Optical fingerprint sensing module, display panel and electronic device

Abstract

An optical fingerprint sensing module (300), a display panel (210) and an electronic device (200). The optical fingerprint sensing module (300) comprises: a pixel circuit array comprising a plurality of pixel circuits. The pixel circuit comprises: a light sensing unit (131) and a switching unit (132) connected with the light sensing unit (131), the light sensing unit (131) is used for converting a light signal into an electric signal, the light sensing unit (131) comprises a light receiving surface (302) for receiving light, the switching unit (132) is arranged on a side of the light sensing unit (131) away from the light receiving surface (302), and the light sensing unit (131) outputs the electric signal through the switching unit (132). By arranging the switching unit (132) on the side of the light sensing unit (131) away from the light receiving surface (302), the switching unit (132) provides a space for the light sensing unit (131), so that the size of the light sensing unit (131) can be increased under the premise of pixel resolution, the area of the light receiving surface (302) of the light sensing unit (131) is increased, and then the optical fingerprint sensing module (300) can accurately detect a fingerprint.

Description

Technical Field

[0001] This disclosure relates to the field of electronic device technology, and in particular to an optical fingerprint sensing module, a display panel, and an electronic device. Background Technology

[0002] With the rapid development of display technology, full-screen displays are becoming increasingly popular among users. To meet user demands, major manufacturers have proposed various solutions to increase screen-to-body ratio. For example, the optical fingerprint sensor module can be placed under the screen to achieve in-display fingerprint technology. The optical fingerprint sensor module includes multiple pixel circuits, each comprising photosensitive units and switching units arranged on the same layer. Increasing the area of ​​the photosensitive units allows each pixel circuit to receive more light, but this reduces the resolution of the pixel circuit. Therefore, designing an optical fingerprint sensor module that balances good resolution with the ability of the photosensitive units to receive a large amount of light is particularly important. Summary of the Invention

[0003] This disclosure provides an improved optical fingerprint sensing module, display panel, and electronic device.

[0004] One aspect of this disclosure provides an optical fingerprint sensing module, the optical fingerprint sensing module comprising: a pixel circuit array, the pixel circuit array including a plurality of pixel circuits; the pixel circuit including: a photosensitive unit and a switching unit connected to the photosensitive unit, the photosensitive unit being used to convert optical signals into electrical signals, the photosensitive unit including a light-receiving surface for receiving light, the switching unit being disposed on the side of the photosensitive unit opposite to the light-receiving surface, the photosensitive unit outputting the electrical signals through the switching unit.

[0005] Optionally, the optical fingerprint sensing module further includes wiring, at least a portion of which is connected to the pixel circuit, and the wiring is located on the side of the photosensitive unit away from the light receiving surface.

[0006] Optionally, the trace includes a scan line connected to the switching unit, and a first coupling capacitor for charge transfer is formed between the scan line and the photosensitive unit; the trace also includes a compensation line, and a compensation coupling capacitor for charge transfer is formed between the compensation line and the photosensitive unit; the optical fingerprint sensing module further includes a driving module connected to the compensation line and the scan line, the driving module being configured to: during the exposure of the photosensitive unit, before the switching unit is turned on, output a driving signal to the compensation line, so that the charge transfer direction between the compensation line and the photosensitive unit is opposite to the charge transfer direction between the scan line and the photosensitive unit.

[0007] Optionally, the pixel circuit is a passive pixel circuit, and the driving module is further configured to: during the exposure of the photosensitive unit, after the switching unit is turned off, output a driving signal to the compensation line so that the charge transfer direction between the compensation line and the photosensitive unit is opposite to the charge transfer direction between the scan line and the photosensitive unit.

[0008] Optionally, the driving module is configured to: send a scan signal to the scan line to control the switching unit to turn on; and make the rising edge of the driving signal after the falling edge of the scan signal, and make the falling edge of the driving signal before the rising edge of the scan signal.

[0009] Optionally, the size of the first coupling capacitor is equal to the size of the compensation coupling capacitor.

[0010] Optionally, the pixel circuit is an active pixel circuit, and the active pixel circuit further includes a reset unit connected to the photosensitive unit and the switching unit for resetting the photosensitive unit. The reset unit is located on the side of the photosensitive unit away from the light receiving surface.

[0011] Optionally, the trace further includes a reset line connected to the reset unit, wherein the reset line and the photosensitive unit form a second coupling capacitor for transmitting charge; the reset line is connected to the driving module, and the driving module is further configured to: drive the reset unit to close after the switch unit is closed, and output the driving signal to the compensation line after the reset unit is closed, so that the charge transmission direction between the compensation line and the photosensitive unit is opposite to the charge transmission direction between the reset line and the photosensitive unit.

[0012] Optionally, the driving module is configured to: send a scanning signal to the scan line to control the switching unit to turn on; and send a reset signal to the reset line, the reset signal being used to drive the reset unit to reset the photosensitive unit; and to ensure that the rising edge of the driving signal is after the falling edge of the reset signal, and that the falling edge of the driving signal is before the rising edge of the scan signal.

[0013] Optionally, the size of the second coupling capacitor is equal to the size of the compensation coupling capacitor.

[0014] Optionally, at least a portion of the scan line is disposed on the same layer as at least a portion of the compensation line; and / or, at least a portion of the scan line is disposed on the same layer as the switching unit.

[0015] Optionally, the optical fingerprint sensing module further includes a microlens array disposed on the side of the photosensitive unit away from the switching unit.

[0016] Optionally, the optical fingerprint sensing module further includes a collimator disposed between the microlens array and the photosensitive unit, the collimator having a collimation hole that connects the microlens array and the photosensitive unit.

[0017] Another aspect of this disclosure provides a display panel comprising any of the aforementioned optical fingerprint sensing modules.

[0018] Another aspect of this disclosure provides an electronic device that includes the aforementioned display panel.

[0019] This disclosure arranges the switching unit on the side of the photosensitive unit away from the light-receiving surface, that is, the switching unit and the photosensitive unit are arranged on different layers. This allows the switching unit to provide space for the photosensitive unit, so as to increase the size of the photosensitive unit while ensuring pixel resolution, and increase the amount of light received by the photosensitive unit, thereby facilitating the accurate detection of fingerprints by the optical fingerprint sensing module. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 The image shown is a partial cross-sectional view of a display panel as illustrated in an exemplary embodiment.

[0022] Figure 2 As shown Figure 1 A partial cross-sectional view of the optical fingerprint sensor module.

[0023] Figure 3 As shown Figure 2 A partially enlarged schematic diagram of the optical fingerprint sensor module.

[0024] Figure 4 As shown Figure 1 A top view of the optical fingerprint sensor module.

[0025] Figure 5 The diagram shown is a structural schematic of an electronic device according to an exemplary embodiment of the present disclosure.

[0026] Figure 6 The image shown is a partial cross-sectional view of an optical fingerprint sensing module according to an exemplary embodiment of this disclosure.

[0027] Figure 7The diagram shown is a partial schematic of a pixel circuit array according to an exemplary embodiment of the present disclosure.

[0028] Figure 8 The diagram shown is a partial schematic of a pixel circuit array according to an exemplary embodiment of the present disclosure.

[0029] Figure 9 The image shown is a partial cross-sectional view of an optical fingerprint sensing module according to an exemplary embodiment of this disclosure.

[0030] Figure 10 The diagram shown is a schematic representation of the formation of a first coupling capacitor and a compensation coupling capacitor according to an exemplary embodiment of this disclosure.

[0031] Figure 11 The diagram shown is a timing diagram of the operation of the scan lines and compensation lines according to an exemplary embodiment of this disclosure.

[0032] Figure 12 The diagram shown is a circuit diagram of an active pixel circuit according to an exemplary embodiment of this disclosure.

[0033] Figure 13 The diagram shown is a partial schematic of a pixel circuit array according to an exemplary embodiment of the present disclosure.

[0034] Figure 14 The diagram shown is a schematic representation of the formation of a first coupling capacitor, a second coupling capacitor, and a compensation coupling capacitor according to an exemplary embodiment of this disclosure.

[0035] Figure 15 The diagram shown is a timing diagram illustrating the operation of the scan line, compensation line, and reset line according to an exemplary embodiment of this disclosure. Detailed Implementation

[0036] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this disclosure.

[0037] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses consistent with some aspects of this disclosure as detailed in the appended claims.

[0038] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items. Unless otherwise indicated, terms such as “front,” “rear,” “lower,” and / or “upper” are for illustrative purposes only and are not intended to limit a location or spatial orientation. Terms such as “connected” or “linked” are not limited to physical or mechanical connections and can include electrical connections, whether direct or indirect. Terms such as “a plurality” or “several” indicate two or more.

[0039] Figure 1 The image shown is a partial cross-sectional view of a display panel illustrating an exemplary embodiment. In some embodiments, reference is made to... Figure 1 The display panel includes a display layer 110, a cover layer 120 disposed above the display layer 110, and an optical fingerprint sensing module 130 disposed below the display layer 110. The display layer 110 is an OLED (Organic Light-Emitting Diode) display layer. When a finger 140 is pressed against the cover layer 120, the OLED display layer 110 emits light towards the finger 140. The light is reflected by the ridges and valleys of the fingerprint and then received by the optical fingerprint sensing module 130. The fingerprint is detected based on the light received by the optical fingerprint sensing module 130.

[0040] Figure 2 As shown Figure 1 A partial cross-sectional view of the optical fingerprint sensor module 130. Figure 3 As shown Figure 2 A partially enlarged schematic diagram of the optical fingerprint sensor module 130. Figure 4 As shown Figure 1 A top view of the optical fingerprint sensing module 130. The optical fingerprint sensing module 130 includes a pixel circuit array, which comprises multiple pixel circuits. (Reference) Figure 2 The pixel circuit includes a photosensitive unit 131 and a switching unit 132 connected to the photosensitive unit 131, with the photosensitive unit 131 and the switching unit 132 disposed on the same layer. The photosensitive unit 131 converts light into an electrical signal and outputs the electrical signal through the switching unit 132. The shape of the fingerprint can be determined based on this electrical signal.

[0041] Reference Figure 2 and Figure 3The optical fingerprint sensing module 130 also includes a collimator 133 disposed on the light receiving surface side of the photosensitive unit 131, and a microlens array 134 disposed on the light incident side of the collimator 133. The collimator 133 has a collimation hole 135, which is used to collimate the light passing through the microlens array 134 onto the photosensitive unit 131. For example, in... Figure 3 In the process, the collimator 133 allows solid light rays to pass through the collimation hole 135 and illuminate the photosensitive unit 131, while blocking dashed light rays from illuminating the photosensitive unit 131. This avoids the superposition of light reflected from the ridges and valleys of the fingerprint, which would cause light mixing problems and facilitates the accurate detection of fingerprints by the optical fingerprint sensing module 130.

[0042] Reference Figure 2 and Figure 4 If part of the collimating aperture 135 is not aligned with the photosensitive unit 131, but is aligned with the switching unit 132, then the switching unit 132 can receive the light collimated by the collimating aperture 135. The area in which the switching unit 132 receives light is called the switching unit area 136. See [link to relevant documentation]. Figure 4 This reduces the amount of light received by the photosensitive unit 131, which is detrimental to the accurate fingerprint detection of the optical fingerprint sensing module 130. Aligning all the collimating holes 135 with the photosensitive unit 131 would allow the photosensitive unit 131 to receive more light, thus improving fingerprint detection accuracy, but this increases production costs. Increasing the area of ​​the photosensitive unit 131 would reduce the number of photosensitive units 131 due to the limited area of ​​the pixel array, thus lowering the resolution of the optical fingerprint sensing module 130. Furthermore, due to process limitations, it is difficult to miniaturize the switching unit 132. Therefore, the aforementioned optical fingerprint sensing module 130 cannot simultaneously achieve both good resolution and the ability of the photosensitive unit 131 to receive a large amount of light.

[0043] To address the aforementioned problems, this disclosure provides an optical fingerprint sensing module, a display panel, and an electronic device, which are described below in conjunction with the accompanying drawings:

[0044] In this disclosure, electronic devices include, but are not limited to: mobile phones, tablets, iPads, digital broadcasting terminals, messaging devices, game consoles, medical devices, fitness equipment, personal digital assistants, and other smart devices.

[0045] Figure 5 The diagram shown is a structural schematic of an electronic device 200 according to an exemplary embodiment of the present disclosure. Figure 6 The image shown is a partial cross-sectional view of an optical fingerprint sensing module 300 according to an exemplary embodiment of this disclosure. (See reference...) Figure 5 The electronic device 200 includes a display panel 210, and the display panel 210 includes an optical fingerprint sensing module 300 (see reference). Figure 6The display area of ​​the display panel 210 forms a fingerprint detection area 220, and the optical fingerprint sensing module 300 is disposed in the fingerprint detection area 220.

[0046] In some embodiments, the display panel 210 further includes a display layer (not shown), which includes a display surface. An optical fingerprint sensing module 300 is disposed on the side of the display layer opposite to the display surface to achieve under-display fingerprint technology, thereby improving the screen-to-body ratio. In other embodiments, the optical fingerprint sensing module 300 is integrated with the display layer, which helps to reduce the thickness of the display panel 210 and to miniaturize the display panel 210 and the electronic device 200.

[0047] Figure 7 The diagram shown is a partial schematic of a pixel circuit array according to an exemplary embodiment of the present disclosure. Figure 8 The diagram shown is a partial schematic of a pixel circuit array according to an exemplary embodiment of this disclosure. (Referring to reference...) Figures 6 to 8 The optical fingerprint sensing module 300 includes a pixel circuit array 301. The pixel circuit array 301 includes multiple pixel circuits 310. Exemplarily, the multiple pixel circuits 310 are arranged in multiple rows and columns, or in multiple rows and columns. Each pixel circuit 310 includes a photosensitive unit 311 and a switching unit 312 connected to the photosensitive unit 311. The photosensitive unit 311 converts light signals into electrical signals and includes a light-receiving surface 302 for receiving light. The switching unit 312 is located on the side of the photosensitive unit 311 opposite to the light-receiving surface 302, and the photosensitive unit 311 outputs electrical signals through the switching unit 312. In other words, the photosensitive unit 311 and the switching unit 312 are located on different layers, such as... Figure 7 The diagram shows the arrangement of the photosensitive unit 311 on one layer. Figure 8 The diagram shows the layout of the switch unit 312 on another layer.

[0048] For example, the photosensitive unit 311 includes a photodiode, and the switching unit 312 includes a TFT (Thin Film Transistor). (Refer to...) Figure 6 The TFT can be directly formed on the glass substrate 320. For example, the photosensitive unit 311 and the switching unit 312 can be positioned relative to each other by means of an insulating resin substrate 330, so that the switching unit 312 is fixed on the side opposite to the light receiving surface 302 of the photosensitive unit 311.

[0049] Based on the above, by placing the switch unit 312 on the side of the photosensitive unit 311 away from the light receiving surface 302, that is, placing the switch unit 312 and the photosensitive unit 311 on different layers, the switch unit 312 provides space for the photosensitive unit 311. This allows for increasing the size of the photosensitive unit 311 and the area of ​​the light receiving surface 302 of the photosensitive unit 311 while ensuring the number of pixel circuits 310 and pixel resolution. This increases the amount of light received by the photosensitive unit 311 and facilitates accurate fingerprint detection by the optical fingerprint sensing module 300.

[0050] Please continue to refer to this. Figure 6 In some embodiments, the optical fingerprint sensing module 300 further includes a microlens array 340 disposed on the side of the photosensitive unit 311 opposite to the switching unit 312. The microlens array 340 is used to focus light so that light can effectively illuminate the photosensitive unit 311. Exemplarily, the microlens array 340 includes a plurality of microlenses arranged in an array. Exemplarily, one microlens corresponds to a plurality of photosensitive units 311. Exemplarily, multiple microlenses correspond to one photosensitive unit 311.

[0051] Please continue to refer to this. Figure 6 In some embodiments, the optical fingerprint sensing module 300 further includes a collimator 350 disposed between the microlens array 340 and the photosensitive unit 311. The collimator 350 has a collimation hole 351 that connects the microlens array 340 and the photosensitive unit 311. The collimation hole 351 achieves a light-receiving and collimating effect, avoiding the superposition of light reflected from the ridges and valleys of the fingerprint and thus preventing light mixing problems caused by the superposition of light, which is beneficial for the optical fingerprint sensing module 300 to accurately detect fingerprints.

[0052] Figure 9 The image shown is a partial cross-sectional view of an optical fingerprint sensing module 300 according to an exemplary embodiment of this disclosure. In some embodiments, reference is made to... Figure 6 , Figure 8 and Figure 9 The optical fingerprint sensing module 300 also includes a trace 360, at least a portion of which is connected to the pixel circuit 310. The trace 360 ​​is located on the side of the photosensitive unit 311 facing away from the light receiving surface 302. This avoids the trace 360 ​​occupying the gap between photosensitive units 311, allowing for a larger size of the photosensitive unit 311 while maintaining the resolution of the optical fingerprint sensing module 300. This increases the amount of light received by the photosensitive unit 311, thereby facilitating accurate fingerprint detection by the optical fingerprint sensing module 300.

[0053] Based on the above, although at least some of the traces 360 and the photosensitive unit 311 are located on different layers, the traces 360 are prone to forming coupling capacitors with the photosensitive unit 311. When components such as the switching unit 312 are turned on or off, the switching unit 312 and other components are prone to outputting charges to the photosensitive unit 311 through the coupling capacitors, or receiving charges output by the photosensitive unit 311 through the coupling capacitors, which will interfere with the electrical signals of the photosensitive unit 311.

[0054] Figure 10 The diagram shown is a schematic representation of the formation of a first coupling capacitor 371 and a compensation coupling capacitor 372 according to an exemplary embodiment of this disclosure. To address the above-mentioned problems, in some embodiments, reference is made to... Figures 8 to 10 The trace 360 ​​includes a gateline 361 connected to the switching unit 312, and a first coupling capacitor 371 for charge transfer is formed between the gateline 361 and the photosensitive unit 311. The trace 360 ​​also includes a compensation line 362, and a compensation coupling capacitor 372 for charge transfer is formed between the compensation line 362 and the photosensitive unit 311. The optical fingerprint sensing module 300 also includes a driving module 381 connected to the compensation line 362 and the gateline 361. The driving module 381 is used to: during the exposure of the photosensitive unit 311, before the switching unit 312 is turned on, output a driving signal to the compensation line 362, so that the charge transfer direction between the compensation line 362 and the photosensitive unit 311 is opposite to the charge transfer direction between the gateline 361 and the photosensitive unit 311, that is, output a compensation signal to the photosensitive unit 311 through the compensation coupling capacitor 372 before the switching unit 312 is turned on. In some embodiments, the pixel circuit 310 is a passive pixel circuit, and the driving module 381 is further configured to: during the exposure of the photosensitive unit 311, after the switching unit 312 is turned off, output a driving signal to the compensation line 362, so that the charge transfer direction between the compensation line 362 and the photosensitive unit 311 is opposite to the charge transfer direction between the scan line 361 and the photosensitive unit 311. It should be noted that the exposure period of the photosensitive unit 311 in the passive pixel circuit refers to the period from when the switching unit 312 is turned off to when the switching unit 312 is turned on again, and until the electrical signal of the photosensitive unit 311 is read (corresponding to...). Figure 11 (The time period t1-t5). After the switching unit 312 is turned off and before it is turned on, the driving module 381 outputs a driving signal to the compensation line 362, causing the charge transfer direction between the compensation line 362 and the photosensitive unit 311 to be opposite to the charge transfer direction between the scan line 361 and the photosensitive unit 311. This eliminates interference caused by the turning on and off of the switching unit 312, thereby ensuring the accuracy of reading the electrical signal from the photosensitive unit 311. To better understand how interference is eliminated by the compensation line 362, the following embodiments are provided:

[0055] Figure 11The diagram shows the operating timing of scan line 361 and compensation line 362 according to an exemplary embodiment of this disclosure. In some embodiments, the driving module 381 is configured to: send a scan signal to scan line 361 to control the switching unit 312 to turn on; and to position the rising edge t2 of the driving signal after the falling edge t1 of the scan signal, and to position the falling edge t3 of the driving signal before the rising edge t4 of the scan signal. In some embodiments, the switching unit 312 and compensation line 362 are driven to operate when both the scan signal and the driving signal are high-level pulse signals. In other words, referring to... Figure 11 At the rising edge of the scan signal, the switching unit 312 is turned on, and at the falling edge of the scan signal, the switching unit 312 is turned off. At the rising edge of the drive signal, the compensation line 362 starts working, and at the falling edge of the drive signal, the compensation line 362 stops working.

[0056] Specifically, refer to Figure 11During the period from time t0 to time t1, the scan signal drives the switch unit 312 to open, resetting the photosensitive unit 311. During the period from time t1 to time t4, the switch unit 312 is closed. During the period from time t2 to time t3, the drive module 381 sends a drive signal to the compensation line 362. At times t2 and t3, the compensation line 362 transfers charge between itself and the photosensitive unit 311 through the compensation coupling capacitor 372 according to the rising and falling edges of the drive signal. From time t4 to time t5, the switch unit 312 is open, and the photosensitive unit 311 continues to accumulate and stabilize the light signal. At time t5, the electrical signal converted from the light signal by the photosensitive unit 311 is read. Here, time t1 to time t5 is the exposure period of the photosensitive unit 311, and t5 is the eve of the rising edge of the scan line, that is, a moment before the switch unit closes. At the falling edge t1 of the scan signal, scan line 361 receives a portion of the charge output by photosensitive unit 311 through the first coupling capacitor 371. This affects the electrical signal of photosensitive unit 311. By making the rising edge t2 of the drive signal after the falling edge t1 of the scan signal, compensation line 362 outputs a portion of the charge to photosensitive unit 311 through compensation coupling capacitor 372 to compensate for the charge lost by photosensitive unit 311, thereby ensuring the stability of the electrical signal of photosensitive unit 311. At the rising edge t4 of the scan signal, scan line 361 outputs a portion of the charge to photosensitive unit 311 through the first coupling capacitor 371. By making the falling edge t3 of the drive signal before the rising edge t4 of the scan signal, compensation line 362 receives a portion of the charge output by photosensitive unit 311 through compensation coupling capacitor 372 to compensate for the portion of the charge input by scan line 361 to photosensitive unit 311 through the first coupling capacitor 371, thereby ensuring the stability of the electrical signal of photosensitive unit 311. At time t5, the electrical signal of the photosensitive unit 311 is read. The magnitude of the scan signal ΔVG can be equal to the magnitude of the drive signal ΔVD, which helps to make the amount of charge output or received by the compensation line 362 through the compensation coupling capacitor 372 equal to the amount of charge output or received by the scan line 361 through the first coupling capacitor 371, thereby effectively ensuring the stability of the electrical signal of the photosensitive unit 311.

[0057] In addition, the scanning signal and the drive signal can also be low-level pulse signals, and the working principle is similar to that described above, so they will not be described in detail here.

[0058] Furthermore, in some embodiments, the size of the first coupling capacitor 371 is equal to the size of the compensation coupling capacitor 372. For example, refer to... Figure 8The scan line 361 and the compensation line 362 have the same structure and arrangement, which facilitates making the first coupling capacitor 371 formed by the scan line 361 and the photosensitive unit 311 equal to the compensation coupling capacitor 372 formed by the compensation line 362 and the photosensitive unit 311. This ensures that the amount of charge output by the compensation line 362 to the photosensitive unit 311 through the compensation coupling capacitor 372 is equal to the amount of charge output by the photosensitive unit 311 to the scan line 361 through the first coupling capacitor 371, and that the amount of charge received by the photosensitive unit 311 from the scan line 361 through the first coupling capacitor 371 is equal to the amount of charge output by the photosensitive unit 311 to the compensation line 362 through the compensation coupling capacitor 372, thereby effectively stabilizing the electrical signal of the photosensitive unit 311.

[0059] In some embodiments, referring to 8, the optical fingerprint sensing module 300 further includes an amplification module 382 and an analog-to-digital converter module 383. The wiring 360 also includes a data line 363 connected to the output terminal of the switching unit 312 for outputting the electrical signal from the photosensitive unit 311. The amplification module 382 is connected to the data line 363, and the analog-to-digital converter module 383 is connected to the amplification module 382. The amplification module 382 amplifies the electrical signal output by the photosensitive unit 311, and the analog-to-digital converter module 383 converts the electrical signal into a digital signal to facilitate the formation of a digital image of the fingerprint.

[0060] In other embodiments, the pixel circuit 310 is an active pixel circuit, and the difference between an active pixel circuit and a passive pixel circuit is as follows:

[0061] Figure 12 The diagram shown is a circuit diagram of an active pixel circuit according to an exemplary embodiment of this disclosure. Figure 13 The diagram shown is a partial schematic of a pixel circuit array according to an exemplary embodiment of this disclosure. (Referring to reference...) Figure 12 and Figure 13 The active pixel circuit also includes a reset unit 313, connected to the photosensitive unit 311 and the switching unit 312, for resetting the photosensitive unit 311. The reset unit 313 is located on the side of the photosensitive unit 311 away from the light-receiving surface 302. The active pixel circuit also includes a source follower unit 314, one end of which is connected between the photosensitive unit 311 and the reset unit 313, and the other end is connected to the switching unit 312. The source follower unit 314 is located on the side of the photosensitive unit 311 away from the light-receiving surface 302. (Reference) Figure 13 The switching unit 312, the reset unit 313, and the source follower unit 314 are located on the same layer, and together with Figure 7The photosensitive units 311 are located on different layers. In this way, the reset unit 313 and the source follower unit 314 are avoided from occupying the gap between the photosensitive units 311, which allows the size of the photosensitive units 311 to be increased, thereby increasing the amount of light received by the photosensitive units 311, and thus facilitating the accurate detection of fingerprints by the optical fingerprint sensing module 300.

[0062] Figure 14 The diagram shown is a schematic representation of the formation of a first coupling capacitor 371, a second coupling capacitor 373, and a compensation coupling capacitor 372 according to an exemplary embodiment of this disclosure. (Referring to the reference...) Figure 13 and Figure 14 In some embodiments, trace 360 ​​further includes a reset line 364 connected to the reset unit 313, and a second coupling capacitor 373 for charge transfer is formed between the reset line 364 and the photosensitive unit 311. The reset line 364 is connected to the drive module 381, which is further configured to: drive the reset unit 313 to close after the switch unit 312 is closed, and output a drive signal to the compensation line 362, causing the charge transfer direction between the compensation line 362 and the photosensitive unit 311 to be opposite to the charge transfer direction between the reset line 364 and the photosensitive unit 311. After the drive module 381 drives the reset unit 313 to reset the photosensitive unit 311, the photosensitive unit 311 begins exposure until the electrical signal output by the photosensitive unit 311 is read. However, when the reset unit 313 is closed, the photosensitive unit 311 outputs charge to the reset line 364 through the second coupling capacitor 373, which affects the accuracy of reading the electrical signal of the photosensitive unit 311. After the reset unit 313 is turned off, the drive module 381 outputs a drive signal to the compensation line 362, causing the charge transfer direction between the compensation line 362 and the photosensitive unit 311 to be opposite to the charge transfer direction between the reset line 364 and the photosensitive unit 311. This eliminates interference signals caused when the reset unit 313 is turned off, thereby ensuring the accuracy of reading the electrical signals of the photosensitive unit 311. To better understand how interference is eliminated by the compensation line 362, the following embodiment is given:

[0063] Figure 15The diagram shows the operating timing of scan line 361, compensation line 362, and reset line 364 according to an exemplary embodiment of this disclosure. In some embodiments, the driving module 381 is configured to: send a scan signal to scan line 361 to control the switching unit 312 to turn on; and send a reset signal to reset line 364, the reset signal being used to drive reset unit 313 to reset photosensitive unit 311; and to ensure that the rising edge time t8 of the driving signal is after the falling edge time t7 of the reset signal, and that the falling edge time t9 of the driving signal is before the rising edge time t10 of the scan signal. In some embodiments, when the reset signal is a high-level pulse signal, the reset unit 313 is driven to operate. In other words, the reset unit 313 is turned on at the rising edge of the reset signal and turned off at the falling edge of the reset signal. When both the driving signal and the scan signal are high-level pulse signals, the compensation line 362 and the switching unit 312 are operated.

[0064] Specifically, refer to Figure 15 During the period from time t6 to time t7, the reset signal drives the reset unit 313 to reset the photosensitive unit 311. During the period from time t8 to time t9, the drive module 381 sends a drive signal to the compensation line 362. During the period from time t10 to time t11, the switch unit 312 turns on, and the photosensitive unit 311 continues to accumulate and stabilize the light signal. At time t11, the electrical signal converted from the light signal by the photosensitive unit 311 is read. t11 is the eve of the rising edge of the scan line, that is, a moment close to the time before the switch unit turns off. The period from time t7 to time t11 is the exposure period of the photosensitive unit 311. The turning off time t7 of the reset unit 313 is after the turning off time of the switch unit 312; in other words, the falling edge time t7 of the reset signal is after the falling edge time of the scan signal. After the switching unit 312 is turned off, the potential at point P of the photosensitive unit 311 is maintained at the potential VRST of the reset unit 313. Therefore, compensation for the falling edge of the scan signal is not required, reducing the number of compensation cycles for the driving module 381 driving the compensation line 362, and achieving a good compensation effect. The rising edge time t8 of the driving signal transmitted by the compensation line 362 is located after the falling edge time t7 of the reset signal. The compensation line 362 outputs charge to the photosensitive unit 311 through the compensation coupling capacitor 372 to compensate for the charge lost by the photosensitive unit 311 to the reset line 364 through the second coupling capacitor 373 due to the falling edge of the reset signal. Then, the falling edge time t9 of the drive signal sent by the drive module 381 to the compensation line 362 is before the rising edge time t10 of the scan signal. This causes the compensation line 362 to receive the amount of charge output by the photosensitive unit 311 through the compensation coupling capacitor 372, so as to compensate the amount of charge input by the scan line 361 to the photosensitive unit 311 through the first coupling capacitor 371, thereby ensuring the stability of the electrical signal of the photosensitive unit 311.

[0065] In addition, the scan signal, drive signal, and reset signal can also be low-level pulse signals, and their working principle is similar to that described above, so they will not be detailed here.

[0066] In some embodiments, the magnitude of the reset signal is equal to the magnitude of the drive signal, which helps to ensure that the amount of charge received or output by the compensation line 362 through the compensation coupling capacitor 372 is equal to the amount of charge output or received by the reset line 364 through the second coupling capacitor 373, thereby effectively ensuring the stability of the electrical signal of the photosensitive unit 311. In some embodiments, the magnitude of the second coupling capacitor 373 is equal to the magnitude of the compensation coupling capacitor 372. For example, refer to... Figure 13 The reset line 364 and the compensation line 362 have the same structure and layout, which facilitates making the second coupling capacitor 373 formed by the reset line 364 and the photosensitive unit 311 equal to the compensation coupling capacitor 372 formed by the compensation line 362 and the photosensitive unit 311. This ensures that the amount of charge output by the photosensitive unit 311 to the reset line 364 through the second coupling capacitor 373 is equal to the amount of charge output by the compensation line 362 to the photosensitive unit 311 through the compensation coupling capacitor 372, or that the amount of charge output by the reset line 364 to the photosensitive unit 311 through the second coupling capacitor 373 is equal to the amount of charge output by the photosensitive unit 311 to the compensation line 363 through the compensation coupling capacitor 372, thereby effectively stabilizing the electrical signal of the photosensitive unit 311.

[0067] In some embodiments, at least a portion of the scan line 361 and at least a portion of the compensation line 362 are disposed on the same layer; and / or, at least a portion of the scan line 361 and the switching unit 312 are disposed on the same layer. This facilitates the reduction in the thickness of the optical fingerprint sensing module 300.

[0068] The optical fingerprint sensing module 300, display panel 210, and electronic device 200 provided in this embodiment are based on the fact that the switching unit 312 and the wiring 360 are located on the side of the photosensitive unit 311 away from the light receiving surface 302. This provides space for the photosensitive unit 311, allowing for a larger size of the photosensitive unit 311 and an increased area of ​​the light receiving surface 302 of the photosensitive unit 311, while ensuring the number of pixel circuits 310 and pixel resolution. This increases the amount of light received by the photosensitive unit 311, which is beneficial for the optical fingerprint sensing module 300 to accurately detect fingerprints. Furthermore, it eliminates the need for precision equipment to align the photosensitive unit 311 with the collimation hole 351 of the collimator 350, reducing production costs and enhancing the competitiveness of the display panel 210 and electronic device 200. In addition, at least a portion of the wiring 360 is arranged on the same layer as the switching unit 312, which helps to reduce the thickness of the optical fingerprint sensing module 300, display panel 210, and electronic device 200.

[0069] The various embodiments disclosed above can complement each other without causing conflict.

[0070] The above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. An optical fingerprint sensing module, characterized in that, The optical fingerprint sensing module comprises: a pixel circuit array comprising a plurality of pixel circuits; the pixel circuit comprises a light sensing unit and a switch unit connected to the light sensing unit, the light sensing unit is used for converting a light signal into an electrical signal, the light sensing unit comprises a light receiving surface for receiving light, the switch unit is arranged on a side of the light sensing unit away from the light receiving surface, and the light sensing unit outputs the electrical signal through the switch unit; the optical fingerprint sensing module further comprises a wiring, at least part of the wiring is connected to the pixel circuit, and the wiring is arranged on a side of the light sensing unit away from the light receiving surface; the wiring comprises a scan line connected to the switch unit, a first coupling capacitor for transmitting electric charges is formed between the scan line and the light sensing unit; the wiring further comprises a compensation line, and a compensation coupling capacitor for transmitting electric charges is formed between the compensation line and the light sensing unit.

2. The optical fingerprint sensing module according to claim 1, wherein, The optical fingerprint sensing module further comprises a driving module connected to the compensation line and the scan line, and the driving module is used for: during exposure of the light sensing unit, outputting a driving signal to the compensation line before the switch unit is turned on, so that the direction of charge transmission between the compensation line and the light sensing unit is opposite to the direction of charge transmission between the scan line and the light sensing unit.

3. The optical fingerprint sensing module according to claim 2, wherein, The pixel circuit is a passive pixel circuit, and the driving module is further used for: during exposure of the light sensing unit, outputting a driving signal to the compensation line after the switch unit is turned off, so that the direction of charge transmission between the compensation line and the light sensing unit is opposite to the direction of charge transmission between the scan line and the light sensing unit.

4. The optical fingerprint sensing module according to claim 3, wherein, The driving module is used for: sending a scan signal for controlling the switch unit to be turned on to the scan line; and making the rising edge time of the driving signal be after the falling edge time of the scan signal, and making the falling edge time of the driving signal be before the rising edge time of the scan signal.

5. The optical fingerprint sensing module according to claim 2, wherein, The size of the first coupling capacitor is equal to the size of the compensation coupling capacitor.

6. The optical fingerprint sensing module according to claim 2, wherein, The pixel circuit is an active pixel circuit, and the active pixel circuit further comprises a reset unit connected to the light sensing unit and the switch unit, and used for resetting the light sensing unit, the reset unit is arranged on a side of the light sensing unit away from the light receiving surface.

7. The optical fingerprint sensing module according to claim 6, wherein, The wiring further comprises a reset line connected to the reset unit, and a second coupling capacitor for transmitting electric charges is formed between the reset line and the light sensing unit; the reset line is connected to the driving module, and the driving module is further used for: driving the reset unit to be turned off after the switch unit is turned off, and outputting the driving signal to the compensation line, so that the direction of charge transmission between the compensation line and the light sensing unit is opposite to the direction of charge transmission between the reset line and the light sensing unit.

8. The optical fingerprint sensing module according to claim 7, wherein, The driving module is used for: sending a scan signal for controlling the switch unit to be turned on to the scan line; and sending a reset signal to the reset line, the reset signal is used for driving the reset unit to reset the light sensing unit; The rising edge of the driving signal is located after the falling edge of the reset signal, and the falling edge of the driving signal is located before the rising edge of the scanning signal.

9. The optical fingerprint sensing module according to claim 7, wherein, The size of the second coupling capacitor is equal to the size of the compensation coupling capacitor.

10. The optical fingerprint sensing module according to claim 2, wherein, At least part of the scanning line and at least part of the compensation line are arranged on the same layer; and / or, At least part of the scanning line and the switch unit are arranged on the same layer.

11. The optical fingerprint sensing module according to claim 1, wherein, The optical fingerprint sensing module further comprises a microlens array arranged on the side of the photosensitive unit away from the switch unit.

12. The optical fingerprint sensing module according to claim 11, wherein, The optical fingerprint sensing module further comprises a collimating member arranged between the microlens array and the photosensitive unit, and the collimating member is provided with a collimating hole for guiding the microlens array and the photosensitive unit.

13. A display panel, characterized by The display panel comprises the optical fingerprint sensing module of any one of claims 1-12.

14. An electronic device, comprising: The electronic device comprises the display panel of claim 13.

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