Pixel circuit and display panel

Abstract

The application provides a pixel circuit and a display panel. The pixel circuit comprises a light-emitting module, a driving switch tube, an energy storage module, a reset circuit, a threshold compensation circuit, a data writing circuit and a light-emitting circuit. The first connection end of the driving switch tube is used for receiving a driving voltage, and the second connection end is electrically connected with the light-emitting module. The first end of the energy storage module is electrically connected with the control end of the driving switch tube. The reset circuit is used for connecting the first end of the energy storage module to the ground and resetting the voltage of the second end of the energy storage module to the driving voltage in the reset stage. The threshold compensation circuit is used for connecting the second end of the energy storage module to the ground and providing the driving voltage to the first end of the energy storage module in the threshold compensation stage, so that the potential of the first end of the energy storage module changes to a first voltage. The data writing circuit is used for inputting a data voltage and providing the data voltage to the second end of the energy storage module in the light-emitting stage. The light-emitting circuit is used for making the light-emitting module emit light in the light-emitting stage.

Description

Technical Field

[0001] This application relates to the field of display technology, and more particularly to a pixel circuit and a display panel. Background Technology

[0002] OLED (Organic Light-Emitting Diode) is a device that generates electroluminescence using a multilayer organic thin-film structure. It is easy to manufacture and requires only low driving voltage, making it particularly prominent in flat panel display applications. Compared to LCD displays, OLED displays are thinner, lighter, brighter, consume less power, have faster response times, higher resolution, better flexibility, and higher luminous efficiency, meeting consumers' evolving demands for display technology.

[0003] In an OLED display panel, the light-emitting elements in each pixel unit are driven by the current generated by a thin-film transistor (TFT) in its saturation state. Due to limitations in the manufacturing process, especially the poor uniformity and drift of the threshold voltage Vth of the TFTs manufactured using low-temperature polysilicon (LTPS) technology, the threshold voltage Vth of the TFTs in different pixel units is inconsistent. Therefore, when the same data voltage is input, the inconsistent threshold voltage Vth will lead to inconsistent driving currents in different pixel units, resulting in poor brightness uniformity of the display panel. Summary of the Invention

[0004] In view of this, the main purpose of this application is to propose a pixel circuit and a display panel, which aims to solve the problem of poor brightness uniformity of the display panel caused by the inconsistent threshold voltage Vth of the driving switching transistor in the light-emitting elements of each pixel unit in the existing OLED display panel.

[0005] To achieve the above objectives, a first aspect of this application provides a pixel circuit that operates sequentially in a reset phase, a threshold compensation phase, and a light-emitting phase during the display cycle of one frame. The pixel circuit includes a light-emitting module, a driving switch, an energy storage module, a reset circuit, a threshold compensation circuit, a data writing circuit, and a light-emitting circuit. The light-emitting module includes a first terminal and a second terminal, with the first terminal grounded. The driving switch includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal receives a driving voltage, and the second connection terminal is electrically connected to the second terminal of the light-emitting module. The energy storage module includes a first terminal and a second terminal, with the first terminal electrically connected to the control terminal of the driving switch. The energy storage module is located in the reset circuit, which is used to conduct during the reset phase, grounding the first terminal of the energy storage module and providing the driving voltage to the second terminal of the energy storage module to reset the voltage at the second terminal to the driving voltage. The driving switch and the energy storage module are connected in series in the threshold compensation circuit. The threshold compensation circuit is used to turn on during the threshold compensation phase, disconnect the electrical connection between the first terminal of the energy storage module and ground, and ground the second terminal of the energy storage module. This allows the driving voltage to be provided to the first terminal of the energy storage module through the driving switch, thereby causing the potential of the first terminal of the energy storage module to change to a first voltage, where the first voltage is the difference between the driving voltage and the threshold voltage of the driving switch. The data writing circuit is electrically connected to the second terminal of the energy storage module. This data writing circuit is used to turn on during the light emission phase, providing a data voltage to the second terminal of the energy storage module. This allows the energy storage module to adjust the potential of the control terminal of the driving switch to a second voltage based on its voltage holding characteristics, where the second voltage is the sum of the first voltage and the data voltage. The driving switch and the light emission module are connected in series in the light emission circuit. The light emission circuit is used to turn on during the light emission phase, allowing the driving voltage to be provided to the light emission module through the driving switch, thereby causing the light emission module to emit light. The driving switch adjusts the brightness of the light-emitting module based on the driving voltage received at its first connection terminal and the second voltage received at its control terminal.

[0006] The pixel circuit provided in this application adjusts the potential of the first terminal of the energy storage module to a first voltage through a threshold compensation circuit during the threshold compensation stage, and provides a data voltage to the second terminal of the energy storage module through a data writing circuit during the light emission stage. This allows the energy storage module to adjust the potential of the control terminal of the driving switch to a second voltage based on its voltage holding characteristics. Consequently, the driving switch adjusts the light emission brightness of the light emission module based on the driving voltage received at its first connection terminal and the second voltage received at its control terminal. This can compensate for the threshold voltage of the driving switch, making the light emission brightness of the light emission module independent of the threshold voltage. This solves the problem of uneven display brightness caused by different threshold voltages of the driving switches in different pixel circuits.

[0007] Optionally, the pixel circuit further includes a first switching transistor located in the reset circuit. The first switching transistor includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the first switching transistor is grounded, and the second connection terminal of the first switching transistor is electrically connected to the first terminal of the energy storage module. During the reset phase, the first switching transistor is turned on based on a first scan signal received by its control terminal, so that the first terminal of the energy storage module is grounded through the turned-on first switching transistor.

[0008] Optionally, the pixel circuit further includes a second switch located in the reset circuit. The second switch includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the second switch is used to receive the driving voltage, and the second connection terminal of the second switch is electrically connected to a second terminal of the energy storage module. During the reset phase, the first switch is turned on based on a first scan signal received by its control terminal, and the second switch is turned on based on a second scan signal received by its control terminal, thereby turning on the reset circuit.

[0009] Optionally, the driving voltage is high, and the driving switch is a low-level on switch. The pixel circuit further includes a third switch located in the threshold compensation loop. The third switch includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the third switch is grounded, and the second connection terminal of the third switch is electrically connected to the second terminal of the energy storage module. During the threshold compensation stage, the third switch is turned on based on a third scan signal received at its control terminal, causing the second terminal of the energy storage module to be grounded through the on-state third switch. This allows the energy storage module to adjust the potential of the control terminal of the driving switch to a third voltage based on its voltage holding characteristics, thereby turning on the driving switch. The third voltage is the difference between the ground potential and the driving voltage.

[0010] Optionally, the pixel circuit further includes a fourth switch located in the threshold compensation loop. Each fourth switch includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the fourth switch is electrically connected to the second connection terminal of the driving switch, and the second connection terminal of the fourth switch is electrically connected to the first terminal of the energy storage module. During the threshold compensation stage, the third switch is turned on based on a third scan signal received at its control terminal, the driving switch is turned on based on the third voltage received at its control terminal, and the fourth switch is turned on based on a fourth scan signal received at its control terminal, thereby activating the threshold compensation loop.

[0011] Optionally, the pixel circuit further includes a fifth switching transistor located in the light-emitting circuit. The fifth switching transistor includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the fifth switching transistor is electrically connected to the second connection terminal of the driving switching transistor, and the second connection terminal of the fifth switching transistor is electrically connected to the second terminal of the light-emitting module. During the light-emitting phase, the driving switching transistor is turned on based on the second voltage received at its control terminal, and the fifth switching transistor is turned on based on the fifth scan signal received at its control terminal, thereby turning on the light-emitting circuit.

[0012] Optionally, the pixel circuit further includes a data write switch located in the data write loop. The data write switch includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the data write switch is used to receive a data voltage, and the second connection terminal of the data write switch is electrically connected to the second terminal of the energy storage module. During the light emission phase, the data write switch is turned on based on a data write control signal received at its control terminal, thereby enabling the second terminal of the energy storage module to receive the data voltage through the turned-on data write switch.

[0013] Optionally, the pixel circuit further includes a voltage follower located in the data writing loop. The voltage follower includes an input terminal and an output terminal. The input terminal of the voltage follower is electrically connected to the second connection terminal of the data writing switch, and the output terminal of the voltage follower is electrically connected to the second terminal of the energy storage module.

[0014] Optionally, the pixel circuit further includes a data write control circuit for generating the data write control signal. The data write control circuit includes a sixth switch, a comparator, and a D flip-flop. The sixth switch includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the sixth switch is electrically connected to a first terminal of the energy storage module. The comparator includes a non-inverting input terminal, an inverting input terminal, and an output terminal. The non-inverting input terminal of the comparator is electrically connected to the second connection terminal of the sixth switch, and the inverting output terminal of the comparator is grounded. The comparator outputs a corresponding comparison signal based on the relationship between the voltage at the non-inverting input terminal and the voltage at the inverting input terminal. The D flip-flop includes a D input, a clock signal input, and a Q output. The D input receives a constant trigger voltage. The clock signal input is electrically connected to the comparator's output and receives the comparison signal output by the comparator. The Q output is electrically connected to the data write switch. The D flip-flop outputs the trigger voltage through its Q output in response to a level change in the comparison signal. During the light-emitting phase, the sixth switch is turned on based on a sixth scan signal received at its control terminal. This causes the comparator to connect electrically to the first terminal of the energy storage module via the turned-on sixth switch, resulting in a change in the comparison signal output by the comparator from low to high. Consequently, the D flip-flop outputs the trigger voltage through its Q output in response to this change. The data write control signal output by the data write control circuit is the trigger voltage output by the Q output of the D flip-flop.

[0015] A second aspect of this application also provides a display panel, the display panel including the pixel circuit, data driver, and scan driver described in the first aspect. The data driver is used to generate data voltage and output it to the pixel circuit. The scan driver is used to generate a plurality of scan signals and output them to the pixel circuit to drive the pixel circuit to sequentially operate in a reset phase, a threshold compensation phase, and a light emission phase during the display cycle of one frame.

[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the existing pixel circuit structure;

[0018] Figure 2 This is a schematic diagram of the pixel circuit provided in an embodiment of this application;

[0019] Figure 3 yes Figure 2 The diagram shown illustrates the timing of the pixel circuit during the display cycle of one frame.

[0020] Figure 4 yes Figure 2 The diagram shows the pixel circuit during the reset phase J1.

[0021] Figure 5 yes Figure 2 The diagram shows the pixel circuit in the threshold compensation stage J2.

[0022] Figure 6 yes Figure 2 The diagram shows the pixel circuit in the light-emitting stage J3.

[0023] Figure 7 This is a schematic diagram of the structure of the display panel provided in the embodiment of this application.

[0024] The annotations in the attached figures are explained as follows:

[0025] Pixel circuits 100, 100'

[0026] Light-emitting module L

[0027] Drive switch M1, energy storage module C, reset circuit H1, threshold compensation circuit H2, light-emitting circuit H3, drive voltage VCC, data voltage Vdata, trigger voltage VCR, first voltage V1, second voltage V2, third voltage V3

[0028] First end G

[0029] Second terminal N: First switch T1, Second switch T2, Third switch T3, Fourth switch T4, Data write switch M2, Fifth switch T5, Sixth switch T6, Data write control circuit 10, Data write loop 20, Voltage follower U1, Comparator U2, D flip-flop U3, Scan signal S0, First scan signal S1, Second scan signal S2, Third scan signal S3, Fourth scan signal S4, Fifth scan signal S5, Sixth scan signal S6, Reset stage J1, Threshold compensation stage J2

[0030] Light-emitting stage J3

[0031] Display Panel 1

[0032] Substrate 1000

[0033] Display area 1001

[0034] Non-display area 1002

[0035] Data Drive 120

[0036] Scan drive 110

[0037] Scan line 111

[0038] Data cable 121

[0039] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0041] In the description of this application, it should be noted that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] Please see Figure 1 , Figure 1 It is an existing 2T1C structure pixel circuit 100', which includes a scanning switch transistor T0, a driving switch transistor M1, an energy storage module C, and a light-emitting module L.

[0043] The pixel circuit 100' is used to drive the light-emitting module L to emit light. The first terminal of the light-emitting module L is grounded. The source of the driving switch M1 receives the driving voltage VCC, the drain of the driving switch M1 is electrically connected to the second terminal of the light-emitting module L, the gate of the driving switch M1 is electrically connected to the source of the scan switch T0, the source of the scan switch T0 receives the data voltage Vdata, and the gate of the scan switch T0 receives the scan signal S0. The first terminal of the energy storage module C is electrically connected to the gate of the driving switch M1, and the second terminal of the energy storage module C is electrically connected to the second terminal of the light-emitting module L. For example, when the scan signal is an enable signal, the scan switch T0 is turned on, and the data voltage Vdata on the data line 121 charges the energy storage module C through the scan switch T0 to adjust the potential of the first terminal of the energy storage module C to the data voltage Vdata. The drive switch M1 drives the light-emitting module L to emit light based on the data voltage Vdata received at its gate and the drive voltage VCC received at its source. At this time, the source-gate voltage Vsg of the drive switch M1 = Vs - Vg = VCC - Vdata, and the drive current Ids flowing through the light-emitting module L has the following relationship with the source-gate voltage Vsg of the drive switch M1:

[0044] Ids=(K / 2)(Vsg-Vth) 2 = (K / 2)(VCC-Vdata-Vth) 2

[0045] Where K = Cox × μ × W / L, Cox is the gate capacitance per unit area; μ is the channel electron mobility; W / L is the width-to-length ratio of the channel of the driving switch M1; and Vth is the threshold voltage Vth of the driving switch M1.

[0046] It is easy to understand that the brightness of the light-emitting module L is directly proportional to the driving current Ids flowing through it, that is, it is related to the data voltage Vdata, the driving voltage VCC, and the threshold voltage Vth of the driving switch M1. Since the uniformity of the threshold voltage Vth of the driving switch M1 is relatively poor—that is, the threshold voltage Vth of the driving switch M1 is inconsistent in different pixel circuits 100'—when the same data voltage is input, the inconsistent threshold voltage Vth will lead to inconsistent driving current Ids in different pixel circuits 100', resulting in poor brightness uniformity of the display panel.

[0047] In view of this, please refer to Figure 2In order to solve the problem of poor brightness uniformity of the display panel caused by the poor uniformity of the threshold voltage Vth of the driving switch M1 of the existing pixel circuit 100', this application provides a pixel circuit 100, which operates sequentially in the reset stage J1, the threshold compensation stage J2 and the light emission stage J3 in the display cycle of one frame.

[0048] The pixel circuit 100 includes a light-emitting module L, a driving switch M1, an energy storage module C, a reset circuit H1, a threshold compensation circuit H2, a light-emitting circuit H3, and a data writing circuit H4.

[0049] The light-emitting module L includes a first end and a second end, with the first end of the light-emitting module L being grounded.

[0050] The driving switch M1 includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the driving switch M1 is used to receive the driving voltage VCC, and the second connection terminal of the driving switch M1 is electrically connected to the second terminal of the light-emitting module L.

[0051] The energy storage module C includes a first terminal G and a second terminal N. The first terminal G of the energy storage module C is electrically connected to the control terminal of the drive switch M1.

[0052] The energy storage module C is located in the reset circuit H1. The reset circuit H1 is used to turn on J1 during the reset phase, ground the first terminal G of the energy storage module C, and provide the driving voltage VCC to the second terminal N of the energy storage module C, so as to reset the voltage of the second terminal N of the energy storage module C to the driving voltage VCC.

[0053] The driving switch M1 and the energy storage module C are connected in series in the threshold compensation circuit H2. The threshold compensation circuit H2 is used to turn on J2 during the threshold compensation stage, disconnect the connection between the first terminal G of the energy storage module C and ground, and ground the second terminal N of the energy storage module C, so that the driving voltage VCC is provided to the first terminal G of the energy storage module C through the driving switch M1, thereby causing the potential of the first terminal G of the energy storage module C to change to the first voltage V1, wherein the first voltage V1 is the difference between the driving voltage VCC and the threshold voltage Vth of the driving switch M1, i.e., V1 = VCC - Vth.

[0054] The data writing circuit H4 is electrically connected to the second terminal N of the energy storage module C. The data writing circuit H4 is used to turn on J3 during the light-emitting phase, inputting a data voltage Vdata and providing it to the second terminal N of the energy storage module C. This allows the energy storage module C to adjust the potential of the control terminal of the driving switch M1 to a second voltage V2 based on its voltage holding characteristics. The second voltage V2 is the sum of the first voltage V1 and the data voltage Vdata.

[0055] V2=V1+Vdata=VCC-Vth+Vdata.

[0056] The driving switch M1 is connected in series with the light-emitting module L in the light-emitting circuit H3. The light-emitting circuit H3 is used to turn on J3 during the light-emitting phase, so that the driving voltage VCC is provided to the light-emitting module L through the driving switch M1, thereby causing the light-emitting module L to emit light. The driving switch M1 adjusts the brightness of the light-emitting module L based on the driving voltage VCC received at its first connection terminal and the second voltage V2 received at its control terminal.

[0057] In this embodiment, the driving voltage VCC is high, and the driving switch M1 is a low-level conducting transistor, such as a PMOS transistor. The first connection terminal, the second connection terminal, and the control terminal of the driving switch M1 correspond one-to-one with the source, drain, and gate of the PMOS transistor. The light-emitting module L is an OLED, and the first and second terminals of the light-emitting module L correspond one-to-one with the cathode and anode of the OLED. In other embodiments, the light-emitting module can also be an LED (Light-Emitting Diode), a MicroLED (Micro Light-Emitting Diode), or a MiniLED (Mini Light-Emitting Diode). The energy storage module C is an energy storage capacitor.

[0058] It should be noted that during the reset phase J1, since the reset circuit H1 grounds the first terminal G of the energy storage module C and resets the voltage of the second terminal N of the energy storage module C to the driving voltage VCC, at this time, the voltage VG1 of the first terminal G of the energy storage module C is 0, the voltage VN1 of the second terminal N is VCC, and the voltage ΔV1 between the first terminal G and the second terminal N is VG1-VN1=0-VCC=-VCC.

[0059] At the beginning of the threshold compensation phase J2, the first terminal G of the energy storage module C is disconnected from ground, while the second terminal N of the energy storage module C is grounded, i.e., the voltage VN2 of the second terminal N is 0. Since the energy storage module C has a voltage holding characteristic (i.e., the voltage across the capacitor cannot change abruptly), the potential of the first terminal G changes to a third voltage V3, where the third voltage V3 is the difference between the ground potential and the driving voltage VCC.

[0060] VG20 = V3 = VN2 + ΔV1 = -VCC, thus the driving switch M1 is turned on. In the threshold compensation stage J2, the turned-on threshold compensation circuit H2 is connected to the driving voltage VCC through the first terminal of the driving switch M1 and provided to the first terminal G of the energy storage module C, so that the potential of the first terminal G of the energy storage module C continuously rises until the first voltage V1. At this time, the source-gate voltage Vsg of the driving switch M1 = VCC - V1 = Vth, thus just entering the near-cutoff state. Therefore, the potential of the first terminal G of the energy storage module C no longer changes and remains at V1, that is, VG2 = V1 = VCC - Vth. The voltage ΔV2 between the first terminal G and the second terminal N of the energy storage module C is VG2 - VN2 = VCC - Vth.

[0061] During the light-emitting stage J3, the data writing circuit H4 is turned on, adjusting the potential of the second terminal N of the energy storage module C to the data voltage Vdata, i.e., VN3 = Vdata. Since the energy storage module C has voltage holding characteristics, the potential of the first terminal G changes to the second voltage V2, i.e.:

[0062] VG3=V2=VN3+ΔV2=Vdata+VCC-Vth.

[0063] When the light-emitting circuit H3 is turned on, the driving switch M1 adjusts the brightness of the light-emitting module L based on the driving voltage VCC received at its first connection terminal and the second voltage V2 received at its control terminal. Specifically, the driving switch M1 adjusts the driving current Ids flowing through the light-emitting module L according to the magnitude of its source-gate voltage Vsg, thereby adjusting the brightness of the light-emitting module L. Specifically, based on the transistor's operating characteristics, the driving current Ids and the source-gate voltage Vsg have the following relationship:

[0064] Ids=(K / 2)(Vsg-Vth) 2 =(K / 2)[VCC-(Vdata+VCC-Vth)-Vth] 2 = (K / 2)(-Vdata) 2 .

[0065] Where K = Cox × μ × W / L, Cox is the gate capacitance per unit area; μ is the channel electron mobility; and W / L is the width-to-length ratio of the channel of the driving switch M.

[0066] As can be seen from the above formula, the threshold compensation circuit H2 can compensate the voltage of the control terminal of the driving switch M1 to the first voltage V1 during the threshold compensation stage J2, and the data writing circuit H4 provides the data voltage Vdata to the second terminal N of the energy storage module C during the light emission stage J3. This allows the energy storage module C to adjust the potential of the control terminal of the driving switch M1 to the second voltage V2 based on the voltage holding characteristic. Consequently, the driving current Ids flowing through the light emission module L is independent of the threshold voltage Vth of the driving switch M1. Therefore, the problem of uneven display brightness caused by the different threshold voltages Vth of the driving switch M1 in different pixel circuits 100 can be solved.

[0067] The pixel circuit 100 provided in this application adjusts the potential of the first terminal G of the energy storage module C to the first voltage V1 through the threshold compensation circuit H2 during the threshold compensation stage J2, and provides the data voltage Vdata to the second terminal N of the energy storage module C through the data writing circuit H4 during the light emission stage J3. This allows the energy storage module C to adjust the potential of the control terminal of the driving switch M1 to the second voltage V2 based on the voltage holding characteristic. Consequently, the driving switch M1 adjusts the light emission brightness of the light emission module L based on the driving voltage VCC received at its first connection terminal and the second voltage V2 received at its control terminal. This can compensate for the threshold voltage Vth of the driving switch M1, making the light emission brightness of the light emission module L independent of the threshold voltage Vth. This solves the problem of uneven display brightness caused by different threshold voltage Vth of the driving switch M1 in different pixel circuits 100.

[0068] For a more detailed description of the circuit structure and working principle of the pixel circuit 100 provided in this application, please refer to [the relevant documentation / reference needed]. Figures 3-6 .in, Figure 3 This is a timing diagram of the operation of the pixel circuit 100 during the display cycle of one frame. Figure 4 This is a circuit diagram of the pixel circuit 100 during the reset phase J1. Figure 5 This is a circuit diagram of the pixel circuit 100 in the threshold compensation stage J2. Figure 6 This is a circuit diagram of the pixel circuit 100 in the light-emitting stage J3.

[0069] like Figure 4As shown, the pixel circuit 100 further includes a first switch transistor T1 located in the reset circuit H1. The first switch transistor T1 includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the first switch transistor T1 is grounded, and the second connection terminal of the first switch transistor T1 is electrically connected to the first terminal G of the energy storage module C.

[0070] During the reset phase J1, the first switch T1 is turned on based on the first scan signal S1 received at its control terminal, so that the first terminal G of the energy storage module C is grounded through the turned-on first switch T1.

[0071] Furthermore, the pixel circuit 100 also includes a second switch T2 located in the reset circuit H1. The second switch T2 includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the second switch T2 is used to receive the driving voltage VCC, and the second connection terminal of the second switch T2 is electrically connected to the second terminal N of the energy storage module C.

[0072] The second switch T2, the energy storage module C, and the first switch T1 are connected in series to form the reset circuit H1. During the reset phase J1, the first switch T1 is turned on based on the first scan signal S1 received at its control terminal, and the second switch T2 is turned on based on the second scan signal S2 received at its control terminal, thereby turning on the reset circuit H1.

[0073] like Figure 5 As shown, the pixel circuit 100 also includes a third switch T3 located in the threshold compensation circuit H2. The third switch T3 includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the third switch T3 is grounded, and the second connection terminal of the third switch T3 is electrically connected to the second terminal N of the energy storage module C.

[0074] During the threshold compensation stage J2, the third switch T3 is turned on based on the third scan signal S3 received at its control terminal, so that the second terminal N of the energy storage module C is grounded through the turned-on third switch T3, thereby causing the energy storage module C to adjust the potential of the control terminal of the drive switch M1 to the third voltage V3 based on the voltage holding characteristic, and thus turn on the drive switch M1.

[0075] Furthermore, the pixel circuit 100 also includes a fourth switch T4 located in the threshold compensation circuit H2. Each fourth switch T4 includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the fourth switch T4 is electrically connected to the second connection terminal of the driving switch M1, and the second connection terminal of the fourth switch T4 is electrically connected to the first terminal G of the energy storage module C.

[0076] The driving switch M1, the fourth switch T4, the energy storage module C, and the third switch T3 are connected in series to form the threshold compensation circuit H2. During the threshold compensation stage J2, the third switch T3 is turned on based on the third scan signal S3 received at its control terminal, the driving switch M1 is turned on based on the third voltage V3 received at its control terminal, and the fourth switch T4 is turned on based on the fourth scan signal S4 received at its control terminal, thereby activating the threshold compensation circuit H2.

[0077] like Figure 6 As shown, the pixel circuit 100 also includes a data writing switch M2 located in the data writing circuit H4. The data writing switch M2 includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the data writing switch M2 is used to receive the data voltage Vdata, and the second connection terminal of the data writing switch M2 is electrically connected to the second terminal N of the energy storage module C.

[0078] During the light-emitting stage J3, the data writing switch M2 is turned on based on the data writing control signal received at its control terminal, thereby enabling the second terminal N of the energy storage module C to receive the data voltage Vdata through the turned-on data writing switch M2.

[0079] Furthermore, the pixel circuit 100 also includes a voltage follower U1, which has an input terminal and an output terminal. The input terminal of the voltage follower U1 is electrically connected to the second connection terminal of the data writing switch M2, and the output terminal of the voltage follower U1 is electrically connected to the second terminal N of the energy storage module C.

[0080] The data writing switch M2 and the voltage follower U1 are connected in series to form the data writing circuit H4. The data writing circuit H4 is used to turn on J3 during the light emission stage, connect the data voltage Vdata and provide it to the second terminal N of the energy storage module C.

[0081] It should be noted that the voltage follower U1 is set between the data writing switch M2 and the second terminal N of the energy storage module C. On the one hand, it can improve the signal driving force of the data writing circuit H4, that is, reduce the loss of data voltage Vdata during transmission, thereby effectively ensuring the accuracy of the data voltage Vdata received by the pixel circuit 100, and thus realizing precise control of the light emission brightness of the light-emitting module L. On the other hand, the voltage follower U1 can play the role of impedance transformation, so that the subsequent pixel circuit 100 and the previous data voltage transmission circuit do not affect each other.

[0082] Furthermore, the pixel circuit 100 also includes a fifth switch transistor T5 located in the light-emitting circuit H3. The fifth switch transistor T5 includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the fifth switch transistor T5 is electrically connected to the second connection terminal of the driving switch transistor M1, and the second connection terminal of the fifth switch transistor T5 is electrically connected to the second terminal of the light-emitting module L.

[0083] The driving switch M1, the fifth switch T5, and the light-emitting module L are connected in series to form the light-emitting circuit. During the light-emitting stage J3, the driving switch M1 is turned on based on the second voltage V2 received at its control terminal, and the fifth switch T5 is turned on based on the fifth scan signal S5 received at its control terminal, thereby turning on the light-emitting circuit H3.

[0084] Furthermore, the pixel circuit 100 also includes a data write control circuit 10 for generating the data write control signal, the data write control circuit 10 including a sixth switch T6, a comparator U2 and a D flip-flop U3.

[0085] The sixth switch T6 includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the sixth switch T6 is electrically connected to the first terminal G of the energy storage module C.

[0086] The comparator U2 includes a non-inverting input terminal, an inverting input terminal, and an output terminal. The non-inverting input terminal of the comparator U2 is electrically connected to the second terminal of the sixth switching transistor T6, and the inverting output terminal of the comparator U2 is grounded. The comparator U2 is used to output a corresponding comparison signal based on the relationship between the voltage at the non-inverting input terminal and the voltage at the inverting input terminal.

[0087] The D flip-flop U3 includes a D input terminal, a clock signal input terminal, and a Q output terminal. The D input terminal of the D flip-flop U3 is used to receive a trigger voltage VCR with a constant voltage value. The clock signal input terminal of the D flip-flop U3 is electrically connected to the output terminal of the comparator U2 and is used to receive the comparison signal output by the output terminal of the comparator U2. The Q output terminal of the D flip-flop U3 is electrically connected to the data writing switch M2. The D flip-flop U3 outputs the trigger voltage VCR through the Q output terminal in response to the level transition of the comparison signal.

[0088] During the light-emitting stage J3, the sixth switch T6 is turned on based on the sixth scan signal S6 received at its control terminal, causing the comparator U2 to be electrically connected to the first terminal G of the energy storage module C through the turned-on sixth switch T6. This causes the comparison signal output by the comparator U2 to jump from a low level to a high level, thereby causing the D flip-flop U3 to output the trigger voltage VCR through its Q output terminal in response to the comparison signal jumping from a low level to a high level. The data write control signal output by the data write control circuit 10 is the trigger voltage VCR output by the Q output terminal of the D flip-flop U3.

[0089] It should be noted that, since the comparator U2 outputs a high-level signal when the voltage at the non-inverting input is higher than the voltage at the inverting input, and a low-level signal when the voltage at the inverting input is higher than the voltage at the non-inverting input, the sixth switch T6 is turned off before the light-emitting stage J3, resulting in a low-level comparator signal output by the comparator U2. At the beginning of the light-emitting stage J3, the potential of the first terminal G of the energy storage module C is the first voltage V1>0, causing the comparator signal output by the comparator U2 to jump from low to high. This causes the D flip-flop U3 to output the trigger voltage VCR through the Q output terminal, thereby turning on the data writing switch M2 and providing the data voltage Vdata to the second terminal N of the energy storage module C.

[0090] It is easy to understand that, due to the resistance and parasitic capacitance of the scan lines in the display panel, there is an RC delay in the transmission of the scan signal. Therefore, the scan signal received by the switching transistor in the pixel circuit 100 is not actually an ideal square wave signal. As a result, the switching transistor does not turn on completely instantly when it receives the scan signal, but gradually turns on. Therefore, if the sixth scan signal S6 is directly used as the data writing control signal, the turning-on speed of the data writing switching transistor M2 will be relatively slow, thus affecting the light-emitting effect of the light-emitting module L. In this embodiment, by configuring the data writing control circuit 10, the sixth switch T6, in response to the sixth scan signal S6 at a very small degree of on-state, can cause the comparison signal output by the comparator U2 to jump from a low level to a high level. This causes the D flip-flop U3 to output the trigger voltage VCR to the data writing switch M2. Since the voltage value of the trigger voltage VCR is constant, the data writing switch M2 can be fully turned on the instant it receives the trigger voltage VCR, providing the data voltage Vdata to the second terminal N of the energy storage module C. This eliminates the influence of the RC delay of the scan signal on the writing speed of the data voltage Vdata, thereby improving the display effect of the light-emitting module L.

[0091] It should be noted that in other embodiments, the first connection terminal of the sixth switch T6 may also be electrically connected to other components with a high potential instead of being electrically connected to the first terminal G of the energy storage module C. For example, the first connection terminal of the sixth switch T6 may directly receive the driving voltage VCC.

[0092] In this embodiment, the first switch T1 to the sixth switch T6 and the data write switch M2 are all high-level conducting transistors. Each switch in this embodiment can be an amorphous silicon thin-film transistor (a-Si TFT), a low-temperature polycrystalline silicon thin-film transistor (LTPS TFT), or an oxide semiconductor thin-film transistor (Oxide TFT). The active layer of the oxide semiconductor thin-film transistor is made of oxide semiconductor, such as indium gallium zinc oxide (IGZO). Of course, in other embodiments, the first switch T1 to the sixth switch T6 and the data write switch M2 can also be low-level conducting transistors; this is not a limitation.

[0093] The following is combined Figures 3-6 The following is a detailed description of the workflow of the pixel circuit 100 provided in this application within the display cycle of one frame:

[0094] In this embodiment, a separate scanning signal is provided for each switching transistor to control it. In other embodiments, switching transistors with the same turn-on timing can share a single scanning signal, thus simplifying the wiring structure. For example, the first switching transistor T1 and the second switching transistor T2 can share the first scanning signal S1, the third switching transistor T3 and the fourth switching transistor T4 can share the third scanning signal S3, and the fifth switching transistor T5 and the sixth switching transistor T6 can share the fifth scanning signal S5.

[0095] During the reset phase J1, the first scan signal S1 and the second scan signal S2 are both high, while the other scan signals are low. Therefore, the first switch T1 and the second switch T2 are both turned on, while the third switch T3, the fourth switch T4, the fifth switch T5, the sixth switch T6, and the data write switch M2 are all turned off. This causes the reset circuit H1 to conduct, resetting the voltage at the second terminal N of the energy storage module C to the driving voltage VCC, and grounding the first terminal G. At this time, since the control terminal of the driving switch M1 is at ground potential, the driving switch M1 is turned on.

[0096] During the threshold compensation stage J2, the third scan signal S3 and the fourth scan signal S4 are both at high level, while other scan signals are at low level. Therefore, the third switch T3 and the fourth switch T4 are both turned on, while the first switch T1, the second switch T2, the fifth switch T5, the sixth switch T6, and the data write switch M2 are all turned off. This causes the threshold compensation circuit H2 to be turned on, providing the driving voltage VCC to the first terminal G of the energy storage module C, thereby causing the potential of the first terminal G of the energy storage module C to change to the first voltage V1.

[0097] During the light-emitting stage J3, the fifth scan signal S5 and the sixth scan signal S6 are both at high levels, while the other scan signals are at low levels. Therefore, the fifth switch T5, the sixth switch T6, the drive switch M1, and the data writing switch M2 are all turned on, while the first switch T1, the second switch T2, the third switch T3, and the fourth switch T4 are all turned off. This causes the data writing circuit H4 to turn on, providing the data voltage Vdata to the second terminal N of the energy storage module C. Consequently, the energy storage module C, based on its voltage holding characteristics, adjusts the potential of the control terminal of the drive switch M1 to the second voltage V2, and causes the light-emitting circuit H3 to turn on, providing the drive voltage VCC to the light-emitting module L. This causes the light-emitting module L to emit light. At this time, the drive switch M1 adjusts the brightness of the light-emitting module L based on the drive voltage VCC received at its first connection terminal and the second voltage V2 received at its control terminal.

[0098] Please see Figure 7 This application also provides a display panel 1, which includes a scan driver 110, a data driver 120, and a plurality of pixel circuits 100 as described in any of the above embodiments.

[0099] The data driver 120 is used to generate a data voltage Vdata and output it to the pixel circuit 100.

[0100] The scan driver 110 is used to generate a number of scan signals and output them to the pixel circuit 100 to drive the pixel circuit 100 to work sequentially in the reset stage J1, threshold compensation stage J2 and light emission stage J3 in the display cycle of a frame.

[0101] Furthermore, the display panel 1 includes a substrate 1000, which includes a display area 1001 and a non-display area 1002. A plurality of pixel circuits 100 are arrayed within the display area 1001.

[0102] The display panel 1 further includes a plurality of scan lines 111 extending along the row direction and all electrically connected to the scan driver 110, and a plurality of data lines 121 extending along the column direction and all electrically connected to the data driver 120. Pixel circuits 100 located in the same column are electrically connected to a corresponding data line 121, and pixel circuits 100 located in the same row are electrically connected to multiple corresponding scan lines 111. The number of scan lines 111 electrically connected to each row of pixel circuits 100 corresponds to the number of scan signals received by the pixel circuit 100.

[0103] The data driver 120 outputs the data voltage Vdata to each column of the pixel circuit 100 through the plurality of data lines 121, and the scan driver 110 outputs the plurality of scan signals to each row of the pixel circuit 100 through the plurality of scan lines 111.

[0104] The pixel circuit 100 in the display panel 1 provided in this application adjusts the potential of the first terminal G of the energy storage module C to the first voltage V1 through the threshold compensation circuit H2 during the threshold compensation stage J2, and provides the data voltage Vdata to the second terminal N of the energy storage module C through the data writing circuit H4 during the light emission stage J3. This allows the energy storage module C to adjust the potential of the control terminal of the driving switch transistor M1 to the second voltage V2 based on the voltage holding characteristic. Consequently, the driving switch transistor M adjusts the light emission brightness of the light emission module L based on the driving voltage VCC received at its first connection terminal and the second voltage V2 received at its control terminal. This can compensate for the threshold voltage Vth of the driving switch transistor M1, making the light emission brightness of the light emission module L independent of the threshold voltage Vth. This solves the problem of uneven display brightness caused by different threshold voltages Vth of the driving switch transistors M in different pixel circuits 100.

[0105] It will be apparent to those skilled in the art that this application is not limited to the details of the exemplary embodiments described above, and that this application can be implemented in other specific forms without departing from the spirit or essential characteristics of this application. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this application is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be embraced within this application. No reference numerals in the claims should be construed as limiting the scope of the claims. Furthermore, it is clear that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units or devices recited in the apparatus claims may also be implemented by the same unit or device in software or hardware.

[0106] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A pixel circuit, characterized in that, The pixel circuit operates sequentially in a reset phase, a threshold compensation phase, and a light emission phase during the display cycle of one frame. The pixel circuit includes: A light-emitting module includes a first terminal and a second terminal, wherein the first terminal of the light-emitting module is grounded; The driving switch includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal is used to receive the driving voltage, and the second connection terminal is electrically connected to the second terminal of the light-emitting module. An energy storage module includes a first end and a second end, wherein the first end of the energy storage module is electrically connected to the control end of the drive switch transistor. A reset circuit, wherein the energy storage module is located in the reset circuit, the reset circuit is used to turn on during the reset phase, ground the first terminal of the energy storage module, and provide the driving voltage to the second terminal of the energy storage module, so as to reset the voltage of the second terminal of the energy storage module to the driving voltage; A threshold compensation circuit is provided, wherein the driving switch and the energy storage module are connected in series in the threshold compensation circuit. The threshold compensation circuit is used to turn on during the threshold compensation stage, disconnect the electrical connection between the first terminal of the energy storage module and ground, and ground the second terminal of the energy storage module, so that the driving voltage is provided to the first terminal of the energy storage module through the driving switch, thereby causing the potential of the first terminal of the energy storage module to change to a first voltage, wherein the first voltage is the difference between the driving voltage and the threshold voltage of the driving switch. A data writing circuit is electrically connected to the second terminal of the energy storage module. This data writing circuit is used to turn on during the light-emitting phase, providing a data voltage to the second terminal of the energy storage module. This allows the energy storage module to adjust the potential of the control terminal of the driving switch to a second voltage based on its voltage holding characteristics. The second voltage is the sum of the first voltage and the data voltage. A light-emitting circuit, wherein the driving switch and the light-emitting module are connected in series in the light-emitting circuit, the light-emitting circuit is used to be turned on during the light-emitting stage, so that the driving voltage is provided to the light-emitting module through the driving switch, thereby causing the light-emitting module to emit light; wherein the driving switch adjusts the light-emitting brightness of the light-emitting module based on the driving voltage received at its first connection terminal and the second voltage received at its control terminal.

2. The pixel circuit as described in claim 1, characterized in that, The pixel circuit also includes a first switching transistor located in the reset circuit. The first switching transistor includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the first switching transistor is grounded, and the second connection terminal of the first switching transistor is electrically connected to the first terminal of the energy storage module. During the reset phase, the first switch is turned on based on a first scan signal received at its control terminal, so that the first terminal of the energy storage module is grounded through the turned-on first switch.

3. The pixel circuit as described in claim 2, characterized in that, The pixel circuit also includes a second switching transistor located in the reset circuit. The second switching transistor includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the second switching transistor is used to receive the driving voltage, and the second connection terminal of the second switching transistor is electrically connected to the second terminal of the energy storage module. During the reset phase, the first switch is turned on based on a first scan signal received at its control terminal, and the second switch is turned on based on a second scan signal received at its control terminal, thereby turning on the reset circuit.

4. The pixel circuit as described in claim 1, characterized in that, The driving voltage is high level, and the driving switch is a low level switch. The pixel circuit also includes a third switch located in the threshold compensation circuit. The third switch includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the third switch is grounded, and the second connection terminal of the third switch is electrically connected to the second terminal of the energy storage module. During the threshold compensation phase, the third switch is turned on based on the third scan signal received at its control terminal, so that the second terminal of the energy storage module is grounded through the turned-on third switch, thereby causing the energy storage module to adjust the potential of the control terminal of the drive switch to the third voltage based on the voltage holding characteristic, and thus turn on the drive switch; wherein, the third voltage is the difference between the ground potential and the drive voltage.

5. The pixel circuit as described in claim 4, characterized in that, The pixel circuit also includes a fourth switch located in the threshold compensation circuit. Each fourth switch includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the fourth switch is electrically connected to the second connection terminal of the driving switch, and the second connection terminal of the fourth switch is electrically connected to the first terminal of the energy storage module. During the threshold compensation phase, the third switch is turned on based on the third scan signal received at its control terminal, the drive switch is turned on based on the third voltage received at its control terminal, and the fourth switch is turned on based on the fourth scan signal received at its control terminal, thereby activating the threshold compensation circuit.

6. The pixel circuit as described in claim 1, characterized in that, The pixel circuit also includes a fifth switching transistor located in the light-emitting circuit. The fifth switching transistor includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the fifth switching transistor is electrically connected to the second connection terminal of the driving switching transistor, and the second connection terminal of the fifth switching transistor is electrically connected to the second terminal of the light-emitting module. During the light-emitting phase, the driving switch is turned on based on the second voltage received at its control terminal, and the fifth switch is turned on based on the fifth scan signal received at its control terminal, thereby turning on the light-emitting circuit.

7. The pixel circuit as described in claim 1, characterized in that, The pixel circuit also includes a data writing switch located in the data writing loop. The data writing switch includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the data writing switch is used to receive data voltage, and the second connection terminal of the data writing switch is electrically connected to the second terminal of the energy storage module. During the light-emitting phase, the data writing switch is turned on based on the data writing control signal received at its control terminal, thereby enabling the second terminal of the energy storage module to receive the data voltage through the turned-on data writing switch.

8. The pixel circuit as described in claim 7, characterized in that, The pixel circuit also includes a voltage follower located in the data writing loop. The voltage follower includes an input terminal and an output terminal. The input terminal of the voltage follower is electrically connected to the second connection terminal of the data writing switch transistor, and the output terminal of the voltage follower is electrically connected to the second terminal of the energy storage module.

9. The pixel circuit as described in claim 7, characterized in that, The pixel circuit further includes a data write control circuit for generating the data write control signal, the data write control circuit comprising: The sixth switching transistor includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal of the sixth switching transistor is electrically connected to the first terminal of the energy storage module. A comparator includes a non-inverting input, an inverting input, and an output. The non-inverting input is electrically connected to the second terminal of the sixth switching transistor, and the inverting output is grounded. The comparator outputs a comparison signal based on the relationship between the voltages at the non-inverting and inverting inputs. A D flip-flop includes a D input, a clock signal input, and a Q output. The D input receives a constant trigger voltage. The clock signal input is electrically connected to the output of a comparator and receives the comparison signal output by the comparator. The Q output is electrically connected to a data write switch. The D flip-flop outputs the trigger voltage through its Q output in response to a level change in the comparison signal. During the light-emitting phase, the sixth switch is turned on based on the sixth scan signal received at its control terminal, causing the comparator to be electrically connected to the first terminal of the energy storage module through the turned-on sixth switch. This causes the comparison signal output by the comparator to jump from a low level to a high level, thereby causing the D flip-flop to output the trigger voltage through the Q output terminal in response to the comparison signal jumping from a low level to a high level. The data write control signal output by the data write control circuit is the trigger voltage output by the Q output terminal of the D flip-flop.

10. A display panel, characterized in that, include: The pixel circuit as described in any one of claims 1 to 9; A data driver is used to generate data voltage and output it to the pixel circuit. as well as A scan driver is used to generate several scan signals and output them to the pixel circuit to drive the pixel circuit to work sequentially in the reset phase, threshold compensation phase and light emission phase during the display cycle of one frame.

Images