Pixel driving circuit and display panel

Abstract

The application discloses a pixel driving circuit and a display panel. The pixel driving circuit comprises a display driving circuit and a sensing driving circuit in each pixel area. The sensing driving circuit comprises a sensing unit, a first storage module and a sensing control module. The sensing unit is used for generating a sensing current after receiving a target light. The first storage module is used for storing the sensing current. The sensing control module is used for controlling the storage of the sensing current into the first storage module. The display driving circuit comprises a data input module, a light emitting control module and a light emitting unit. The data input module is connected to the first storage module and used for receiving the sensing current from the storage module and inputting the sensing current into the light emitting control module to drive the light emitting unit to display. The application realizes the function of sensing and displaying simultaneously by deeply combining the sensing driving circuit and the display driving circuit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a pixel driving circuit and a display panel. BACKGROUND

[0002] At present, with the development of display technology, light sensors are added on the surface or inside of the display panel to realize non-visible light sensing detection represented by X-rays or other visible light sensing detection, so as to realize fingerprint identification or object detection. In particular, X-rays are used to detect objects, such as medical X-ray detection equipment, luggage inspection and security scanning, etc., which can directly use the display panel for display, greatly improving the convenience.

[0003] However, the detection result of the light sensor needs to be processed by a detection processing module, sent to a system chip, and then input to a display module through a display driving chip for display, resulting in high complexity of the system. SUMMARY

[0004] The purpose of the present application is to provide a pixel driving circuit and a display panel, which combines the sensing driving circuit and the display driving circuit in depth, so that sensing and display are executed step by step to realize the function of sensing and displaying at the same time. The detection result of the present application does not need to be processed by a detection processing module, sent to a system chip, and then displayed through a display driving circuit. Thus, the system complexity is reduced, the material cost and the use of power consumption are reduced, etc.

[0005] The present application discloses a pixel driving circuit, which comprises a display driving circuit and a sensing driving circuit in each pixel area; the sensing driving circuit comprises a sensing unit, a first storage module and a sensing control module, the sensing unit is used for generating a sensing current after receiving a target light, the first storage module is used for storing the sensing current, and the sensing control module is used for controlling the storage of the sensing current into the first storage module; the display driving circuit comprises a data input module, a light emitting control module and a light emitting unit, the data input module is connected to the first storage module, used for receiving the sensing current from the storage module and inputting the sensing current into the light emitting control module to drive the light emitting unit to display.

[0006] Optionally, the display driving circuit further comprises a second storage module, a reset module, a threshold compensation module and a first driving transistor; the data input module is connected to a first node, an input end of the first driving transistor is connected to the first node, a control end of the driving transistor is connected to a second node, and an output end of the driving transistor is connected to a third node; one end of the second storage module is connected to a power voltage end, and the other end of the second storage module is connected to the second node; one end of the light emitting unit is connected to a fourth node, and the other end of the light emitting unit is connected to a ground voltage end; two ends of the threshold compensation module are respectively connected to the second node and the third node; the reset module is used for resetting potentials of the second node and the fourth node; and the light emitting control module is used for controlling conduction between the first node and the power voltage end and conduction between the third node and the fourth node.

[0007] Optionally, the sensing control module comprises a first active switch and a second active switch; an input end of the first active switch is connected to the power voltage end, and an output end of the first active switch is connected to a fifth node; the first storage module comprises a first capacitor, one end of the first capacitor is connected to the power voltage end, and the other end of the first capacitor is connected to the fifth node; an input end of the second active switch is connected to the sensing unit, and an output end of the second active switch is connected to the fifth node; and the data input module is connected to the fifth node.

[0008] Optionally, the light emitting control module comprises a third active switch and a fourth active switch, an input end of the third active switch is connected to the power voltage end, and an output end of the third active switch is connected to the first node; an input end of the fourth active switch is connected to the third node, and an output end of the fourth active switch is connected to the fourth node; and control ends of the third active switch and the fourth active switch are respectively connected to a light emitting control signal.

[0009] Optionally, the first active switch, the third active switch and the fourth active switch are respectively P-type active switches, and the second active switch is an N-type active switch; control ends of the first active switch and the second active switch are respectively connected to the light emitting control signal; when the light emitting control signal is a first level, the third active switch and the fourth active switch are turned on to make the light emitting unit emit light, the second active switch is turned off, the sensing unit stops outputting an induced current to the first capacitor, and the first active switch is turned on to reset the fifth node; when the light emitting control signal is a second level, the first active switch, the third active switch and the fourth active switch are turned off, the second active switch is turned on, and the sensing unit outputs the induced current to the first capacitor.

[0010] Optionally, the second storage module comprises a second capacitor, one end of the second capacitor is connected to the power voltage end, and the other end of the second capacitor is connected to the second node; the data input module comprises a fifth active switch, an input end of the fifth active switch is connected to the fifth node, and an output end of the fifth active switch is connected to the first node; the reset module comprises a sixth active switch and a seventh active switch, an output end of the sixth active switch is connected to the second node, an input end of the sixth active switch is connected to a reference voltage end, an output end of the seventh active switch is connected to the fourth node, and an input end of the seventh active switch is connected to the reference voltage end; the threshold compensation module comprises an eighth active switch, an input end of the eighth active switch is connected to the second node, and an output end of the eighth active switch is connected to the third node; control ends of the sixth active switch and the seventh active switch are connected to a first scan control signal respectively; control ends of the fifth active switch and the eighth active switch are connected to a second scan control signal respectively.

[0011] Optionally, when the light-emitting control signal is at a second level, the first scan control signal and the second scan control signal are sequentially at a first level state; the fifth active switch, the sixth active switch, the seventh active switch, and the eighth active switch are P-type active switches respectively.

[0012] Optionally, the pixel driving circuit comprises a detection storage stage, a display reset stage, a data writing stage, and a light-emitting reset stage; in the detection storage stage, the light-emitting control signal is at a second level state, and the first scan control signal and the second scan control signal are at a second level state respectively; in the display reset stage, the light-emitting control signal is at a second level state, the first scan control signal is at a first level state, and the second scan control signal is at a second level state; in the data writing stage, the light-emitting control signal is at a second level state, the first scan control signal is at a second level state, and the second scan control signal is at a first level state; in the light-emitting reset stage, the light-emitting control signal is at a first level state, the first scan control signal is at a second level state, and the second scan control signal is at a second level state.

[0013] Optionally, the sensing control module comprises a first active switch, an input end of the first active switch being connected to the power voltage end, and an output end of the first active switch being connected to a fifth node; the first storage module comprises a first capacitor, one end of the first capacitor being connected to the power voltage end, and the other end of the first capacitor being connected to the fifth node; the sensing unit comprises a photosensitive active switch, an input end of the photosensitive active switch being connected to a preset voltage end, and an output end of the photosensitive active switch being connected to the fifth node; and the data input module is connected to the fifth node.

[0014] The application further discloses a display panel comprising a substrate and the pixel driving circuit.

[0015] In the application, the sensing unit in the sensing driving circuit senses the incident light and converts the light signal into a sensing current signal, which is stored in the first storage module. When the display driving circuit inputs data, the sensing current signal stored in the first storage module is input into the display driving circuit as a data signal, and the display driving circuit displays according to the sensing current signal. The sensing driving circuit and the display driving circuit are deeply combined in the application, so that sensing and displaying are performed step by step, and the function of sensing and displaying simultaneously is realized. The application does not need to set an additional data signal line, so that the sensing current signal output by the sensing driving circuit directly enters the display driving circuit, thereby saving the wiring space. Moreover, the detection result of the application does not need to be processed by the detection processing module, sent to the system chip, and then displayed by the display driving circuit. Therefore, the system complexity, material cost and use power consumption are reduced. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which are included to provide a further understanding of the embodiments of the application and constitute a part of the specification, illustrate the embodiments of the application and together with the text description serve to explain the principles of the application. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor. In the drawings:

[0017] Figure 1 is a schematic diagram of a pixel driving circuit of a first embodiment of the application;

[0018] Figure 2 is a timing diagram of the pixel driving circuit of the first embodiment of the application;

[0019] Figure 3 is a schematic diagram of a pixel driving circuit of a second embodiment of the application;

[0020] Figure 4 is a schematic diagram of a display panel of the present application;

[0021] Figure 5 is a schematic diagram of a display panel with X-ray detection function of the present application.

[0022] Wherein, 100, pixel driving circuit; 110, sensing driving circuit; 111, sensing unit; 111a, photosensitive active switch; 112, first storage module; 113, sensing control module; 120, display driving circuit; 121, data input module; 122, light-emitting control module; 123, light-emitting unit; 124, second storage module; 125, reset module; 126, threshold compensation module; 200, display panel; 210, driving circuit board; 300, flat panel detector display; 310, scintillator layer; 320, pixel driving layer; 321, substrate; A, first node; B, second node; D, third node; E, fourth node; F, fifth node; Q1, first driving transistor; T1, first active switch; T2, second active switch; T3, third active switch; T4, fourth active switch; T5, fifth active switch; T6, sixth active switch; T7, seventh active switch; T8, eighth active switch; C1, first capacitor; C2, second capacitor; VDD, power supply voltage terminal; VSS, ground voltage terminal; Vref, reference voltage terminal; Vref2, preset voltage terminal; S1, first scan control signal; S2, second scan control signal. DETAILED DESCRIPTION

[0023] It should be understood that the terms, specific structures and functional details of the disclosure used herein are only for the purpose of describing specific embodiments and are representative, but the present application can be embodied in many alternative forms, and should not be interpreted as being limited to the embodiments described herein.

[0024] In the description of the present application, the terms "first", "second" are only for the purpose of description, and should not be understood as indicating relative importance, or implying the number of the indicated technical features. Therefore, unless otherwise specified, the features limited by "first", "second" can explicitly or implicitly include one or more of the features; the meaning of "multiple" is two or more. In addition, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "vertical", "horizontal" and the like are described based on the orientation or relative position relationship shown in the drawings, and are only for the purpose of facilitating the simplified description of the present application, and should not be understood as indicating that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present application. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0025] The application will be described in detail below with reference to the accompanying drawings and optional embodiments.

[0026] Figure 1 is a schematic diagram of a pixel driving circuit of a first embodiment of the application, Figure 2 is a timing diagram of a pixel driving circuit of the first embodiment of the application; referring to Figures 1 to 2 As shown in the figure, the application discloses a pixel driving circuit 100, a pixel driving circuit 100, comprising a display driving circuit 120 and a sensing driving circuit 110 in each pixel area; the sensing driving circuit 110 comprises a sensing unit 111, a first storage module 112 and a sensing control module 113, the sensing unit 111 is used for generating a sensing current after receiving a target light, the first storage module 112 is used for storing the sensing current, and the sensing control module 113 is used for controlling the storage of the sensing current into the first storage module 112; the display driving circuit 120 comprises a data input module 121, a light-emitting control module 122 and a light-emitting unit 123, the data input module 121 is connected to the first storage module 112, used for receiving the sensing current from the storage module and inputting the sensing current into the light-emitting control module 122 to drive the light-emitting unit 123 to display.

[0027] In the application, the sensing unit 111 in the sensing driving circuit 110 senses the incident light and converts the optical signal into a sensing current signal, which is stored in the first storage module 112. When the display driving circuit 120 performs data input, the sensing current signal stored in the first storage module 112 is inputted into the display driving circuit 120 as a data signal, and the display driving circuit 120 drives the light-emitting unit 123 to display according to the sensing current signal. The application combines the sensing driving circuit 110 and the display driving circuit 120 deeply, so that the sensing and the display are executed step by step, realizing the function of sensing and displaying at the same time. The application does not need to set an additional data signal line, so that the sensing current signal outputted by the sensing driving circuit 110 directly enters the display driving circuit 120, thereby saving the wiring space. Moreover, the detection result of the application does not need to be processed by a detection processing module, sent to a system-level chip, and then displayed by the display driving circuit 120. Therefore, the system complexity, material cost and use power consumption are reduced.

[0028] It can be understood that, generally, the display panel with a photosensitive function needs to input the sensing current to the detection processing module or the detection processing chip through the sensing driving circuit 110, process the sensing current, and then input the data signal corresponding to the sensing current to the display driving circuit 120 through the data driving chip of the display driving circuit 120, so as to realize the functions of sensing and display. The present application can realize the display of the display driving circuit 120 corresponding to the size of the sensing current by adjusting the corresponding relationship between the sensing current and the data signal when the sensing current is different.

[0029] Specifically, the pixel driving circuit 100 of the present application can be applied in flat panel detection display panels and similar image detection technologies, and the light emitted by the sensing image can be directly displayed on the display panel. Specifically, it can be an X-ray flat panel detection display panel, which actively emits X-rays or uses other X-ray emitters to emit X-rays to the detected object, and the sensing unit 111 senses the X-rays or converts the X-rays into visible light to output a sensing current. The display panel displays different pictures according to the sensing current.

[0030] In an embodiment, one side (which can be referred to as a photosensitive side) of the light received by the sensing unit 111 and one side of the light emitted by the light emitting unit 123 can be set as different sides (which can be referred to as display sides), i.e., the sensing side and the display side are the front side and the back side of the display panel, respectively. Of course, the sensing side and the display side of the present application can also be arranged on the same side. The pixel driving circuit 100 of the present application can also be applied in display panels with fingerprint recognition function or face recognition function. The main point is to use the photosensitive effect of the photosensitive unit to make the fingerprint or face directly displayed through the display panel, which is a technology with a built-in sensing unit 111.

[0031] Specifically, the light emitting unit 123 in the display driving circuit 120 is generally an organic light emitting unit 123, and the sensing unit 111 of the present application can be a photosensitive diode or a photosensitive thin film transistor, etc. which has a device for converting optical signals into electrical signals.

[0032] The sensing driving circuit 110 includes a sensing unit 111, a first storage module 112, and a sensing control module 113. After the sensing unit 111 collects the optical signal and converts it into an electrical signal, the sensing control module 113 is turned on, so that the first storage module 112 stores the electrical signal. The amount of electricity stored in the first storage module 112 is generally related to the opening time of the sensing control module 113, and the amount of electricity in the first storage module 112 can be determined by controlling the opening time. By reasonably configuring the amount of electricity corresponding to different light intensities and matching the amount of electricity with the data signal used in the display driving circuit 120, the display according to the light intensity received by the sensing unit can be realized.

[0033] Specifically, the display driving circuit 120 further comprises a second storage module 124, a reset module 125, a threshold compensation module 126 and a first driving transistor Q1; the data input module 121 is connected to a first node A, an input end of the first driving transistor Q1 is connected to the first node A, a control end of the driving transistor is connected to a second node B, and an output end of the driving transistor is connected to a third node D; one end of the second storage module 124 is connected to a power voltage end VDD, and the other end of the second storage module 124 is connected to the second node B; one end of the light emitting unit 123 is connected to a fourth node E, and the other end of the light emitting unit 123 is connected to a ground voltage end VSS; two ends of the threshold compensation module 126 are respectively connected to the second node B and the third node D; the reset module 125 is used for resetting potentials of the second node B and the fourth node E; and the light emitting control module 122 is used for controlling conduction between the first node A and the power voltage end VDD and conduction between the third node D and the fourth node E.

[0034] Wherein, the first node A is connected to the data input circuit and the input end of the first driving transistor Q1 respectively, the second node B is connected to the control end of the first driving transistor Q1, and the third node D is connected to the output end of the first driving transistor Q1. The fourth node E is connected to the anode end of the light emitting unit 123.

[0035] The display driving circuit 120 in the embodiment mainly has the functions of the data input module 121, the second storage module 124, the reset module 125 and the light emitting control module 122, etc. After the data input module 121 receives the above-mentioned induced current, the second storage module 124 and the light emitting control module 122 work, so that the light emitting unit 123 displays according to the size of the induced current. For example, the larger the induced current is, the higher the light emitting brightness of the light emitting unit 123 is. The smaller the induced current is, the lower the light emitting brightness of the light emitting unit 123 is.

[0036] Of course, for the scheme of compensating the threshold value of the first driving transistor Q1 by using the external compensation technology, the above-mentioned threshold compensation module 126 can also be removed, so as to realize the threshold compensation in the display driving circuit 120 by using the external compensation circuit.

[0037] Continuing to refer to Figure 1As shown, the sensing control module 113 in the embodiment includes a first active switch T1 and a second active switch T2; the input end of the first active switch T1 is connected to the power supply voltage end VDD, and the output end of the first active switch T1 is connected to the fifth node F. The first storage module 112 includes a first capacitor C1, one end of the first capacitor C1 is connected to the power supply voltage end VDD, and the other end of the first capacitor C1 is connected to the fifth node F; the input end of the second active switch T2 is connected to the sensing unit 111, and the output end of the second active switch T2 is connected to the fifth node F; the data input module 121 is connected to the fifth node F.

[0038] Since one end of the first capacitor C1 is connected to the power supply voltage end VDD, it is always in the power supply voltage state in different stages of sensing and display. Therefore, the voltage change of the first node A connected to the other end of the first capacitor C1 corresponds to the change in the amount of current flowing into the sensing unit 111. The induced current of the sensing unit 111 is in the negative direction, that is, the positive charge flows from the fifth node F to the sensing unit 111, which can be regarded as the voltage output from the fifth node F, corresponding to setting the voltage value of the fifth node F as Vse. The smaller the light intensity is, the smaller the induced current is, and the larger the Vse is. The larger the Vse is, the higher the brightness of the light emitting unit 123 is, the larger the light intensity is, the larger the induced current is, and the smaller the Vse is. The smaller the Vse is, the lower the brightness of the light emitting unit 123 is.

[0039] The first active switch T1 has a reset function, when the first active switch T1 is turned on, the two ends of the first capacitor C1 are respectively connected to the power supply voltage end VDD, so that the potential at the two ends of the capacitor is configured as the power supply voltage potential. When the second active switch T2 is turned on, the first active switch T1 is in the off state, and the voltage value of the first node A is discharged under the action of the second active switch T2, and the discharge size depends on the light intensity sensed by the light sensing unit and the induced current. The higher the sensed light intensity is, the larger the induced current is, so that the fifth node F of the first capacitor C1 discharges more, and the Vse is smaller. Conversely, the lower the sensed light intensity is, the larger the Vse is.

[0040] The sensing driving circuit 110 of the present application can be applied to a direct conversion flat panel detector or an indirect conversion flat panel detector. The basic principle is that through a flash crystal coating or amorphous selenium layer, combined with a thin film transistor or an external bias electric field, the light sensing unit generates an induced current proportional to the light intensity. When the second active switch T2 is turned on, the data of the induced current is stored in the fifth node F of the first capacitor C1, and subsequently there is a data input module 121 to read the voltage value on the fifth node F.

[0041] Specifically, the light emitting control module 122 comprises a third active switch T3 and a fourth active switch T4, an input end of the third active switch T3 is connected to the power voltage end VDD, an output end of the third active switch T3 is connected to the first node A; an input end of the fourth active switch T4 is connected to the third node D, an output end of the fourth active switch T4 is connected to the fourth node E; a control end of the third active switch T3 and a control end of the fourth active switch T4 are respectively connected to the light emitting control signal.

[0042] The light emitting control signal drives the third active switch T3 and the fourth active switch T4 to be turned on or turned off, controls whether the light emitting unit 123 is connected to the power voltage end VDD and the ground voltage end VSS, thereby controlling whether the light emitting unit 123 emits light, and regulates the current flowing through the light emitting unit 123 according to the gate voltage of the first drive transistor Q1 to realize different gray-scale brightness display. For the light emitting unit 123, when data is not written, the light emitting unit 123 needs to be made not to emit light by the light emitting control signal to avoid displaying an incorrect brightness.

[0043] In the embodiment, sensing and light emitting need to be performed in different time periods, that is, sensing is completed first and then display is performed. The third active switch T3 and the fourth active switch T4 mainly control whether the light emitting unit 123 emits light, when the third active switch T3 and the fourth active switch T4 are turned off, the light emitting unit 123 does not emit light, at this time, the photosensitive unit receives light and stores the sensing current in the first capacitor C1. When the third active switch T3 and the fourth active switch T4 are turned on, the light emitting unit 123 emits light, at this time, the photosensitive unit receives light but does not transmit the sensing current to the first capacitor C1. Wherein, after the third active switch T3 and the fourth active switch T4 are turned on, the data input circuit, the reset module 125 and the threshold compensation module 126 also need to work, so that the third active switch T3 and the fourth active switch T4 drive the light emitting unit 123 to emit light.

[0044] In an embodiment, the control end of the first active switch T1, the control end of the second active switch T2, the control end of the third active switch T3 and the control end of the fourth active switch T4 are respectively connected to the light emitting control signal. The first active switch T1, the third active switch T3 and the fourth active switch T4 are respectively P-type active switches, and the second active switch T2 is an N-type active switch. The first drive transistor Q1 of the application is a P-type thin film transistor.

[0045] When the light emitting control signal is the first level, the third active switch T3 and the fourth active switch T4 are turned on so that the light emitting unit 123 emits light, the second active switch T2 is turned off, the sensing unit 111 stops outputting the induced current to the first capacitor C1, and the first active switch T1 is turned on so that the fifth node F is reset. When the light emitting control signal is the second level, the first active switch T1, the third active switch T3, and the fourth active switch T4 are turned off, the second active switch T2 is turned on, and the sensing unit 111 outputs the induced current to the first capacitor C1.

[0046] The first level is generally a logic low level signal, which is used to make the N-type active switch in the off state and the P-type active switch in the on state. The second level is generally a logic high level signal, which is used to make the N-type active switch in the on state and the P-type active switch in the off state. The N-type active switch can use a-Si or oxide semiconductor as the active layer of the active switch. The P-type active switch uses LTPS process as the main process.

[0047] In the embodiment, the sensing period and the light emitting period are adjusted by the light emitting control signal, and only one control signal is needed, that is, the control of the first active switch T1 and the second active switch T2 in the sensing driving circuit 110 is completed. By configuring the first active switch T1 and the second active switch T2 as different types of active switches, the reset and readout of the light sensing unit are realized.

[0048] Specifically, the display driving circuit 120 of the present application can be exemplified by a 7T1C circuit, but it does not mean that the display driving circuit 120 of the present application is limited to the circuit design of 7T1C. Other display driving circuits 120 drive the light emitting unit 123 and are suitable for the circuit design of the light emitting control signal, and also belong to the protection scope of the present application.

[0049] Specifically, the second storage module 124 includes a second capacitor C2, one end of the second capacitor C2 is connected to the power voltage end VDD, and the other end of the second capacitor C2 is connected to the second node B. The data input module 121 includes a fifth active switch T5, an input end of the fifth active switch T5 is connected to the fifth node F, and an output end of the fifth active switch T5 is connected to the first node A. The reset module 125 includes a sixth active switch T6 and a seventh active switch T7, an output end of the sixth active switch T6 is connected to the second node B, an input end of the sixth active switch T6 is connected to a reference voltage end Vref, an output end of the seventh active switch T7 is connected to the fourth node E, and an input end of the seventh active switch T7 is connected to the reference voltage end Vref. The threshold compensation module 126 includes an eighth active switch T8, an input end of the eighth active switch T8 is connected to the second node B, and an output end of the eighth active switch T8 is connected to the third node D; control ends of the sixth active switch T6 and the seventh active switch T7 are respectively connected to a first scan control signal S1; and control ends of the fifth active switch T5 and the eighth active switch T8 are respectively connected to a second scan control signal S2.

[0050] Among them, the fifth active switch T5, the sixth active switch T6, the seventh active switch T7 and the eighth active switch T8 of the present application are P-type active switches, which are turned on at a logic low level and turned off at a logic high level. The first scan control signal S1 and the second scan control signal S2 are row scan driving signals, and only one logic low level pulse appears in a frame time. When the first scan control signal S1 is at a logic low level, the sixth active switch T6 and the seventh active switch T7 are turned on, so that the potential of the second node B and the potential of the fourth node E are reset, that is, the gate of the first driving transistor Q1 and the anode of the light emitting unit 123 are controlled to be reset. When the second scan control signal S2 is at a logic low level, the fifth active switch T5 is turned on, so that the induced current can be written. And the eighth active switch T8 is turned on, so that the second node B and the third node D are electrically connected, and the threshold compensation of the first driving transistor Q1 is realized.

[0051] When the light emitting control signal is at the second level, the first scan control signal S1 and the second scan control signal S2 are sequentially at the first level state. The first scan control signal S1 and the second scan control signal S2 are usually provided by different gate driving units of the same gate driving circuit, and have the characteristics that the pulse widths are equal. And the first scan control signal S1 and the second scan control signal S2 are opened in front and back order, and a certain interval is set for the first scan control signal S1 and the second scan control signal S2, so as to allocate data writing time for each row of light emitting units 123.

[0052] The power voltage terminal VDD outputs a power voltage signal, which provides a forward voltage signal for the light emitting unit 123. The power voltage signal generally enters the light emitting unit 123 from the anode terminal of the light emitting unit 123, and the current size entering the light emitting unit 123 is controlled by the data signal, thereby controlling the brightness of the light emitting unit 123. The cathode terminal of the light emitting unit 123 is generally connected to the ground voltage terminal VSS, which provides a ground voltage signal for the light emitting unit 123. The reference voltage terminal Vref generally inputs a reference voltage signal, which is used for resetting the anode terminal of the light emitting unit 123 and the gate terminal of the first driving transistor Q1.

[0053] Specifically, the pixel driving circuit 100 includes a detection storage stage, a display reset stage, a data writing stage, and a light emitting reset stage.

[0054] In the detection storage stage, the light emitting control signal is in the second level state, and the first scan control signal S1 and the second scan control signal S2 are respectively in the second level state. At this time, the second active switch T2 is turned on, the light sensing unit is discharged, so that the Vse of the fifth node F changes, and the voltage corresponding to the light intensity is stored in the fifth node F.

[0055] In the display reset stage, the light emitting control signal is in the second level state, the first scan control signal S1 is in the first level state, and the second scan control signal S2 is in the second level state. At this time, the second active switch T2 still maintains the on state, so that the light sensing unit continues to discharge, and the time sum of the corresponding detection storage stage and display reset stage is the light sensing detection time. The light sensing detection time can be controlled by reasonably setting the time of the two stages, especially the time of the detection storage stage. Relatively speaking, the longer the light sensing detection time is, the longer the detection time is, and the higher the detection precision is. In the display reset stage, the first scan control signal S1 is in the first level state, so that the potential of the second node B and the potential of the fourth node E are also reset synchronously in the sensing process of the sensing driving circuit 110, thereby preparing for data signal writing.

[0056] In the data writing stage, the light emitting control signal is in the second level state, the first scan control signal S1 is in the second level state, and the second scan control signal S2 is in the first level state. When the second scan control signal S2 is in the first level state, the first drive transistor Q1 and the fifth active switch T5 and the eighth active switch T8 are turned on at the same time, a path is formed through the fifth active switch T5, the first drive transistor Q1 and the eighth active switch T8, and Vse is written into the first drive transistor Q1 gate and threshold compensation function is realized. A certain time interval can be reserved between the data writing stage and the display reset stage, so that the detection time is increased, and the sensing unit is no longer written in when entering the data writing stage.

[0057] In the light emitting reset stage, the light emitting control signal is in the first level state, the first scan control signal S1 is in the second level state, and the second scan control signal S2 is in the second level state. After the light emitting control signal is in the first level state, the first active switch T1 in the sensing drive circuit 110 is turned on, so that the potential of the fifth node F is reset, the second active switch T2 is cut off, the sensing unit 111 no longer reads the sensing current, and waits for the next frame detection storage stage to start. When the second scan control signal S2 is in the second level state, the fifth active switch T5 and the eighth active switch T8 are both in the cut-off state, and Vse stored in the second capacitor C2 is used to control the gate of the first drive transistor Q1 to drive the light emitting unit 123 to display.

[0058] Specifically, when Vse of the fifth node F is lower, the gate voltage written into the first drive transistor Q1 is lower, and the absolute value of the gate-source voltage Vgs (Vgs=Vg_Q1-VDD) of the first drive transistor Q1 is larger, and Vg_Q1 represents the voltage of the gate of the first drive transistor Q1. Taking the voltage of the fifth node F as Vse as an example, the compensation principle of the display drive circuit 120 of the present application, the gate voltage Vg_Q1 written into the first drive transistor Q1 is Vse+Vth, according to the current formula: Vgs=Vse+Vth-VDD can be obtained: . Where μ p is the electron mobility, C ox is the unit area capacitance of the TFT device, and W / L represents the ratio of the channel width to the length of the TFT. According to the formula, when Vse is smaller, the current I d output by the first drive transistor Q1 is larger, and the brightness of the light emitting unit 123 is higher, so that the sensing structure is realized.

[0059] Figure 3 is a schematic diagram of a pixel drive circuit of a second embodiment of the present application, referring to Figure 3As shown, the present application also discloses another pixel driving circuit, the main design of the pixel driving circuit 100 is the same as the first embodiment, and will not be repeated here. The difference is that the light sensing unit is replaced by the second active switch T2, so that the design of the light sensing diode is removed.

[0060] Specifically, the sensing unit 111 includes a light sensing active switch 111a, the input end of the light sensing active switch 111a is connected to a preset voltage end Vref2, and the output end of the light sensing active switch 111a is connected to the fifth node F; the data input module 121 is connected to the fifth node F. The preset voltage end Vref2 can issue a low voltage reference signal, which can be adjusted according to actual conditions, or as a compensation signal input end. For example, when the sensitivity of the light sensing thin film transistor to light is not enough, or when the voltage of the fifth node is not fully released, the voltage value of the low voltage reference signal is changed to compensate for the sensing current as a data signal.

[0061] In this embodiment, the sensing unit 111 uses a light sensing thin film transistor, and the a-Si or oxide semiconductor formed active layer channel in the light sensing thin film transistor is sensitive to light. By using the different drain currents of the light sensing thin film transistor under different light intensities, the light intensity can be sensed. When the light intensity increases, the current of the light sensing active switch 111a increases, so that the voltage of Vse decreases, thereby realizing that the higher the light brightness, the higher the brightness of the light emitting unit 123.

[0062] Figure 4 is a schematic view of the display panel of the present application, referring to Figure 4 As shown, the present application also discloses a display panel, the display panel 200 includes a substrate and the pixel driving circuit 100 in any one of the above embodiments, and the pixel driving circuit 100 is arranged on the substrate. Of course, the display panel also includes a packaging layer, a color filter layer and other film layers arranged on the substrate, and the pixel driving circuit 100 drives the light emitting unit 123 to work, and the light emitting unit 123 emits light from the packaging layer, the color filter layer to be displayed. At the same time, the pixel driving circuit 100 is also connected with a driving circuit board 210, and the driving circuit board 210 is provided with a timing controller, a sensing controller and other chips to drive the pixel driving circuit 100 to realize sensing of target light and display of the picture. It can be understood that the sensing unit 111 of the display panel can be used for fingerprint recognition, air touch and other light sensing control or light sensing detection.

[0063] Figure 5 is a schematic view of the display panel with X-ray detection function of the present application, referring to Figure 5As shown, the application also discloses a display panel with X-ray detection function, which can also be called flat panel detector display. The flat panel detector display 300 comprises a scintillator layer 310 and a pixel driving layer 320. The scintillator layer is used to convert X-rays into visible light. The pixel driving layer 320 comprises a substrate 321 and a plurality of pixel driving circuits 100 arranged on the substrate 321. The pixel driving layer 320 comprises a plurality of pixel areas arranged in an array. Each pixel area is provided with a pixel driving circuit 100. Each pixel area is provided with a light emitting unit 123 and a sensing unit 111. The light emitting unit 123 and the sensing unit 111 are arranged in the same layer. The flat panel detector display combines the flat panel detector and the display, so that the image information detected by the flat panel detector can be directly displayed by the display.

[0064] It should be noted that the inventive concept of the application can form a very large number of embodiments, but the length of the application file is limited and cannot list all the embodiments. Therefore, under the premise of not conflicting, the above-described embodiments or technical features can be combined to form new embodiments. The combination of each embodiment or technical feature will enhance the original technical effect.

[0065] The above is a further detailed description of the application in combination with specific optional embodiments, and the specific implementation of the application cannot be limited to these descriptions. For ordinary skilled persons in the art to which the application belongs, without departing from the concept of the application, a number of simple deductions or substitutions can be made, which should be considered as falling within the protection scope of the application.

Claims

1. A pixel driving circuit, characterized by comprising: The display driving circuit and the sensing driving circuit are respectively arranged in each pixel region; The sensing driving circuit comprises a sensing unit, a first storage module and a sensing control module, the sensing unit is used for generating a sensing current after receiving a target light, the first storage module is used for storing the sensing current, and the sensing control module is used for controlling the sensing current to be stored into the first storage module; The display driving circuit comprises a data input module, a light emitting control module and a light emitting unit, the data input module is connected to the first storage module and used for receiving the sensing current from the first storage module and inputting the sensing current into the light emitting control module to drive the light emitting unit to display.

2. The pixel driving circuit according to claim 1, characterized in that, The display driving circuit further comprises a second storage module, a reset module, a threshold compensation module and a first driving transistor; The data input module is connected to a first node, an input end of the first driving transistor is connected to the first node, a control end of the first driving transistor is connected to a second node, and an output end of the first driving transistor is connected to a third node; One end of the second storage module is connected to a power voltage end, and the other end of the second storage module is connected to the second node; One end of the light emitting unit is connected to a fourth node, and the other end of the light emitting unit is connected to a ground voltage end; Two ends of the threshold compensation module are respectively connected to the second node and the third node; The reset module is used for resetting potentials of the second node and the fourth node; The light emitting control module is used for controlling conduction between the first node and the power voltage end and conduction between the third node and the fourth node.

3. The pixel driving circuit of claim 2, wherein, The sensing control module comprises a first active switch and a second active switch, an input end of the first active switch is connected to the power voltage end, and an output end of the first active switch is connected to a fifth node; The first storage module comprises a first capacitor, one end of the first capacitor is connected to the power voltage end, and the other end of the first capacitor is connected to the fifth node; An input end of the second active switch is connected to the sensing unit, and an output end of the second active switch is connected to the fifth node; The data input module is connected to the fifth node.

4. The pixel driving circuit of claim 3, wherein, The light emitting control module comprises a third active switch and a fourth active switch, an input end of the third active switch is connected to the power voltage end, and an output end of the third active switch is connected to the first node; An input end of the fourth active switch is connected to the third node, and an output end of the fourth active switch is connected to the fourth node; Control ends of the third active switch and the fourth active switch are respectively connected to a light emitting control signal.

5. The pixel driving circuit of claim 4, wherein, The first active switch, the third active switch and the fourth active switch are respectively P-type active switches, and the second active switch is an N-type active switch; Control ends of the first active switch and the second active switch are respectively connected to the light emitting control signal. When the light emitting control signal is at a first level, the third active switch and the fourth active switch are turned on so that the light emitting unit emits light, the second active switch is turned off, the sensing unit stops outputting the induced current to the first capacitor, and the first active switch is turned on so that the fifth node is reset; When the light emitting control signal is at a second level, the first active switch, the third active switch and the fourth active switch are turned off, the second active switch is turned on, and the sensing unit outputs the induced current to the first capacitor.

6. The pixel driving circuit of claim 5, wherein, The second storage module includes a second capacitor, one end of the second capacitor is connected to the power voltage end, and the other end of the second capacitor is connected to the second node; The data input module includes a fifth active switch, an input end of the fifth active switch is connected to the fifth node, and an output end of the fifth active switch is connected to the first node; The reset module includes a sixth active switch and a seventh active switch, an output end of the sixth active switch is connected to the second node, an input end of the sixth active switch is connected to a reference voltage end, an output end of the seventh active switch is connected to the fourth node, and an input end of the seventh active switch is connected to the reference voltage end; The threshold compensation module includes an eighth active switch, an input end of the eighth active switch is connected to the second node, and an output end of the eighth active switch is connected to the third node; Control ends of the sixth active switch and the seventh active switch are respectively connected to a first scan control signal; Control ends of the fifth active switch and the eighth active switch are respectively connected to a second scan control signal.

7. The pixel driving circuit of claim 6, wherein, When the light emitting control signal is at the second level, the first scan control signal and the second scan control signal are sequentially at a first level state; The fifth active switch, the sixth active switch, the seventh active switch and the eighth active switch are respectively P-type active switches.

8. The pixel driving circuit of claim 6, wherein, The pixel driving circuit includes a detection storage stage, a display reset stage, a data writing stage and a light emitting reset stage; In the detection storage stage, the light emitting control signal is at a second level state, and the first scan control signal and the second scan control signal are respectively at a second level state; In the display reset stage, the light emitting control signal is at a second level state, the first scan control signal is at a first level state, and the second scan control signal is at a second level state; In the data writing stage, the light emitting control signal is at a second level state, the first scan control signal is at a second level state, and the second scan control signal is at a first level state; In the light emitting reset stage, the light emitting control signal is at a first level state, the first scan control signal is at a second level state, and the second scan control signal is at a second level state.

9. The pixel driving circuit of claim 2, wherein, The sensing control module includes a first active switch, an input end of the first active switch is connected to the power voltage end, and an output end of the first active switch is connected to the fifth node; The first storage module comprises a first capacitor, one end of the first capacitor is connected to the power voltage terminal, and the other end of the first capacitor is connected to the fifth node; The sensing unit comprises a photosensitive active switch, an input end of the photosensitive active switch is connected to a preset voltage terminal, and an output end of the photosensitive active switch is connected to the fifth node; The data input module is connected to the fifth node.

10. A display panel, characterized by, The display panel comprises a substrate and a pixel driving circuit as claimed in any one of claims 1 to 9, and the pixel driving circuit is arranged on the substrate.

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