first metal region 35 are not connected to each other in the gate insulating layer 311. The interlayer dielectric layer 312 (inter layer dielectric, abbreviated as: ILD) covers the gate semiconductor component 344 and the first metal region 35. A plurality of second metal regions 36 are provided on the interlayer dielectric layer 312. Each second metal region 36 is connected or not connected according to the design requirements in the planarization layer 313. The planarization layer 313 covers each second metal region 36. Since Figure 6 One of the under-screen fingerprint recognition stacked structures 3 mainly presents the stacked state of each layer and the positions of the components provided on each stack in a stacked structure schematic diagram, rather than completely presenting the fully equivalent stacked structure of the under-screen fingerprint recognition circuit (such as Figure 5 ), which is hereby stated first.

[0042] In the present invention, the second unit 32 includes a first insulating layer 321, a second insulating layer 322, and a third insulating layer 323 that are stacked in sequence from bottom to top. A plurality of third metal regions 37 are provided on the surface of the first insulating layer 321, and the third metal regions 37 are either connected or not connected to each other on the first insulating layer 321 according to design requirements. A common electrode 38 is provided on the surface of the second insulating layer 322 at positions corresponding to the display sub-region 40 and the identification sub-region 41. A plurality of first electrodes 390 are provided on the surface of the third insulating layer 323 at positions corresponding to the projection of the display sub-region 40. One of the first electrodes 390 extends outside the projection position of the display sub-region 40 and is sequentially connected to the third metal region 37, the second metal region 36, and the drain semiconductor component 341 through a metal via 5 provided in the underlying stacked structure. A second electrode 391 is provided on the surface of the third insulating layer 323 at positions corresponding to the projection of the identification sub-region 41. A display component is provided between the first electrode 390 and the common electrode 38 within the second insulating layer 322, and the display component (not shown in the figure) is excited by the first electrode 390 and the common electrode 38 according to a display driving signal. An optical fingerprint sensor 25 is provided between the second electrode 391 and the common electrode 38 within the second insulating layer 322. The second electrode 391 is connected to the third metal region 37, the second metal region 36, and the first metal region 35 through a metal via 5 provided therebelow.

[0043] In the present invention, the first electrode 390, the second electrode 391, and the common electrode 38 can be transparent electrodes, for example: Indium Tin Oxide (ITO), and Figure 6 it can be seen that the display sub-region 40 and the identification sub-region 41 use the common electrode 38, and the optical fingerprint sensor 25 is provided in the second unit. Therefore, the manufacturing process of this structure is relatively simple, and the optical fingerprint sensor 25 is closer to the surface.

[0044] Furthermore, one of the third metal regions 37 shields the optical fingerprint sensor 25 at the projection position corresponding to the identification sub-region 41 on the surface of the third insulating layer 323 to prevent the light source of the backlight module below the substrate 30 from interfering with the optical fingerprint sensor 25 and causing malfunction of the optical fingerprint sensor 25. Moreover, each pixel region 4 includes a touch sub-region 42, and a touch circuit is provided in the touch sub-region 42 of the second unit 32. That is, the present invention can not only perform fingerprint identification under the screen but also further perform touch operations.

[0045] Please refer to Figure 7 as shown Figure 7 is a perspective schematic layout diagram of the fingerprint identification layer structure under the screen of the present invention. It only shows the positions of some components and the signal input positions, and does not distinguish between solid and dashed lines according to the order of each layer. Moreover, Figure 7 it is mainly for the purpose of illustration and showing the positions for increasing the aperture ratio. It is stated first for clarification. In Figure 7The areas marked with S1 and S2 are the positions where the aperture ratio of the present invention is increased. In the traditional under-screen fingerprint recognition stacked structure, metal vias are provided in the areas corresponding to S1 and S2. Since the present invention does not require metal vias in the areas of S1 and S2, the aperture ratio is increased. In addition, the installation positions of the first capacitor 23 and the optical fingerprint sensor 25 are also marked on this figure respectively. The position marked L1 is the position connecting the fingerprint recognition selection terminal 251, the position marked L2 is the position connecting the scanning line and the reset fingerprint information terminal, the position marked L3 is the position connecting the display data line, the working voltage terminal 29, the driving line (trace line) of the touch sub-region, the shared electrode 38 and the common ground terminal 28, and the position marked L4 is the position connecting the data output terminal 27 and the recognition output terminal 252.

[0046] Please refer to Figure 8 As shown, the display panel 6 of the present invention includes a picture output area 60 and a fingerprint recognition area 62. Each pixel in the fingerprint recognition area 62 is respectively the aforementioned under-screen fingerprint recognition stacked structure 3, including a display sub-region 40, a recognition sub-region 41 and a touch sub-region 42. The difference between the picture output area 60 and the fingerprint recognition area 62 is that each pixel in the picture output area 60 respectively includes a display sub-region 40 and a touch sub-region 42, or all of the display panel 6 of the present invention is the fingerprint recognition area 62. Each pixel in the fingerprint recognition area 62 is respectively the aforementioned under-screen fingerprint recognition stacked structure 3, including a display sub-region 40, a recognition sub-region 41 and a touch sub-region 42.

[0047] Please refer to Figure 4 、 Figure 9 As shown, the display area 130, the touch area 131 and the fingerprint recognition area 132 of the traditional display panel also include a display sub-region 40, a touch sub-region 42 and a recognition sub-region 41 like the display panel 6 of the present invention. However, the structures of the traditional display panel and the display panel of the present invention are different. Therefore, the steps of fingerprint capture for traditional under-screen fingerprint recognition are as follows:

[0048] (S101) During display and touch, further, when multiple display screen simultaneous touch detections (S1010 - S1014) are performed during display and touch, at this time, the display area 130 and the touch area 131 are actuated. Here, taking four display screen simultaneous touch detections as an example;

[0049] (S102) Enter the display and recognition period. During the display and recognition period, the display area 130 and the fingerprint recognition area 132 are actuated. Further, it includes the following stages:

[0050] (S1021) Display the picture. At this time, the display area 130 outputs a frame of picture;

[0051] (S1022) Start fingerprint recognition. The display area 130 outputs a frame of image and activates the optical fingerprint recognizer 1320 in the fingerprint recognition area 132;

[0052] (S1023) Display and fingerprint recognition exposure. Further, the display area 130 outputs a frame of image and the fingerprint recognition area 132 performs fingerprint recognition exposure;

[0053] (S1024) Depict the fingerprint. The fingerprint recognition area 132 depicts the fingerprint;

[0054] Among them, the display area 130 operates during the display screen and the display and fingerprint recognition exposure phases, while the fingerprint recognition area 132 operates during the display screen, start fingerprint recognition, display and fingerprint recognition exposure and other phases, and the display and touch period and the display and recognition period are cycled.

[0055] However, the traditional fingerprint acquisition method for under-screen fingerprint recognition is not applicable to the display panel 6 of the present invention. Please refer to Figure 10 As shown, a fingerprint acquisition method for under-screen fingerprint recognition of the present invention is applied to the display panel 6 of the present invention. The fingerprint recognition area 62 of this display panel 6 includes a display sub-area 40, a recognition sub-area 41 and a touch sub-area 42, and includes the following steps:

[0056] (S201) During the display and touch period, the display sub-area 40 and the touch sub-area 42 output a plurality of display screens and perform touch sensing simultaneously according to the display driving signal (S2011~2014). In the present invention, four display screens are output and touch sensing is performed, but in actual implementation, it is not limited to this;

[0057] (S202) The recognition display period includes the following phases:

[0058] (S2021) In the reset phase, the display sub-area 40 outputs a display screen according to the display driving signal, and at the same time resets the recognition sub-area 42;

[0059] (S2022) Exposure phase. The display sub-area 40 maintains the display screen in the reset phase, and the recognition sub-area uses the light source of the display screen of the display sub-area as the exposure light source for fingerprint recognition;

[0060] (S2023) Output in the depiction phase. The display sub-area 40 maintains the display screen in the reset phase, and the recognition sub-area 41 starts to depict the fingerprint pattern;

[0061] Moreover, the display and touch period and the display and recognition period are cycled, and the reset phase, the exposure phase and the depiction phase are carried out within the time of outputting one frame of display screen respectively.

[0062] Furthermore, the aforementioned reset phase, exposure phase, and drawing phase are respectively the time for outputting one frame of image. However, in actual implementation, this is not the limit. In summary, from the foregoing content and Figure 9 , Figure 10 it can be seen that in the fingerprint acquisition method of the in-screen fingerprint identification of the present invention, it is completely different from the traditional fingerprint acquisition method of in-screen fingerprint identification.

[0063] As described above, the in-screen fingerprint identification circuit 2 integrates the traditional equivalent drive circuit and the equivalent optical fingerprint identification sensing circuit, reducing electronic components. As a result, in the in-screen fingerprint identification laminated structure made according to the equivalent circuit, due to the reduction of electronic components, the aperture ratio of the in-screen fingerprint identification laminated structure increases, achieving the purpose of improving the overall luminous efficiency. In addition, it also simplifies the production of the in-screen fingerprint identification laminated structure, reduces the manufacturing time, and achieves the purpose of reducing the production cost. Furthermore, the fingerprint acquisition method of in-screen fingerprint identification can maintain the output of the image, and can also perform fingerprint identification simultaneously, truly achieving the purpose of being able to perform fingerprint identification, and can even be used as a touch panel.

[0064] The above detailed description is a specific description of the feasible embodiments of the present invention. However, the foregoing embodiments are not intended to limit the patent scope of the present invention. Any equivalent implementation or modification made without departing from the technical spirit of the present invention shall be included in the patent scope of this case.

Claims

1. An under-screen fingerprint recognition circuit, characterized in that: Comprising: A first transistor, the drain of the first transistor being connected to a display data receiving terminal, the gate of the first transistor being connected to a data output terminal and a reset fingerprint information terminal, and receiving a display driving signal from the data output terminal or receiving a reset fingerprint identification signal from the reset fingerprint information terminal; An optical fingerprint sensor, the optical fingerprint sensor being connected between the source of the first transistor and a common ground terminal; A first capacitor, the first capacitor being connected in parallel with the optical fingerprint sensor; A second capacitor, the second capacitor being disposed between the first capacitor and the optical fingerprint sensor and being connected in parallel with the optical fingerprint sensor; A second transistor, the gate of the second transistor being connected between the source of the first transistor and the optical fingerprint sensor, the drain of the second transistor being connected to a working voltage terminal; A third transistor, the drain of the third transistor being connected to the source of the second transistor, the gate of the third transistor receiving a fingerprint identification signal, and the source of the third transistor being connected to an identification output terminal.

2. The under-screen fingerprint recognition circuit according to claim 1, wherein: When the first transistor receives the reset fingerprint identification signal from the reset fingerprint information terminal, it is in the identification mode, and when the first transistor does not receive the reset fingerprint identification signal, it is in the display mode. In the identification mode, the fingerprint identification signal is output from the reset fingerprint information terminal, and at the same time, the display driving signal is maintained at the source of the third transistor and output to the display data receiving terminal. In the display mode, only the display driving signal is output from the source of the first transistor to the display data receiving terminal.

3. The under-screen fingerprint recognition circuit according to claim 2, wherein: In the identification mode, a reset phase, an exposure phase, and a rendering phase are sequentially performed; During the reset phase: The first transistor receives the reset fingerprint identification signal from the reset fingerprint information terminal, turns on the first transistor, the second transistor, and the third transistor, so that the parasitic capacitance in the circuits of the second transistor and the third transistor is released; During the exposure phase: The first transistor and the second transistor are turned on and the third transistor is turned off, and the display driving signal is first stored in the first capacitor, and the optical fingerprint sensor is activated; Rendering phase: The first transistor is turned off, and the gate of the third transistor receives the identification value signal and is turned on. The second capacitor is controlled to open according to the fingerprint pattern sensed by the optical fingerprint sensor, so that the working voltage terminal provides different working voltages, and is transmitted to the identification output terminal through the source, drain of the second transistor, the source, and drain of the third transistor, and is output from the identification output terminal. At the same time, the display driving signal in the first capacitor is transmitted to the display data receiving terminal.

4. The under-screen fingerprint recognition circuit according to claim 2, wherein: In the display mode, the first transistor and the second transistor are turned on, and the third transistor is turned off. The gate of the first transistor receives the display driving signal from the data output terminal and transmits the display driving signal to the display data receiving terminal. Although the second transistor is in the on state, the third transistor is turned off and the working voltage cannot be output.

5. The under-screen fingerprint recognition circuit according to claim 1, characterized in that: The first capacitor is an energy storage capacitor.

6. An under-screen fingerprint recognition laminated structure, characterized in that: Comprising: A substrate; The first unit is disposed on the substrate; and the second unit is disposed on the first unit; wherein, a plurality of pixel regions are jointly defined among the substrate, the first unit and the second unit, at least a display sub-region and an identification sub-region are defined in each pixel region, and a fingerprint identification circuit under the screen as described in any one of claims 1 to 5 is formed; The display component is disposed at a position of the first unit corresponding to the display sub-region; and the optical fingerprint sensor is disposed at a position of the second unit corresponding to the identification sub-region.

7. The under-screen fingerprint recognition stacked structure according to claim 6, wherein: A shielding metal is disposed within the projection position of the substrate in the display sub-region, and the first unit includes: a buffer layer disposed on the substrate and covering the shielding metal, a drain semiconductor component and a source semiconductor component serving as the first transistor, the second transistor and the third transistor are disposed above the buffer layer, and a polysilicon component for separating each drain semiconductor component and each source semiconductor component; a gate insulating layer disposed on the buffer layer and covering each drain semiconductor component, each source semiconductor component and each polysilicon component, a gate semiconductor component of the first transistor, the second transistor and the third transistor and at least one first metal region are disposed above the gate insulating layer, and the shielding metal shields the gate semiconductor component, and each first metal region is not connected or is connected according to requirements on the gate insulating layer; an interlayer dielectric layer disposed on the gate insulating layer and covering the gate semiconductor component and the first metal region, and a plurality of second metal regions are disposed on the interlayer dielectric layer, and each second metal region is not connected or is connected according to requirements on the interlayer dielectric layer; and a planarization layer disposed on the interlayer dielectric layer and covering each second metal region.

8. The under-screen fingerprint recognition stacked structure according to claim 7, wherein: The second unit includes: a first insulating layer disposed on the planarization layer, and a plurality of third metal regions are disposed on the surface of the first insulating layer, and each third metal region is not connected or is connected according to design requirements on the first insulating layer; a second insulating layer disposed on the first insulating layer, and a common electrode is disposed on the surface of the second insulating layer at positions corresponding to the display sub-region and the identification sub-region; and a third insulating layer disposed on the second insulating layer, a first electrode is disposed on the surface of the third insulating layer at the projection position corresponding to the display sub-region, and a second electrode is disposed on the surface of the third insulating layer at the projection position corresponding to the identification sub-region; wherein a display component is disposed between the first electrode and the common electrode within the second insulating layer, and the display component is excited by the first electrode and the common electrode according to a display driving signal, an optical fingerprint sensor is disposed between the second electrode and the common electrode within the second insulating layer, one of the first electrodes extends outside the projection position of the display sub-region, and is sequentially connected to the third metal region, the second metal region and the drain semiconductor component through a metal through hole provided in the lower stacked structure, and further, the second electrode is sequentially connected to the third metal region, the second metal region and the first metal region below through a metal through hole provided below it.

9. The under-screen fingerprint recognition laminated structure according to claim 8, wherein: One of the third metal regions shields the optical fingerprint sensor at the projection position corresponding to the identification sub-region on the surface of the third insulating layer.

10. The under-screen fingerprint recognition stacked structure according to claim 8, wherein: Each pixel region includes a touch control sub-region, and a touch control circuit is disposed in the touch control sub-region of the second unit.

11. A display panel, comprising: a picture output area; and A fingerprint recognition area, where the fingerprint recognition area is the under-screen fingerprint recognition stacked structure described in claim 6; Among them, the difference between the picture output area and the fingerprint recognition area is that the picture output area only has a display sub-area, and the fingerprint recognition area is located within the picture output area, or the picture output area is a part of the display panel, while the fingerprint recognition area is located in another part of the display panel respectively.

12. A fingerprint acquisition method for fingerprint recognition under a screen, characterized in that: Applied to a display panel, the display panel defines a fingerprint recognition area, where the fingerprint recognition area is the under-screen fingerprint recognition stacked structure described in claim 10, and the fingerprint recognition area repeatedly performs the following steps during display and recognition: During the display period, the display sub-area and the recognition sub-area output a plurality of display pictures according to the display driving signal and perform touch sensing simultaneously; During the recognition and display period, it is output in a reset stage, an exposure stage, and a drawing stage; In the reset stage, the display sub-area outputs a display picture according to the display driving signal, and at the same time resets the recognition sub-area; In the exposure stage, the display sub-area maintains the display picture in the reset stage, and the recognition sub-area uses the light source of the display picture in the display sub-area as the exposure light source for fingerprint recognition; In the drawing stage, the display sub-area maintains the display picture in the reset stage, and the recognition sub-area starts to draw the fingerprint pattern.

13. The fingerprint acquisition method for under-screen fingerprint recognition according to claim 12, wherein: The reset stage, the exposure stage, and the drawing stage are carried out within the time of outputting one frame of display picture respectively.

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