Display driving circuit, self-luminous display panel and display device

Abstract

The present application discloses a display driving circuit, a self-luminous display panel and a display device, wherein the display driving circuit comprises: a first thin film transistor, a controlled end for receiving a scanning signal, and an input end for receiving a data signal; a second thin film transistor, a controlled end connected to the output end of the first thin film transistor; a signal conversion circuit, an input end for receiving a scanning signal, and a signal conversion circuit for converting the scanning signal into a light-emitting control signal and outputting it; a light-emitting control circuit, a controlled end connected to the output end of the signal conversion circuit, a first input end for receiving a power supply voltage, a second input end connected to the output end of the second thin film transistor, a first output end connected to the input end of the second thin film transistor, and an output end connected to a self-luminous device; and a light-emitting control circuit for outputting the power supply voltage through the second thin film transistor when receiving a light-emitting control signal of a first preset potential. The technical solution of the present application can reduce the influence of dead time on the self-luminous device.

Description

Technical Field

[0001] The present application relates to the field of display driving technology, and in particular to a display driving circuit, a self-luminous display panel and a display device. Background Art

[0002] At present, self-luminous panels are widely used because they use self-luminous devices such as OLED as pixels, which can achieve better display effects than liquid crystal panels. However, in actual settings, the existing display driving circuits used to drive the self-luminous devices to emit light will use more thin-film transistors, and there is a dead time when the thin-film transistors are turned on in turn, which affects the light emission of the self-luminous devices. Summary of the invention

[0003] The main purpose of the present application is to provide a display driving circuit, aiming to solve the problem that the dead time affects the light emission of a self-luminous device.

[0004] To achieve the above-mentioned object, the display driving circuit proposed in the present application is applied to a self-luminous display panel, wherein the self-luminous display panel includes a self-luminous device, and is characterized in that the display driving circuit includes:

[0005] A first thin film transistor, a controlled end for receiving a scan signal, and an input end for receiving a data signal;

[0006] a second thin film transistor, a controlled end of which is connected to the output end of the first thin film transistor;

[0007] A signal conversion circuit, the input end of which is used to receive a scanning signal, and the signal conversion circuit is used to convert the scanning signal into a light-emitting control signal and then output it; and

[0008] A light emitting control circuit, wherein a controlled end is connected to the output end of the signal conversion circuit, a first input end is used to access a power supply voltage, a second input end is connected to the output end of the second thin film transistor, a first output end is connected to the input end of the second thin film transistor, and an output end is connected to the self-luminous device;

[0009] The light emitting control circuit is used for outputting the power supply voltage to the self-luminous device via the second thin film transistor when receiving a light emitting control signal of a first preset potential.

[0010] Optionally, the light emitting control circuit further includes:

[0011] a third thin film transistor, a controlled end connected to the output end of the signal conversion circuit, an input end for connecting to a power supply voltage, and an output end connected to the input end of the second thin film transistor;

[0012] A fourth thin film transistor has a controlled end connected to the output end of the signal conversion circuit, an input end connected to the output end of the second thin film transistor, and an output end connected to the self-luminous device.

[0013] Optionally, the light emitting control circuit further includes:

[0014] The fifth thin film transistor has a controlled end connected to the output end of the signal conversion circuit, an input end for receiving a light-emitting driving signal, and an output end connected to the controlled ends of the third thin film transistor and the fourth thin film transistor respectively.

[0015] Optionally, the target signal has a high potential stage and a low potential stage that are entered alternately; wherein the high potential stage includes at least one overcharge sub-stage, and the potential value of the target signal in any overcharge sub-stage is greater than a preset high potential value corresponding to the target signal in the high potential stage;

[0016] Wherein, the target signal is the data signal and / or the light-emitting driving signal.

[0017] Optionally, the potential value of the target signal in each of the overcharging sub-stages decreases in sequence with the order in which each of the overcharging sub-stages is entered.

[0018] Optionally, when the target signal enters the high potential stage, it enters an overcharge sub-stage with the maximum potential.

[0019] Optionally, the overcharge sub-stages in a high potential stage are distributed continuously.

[0020] Optionally, the scanning signal has an opposite potential to that of the light emitting control signal.

[0021] The present invention further provides a self-luminous display panel, the self-luminous display panel comprising:

[0022] Self-luminous device; and

[0023] As the display driving circuit mentioned above, the display driving circuit is connected to the self-luminous device.

[0024] The present invention further provides a display device, which includes the self-luminous display panel as described above.

[0025] The technical solution of the present application generates a light-emitting control signal by inverting the potential of a scanning signal so that the potentials of the scanning signal and the light-emitting control signal are opposite, thereby avoiding the first thin-film transistor, the second thin-film transistor and the corresponding thin-film transistor in the light-emitting control circuit being in the on state at the same time during the dead time, which affects the charging effect of the storage capacitor, thereby solving the problem of the dead time affecting the light-emitting effect of the self-luminous device, which is beneficial to improving the display effect of the self-luminous display panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0027] Figure 1 This is a circuit diagram of a display driving circuit according to Embodiment 1 of the present application;

[0028] Figure 2 This is a schematic diagram showing the target signal waveform and the corresponding charging effect in the driving circuit according to the first embodiment of the present application.

[0029] Description of Figure Numbers:

[0030]

[0031] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0033] In addition, in this application, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0034] Embodiment 1

[0035] The present application provides a display driving circuit which can be applied to a self-luminous display panel.

[0036] The self-luminous display panel may include a plurality of self-luminous devices arranged in an array and a plurality of pixel driving circuits; each pixel driving circuit is arranged corresponding to a self-luminous device to drive the corresponding self-luminous device to emit light; wherein the self-luminous device can be implemented by an organic light-emitting device such as OLED, which will not be elaborated here.

[0037] Reference Figure 1 , the display driving circuit includes:

[0038] The first thin film transistor T1 has a controlled end for receiving a scan signal Scan and an input end for receiving a data signal Data;

[0039] A second thin film transistor T2, a controlled end of which is connected to the output end of the first thin film transistor T1;

[0040] The signal conversion circuit 10 has an input end for receiving a scanning signal Scan, and the signal conversion circuit 10 is used to convert the scanning signal Scan into a light emitting control signal and then output it;

[0041] The light emitting control circuit 20 has a controlled end connected to the output end of the signal conversion circuit 10, a first input end for accessing the power supply voltage VDD, a second input end connected to the output end of the second thin film transistor T2, a first output end connected to the input end of the second thin film transistor T2, and an output end connected to the self-luminous device OLED;

[0042] The light emitting control circuit 20 is used for outputting the power supply voltage VDD to the self-luminous device OLED via the second thin film transistor T2 when receiving the light emitting control signal of the first preset potential.

[0043] In this embodiment, the controlled end of the first thin film transistor T1 can be connected to the gate driving circuit to access the scanning signal Scan output by the gate driving circuit; the scanning signal Scan can have a first preset potential and a second preset potential, one of which can be a high potential and the other can be a low potential; wherein the first preset potential is used to trigger the first thin film transistor T1 to turn on, and the second preset potential is used to trigger the first thin film transistor T1 to turn off. This embodiment is explained by assuming that the first thin film transistor T1 and the second thin film transistor T2 are N-type thin film transistors, the first preset potential is a high potential, and the second preset potential is a low potential.

[0044] The cathode of the self-luminous device OLED can be connected to the ground voltage VSS, and a first storage capacitor Cst can be connected between the cathode of the self-luminous device OLED and the controlled end of the second thin film transistor T2. The gate driving circuit can determine that when the self-luminous device OLED is driven to work at the level where it is located, it outputs a scan signal Scan of a first preset potential to the first thin film transistor T1 to trigger the first thin film transistor T1 to turn on, so that the turned-on first thin film transistor T1 can be connected to the data voltage Data output by the source driving circuit and output to the first storage capacitor Cst, so as to pre-charge the first storage capacitor Cst, and after the pre-charging of the first storage capacitor Cst is completed, the terminal voltage of the first storage capacitor Cst can be used to trigger the second thin film transistor T2 to turn on.

[0045] The light emitting control circuit 20 can be implemented by a switch circuit constructed by thin film transistors. The light emitting control signal can also have a first preset potential and a second preset potential, wherein the first preset potential is used to trigger the corresponding thin film transistors in the light emitting control circuit 20 to turn on, so that each thin film transistor that is turned on can output the power supply voltage VDD to the second thin film transistor T2, and each thin film transistor that is turned on can be connected to the output power supply voltage VDD of the second thin film transistor T2 that is turned on and output to the anode of the self-luminous device OLED, thereby driving the self-luminous device OLED to emit light.

[0046] However, it is found in the actual setting that in order to avoid the first thin film transistor T1, the second thin film transistor T2 and the corresponding thin film transistors in the light emitting control circuit 20 being in the on state at the same time, when the scanning signal Scan is in the first preset potential, the light emitting control signal needs to be in the second preset potential; and when the light emitting control signal is switched from the second preset potential to the first preset potential, the scanning signal Scan needs to be switched from the first preset potential to the second preset potential. However, in the switching process of the above preset potentials, the scanning signal Scan and the light emitting control signal have a signal edge duration, specifically: the scanning signal Scan has a falling edge duration in the process of switching from the first preset potential to the second preset potential, and the light emitting control signal has a rising edge duration in the process of switching from the second preset potential to the first preset potential. However, due to the differences in various factors such as the output circuits of the light-emitting control signal and the scanning signal Scan and the transmission path impedance, the light-emitting control signal and the scanning signal Scan are likely to be in a higher potential state at the same time for a period of time during the switching process, and this period of time is the dead time. During this period of time, the first thin-film transistor T1, the second thin-film transistor T2 and the corresponding thin-film transistors in the light-emitting control circuit 20 are in the on state at the same time, which affects the charging effect of the storage capacitor Cst, and further affects the light-emitting effect of the self-luminous device OLED.

[0047] The signal conversion circuit 10 can be implemented by using a rising edge trigger or a falling edge trigger; for example: Figure 1 In the illustrated embodiment, the first thin film transistor T1 is an N-type thin film transistor, and the signal conversion circuit 10 can be implemented by a falling edge trigger. The signal conversion circuit 10 can perform a potential inversion process on the scan signal Scan when the potential value of the connected scan signal Scan rises to a preset high potential threshold, or drops to a preset low potential threshold, and can output the scan signal Scan after the potential inversion as a light-emitting control signal. In other words, the potential of the scan signal Scan in the present application is opposite to that of the light-emitting control signal.

[0048] In this way, the technical solution of the present application generates a light-emitting control signal by inverting the potential of the scanning signal Scan, so that the potentials of the scanning signal and the light-emitting control signal are opposite, thereby avoiding the first thin-film transistor T1, the second thin-film transistor T2 and the corresponding thin-film transistors in the light-emitting control circuit 20 being in the on state at the same time during the dead time, which affects the charging effect of the storage capacitor Cst, thereby solving the problem that the dead time affects the light-emitting effect of the self-luminous device OLED, which is beneficial to improving the display effect of the self-luminous display panel.

[0049] Reference Figure 1 , the light emitting control circuit 20 further includes:

[0050] The third thin film transistor T3 has a controlled end connected to the output end of the signal conversion circuit 10, an input end for receiving the power supply voltage VDD, and an output end connected to the input end of the second thin film transistor T2;

[0051] The fourth thin film transistor T4 has a controlled end connected to the output end of the signal conversion circuit 10 , an input end connected to the output end of the second thin film transistor T2 , and an output end connected to the self-luminous device OLED.

[0052] The light emitting control circuit 20 may include a third thin film transistor T3 and a fourth thin film transistor T4. The controlled ends of the third thin film transistor T3 and the fourth thin film transistor T4 may be connected to the output end of the signal conversion circuit 10 to access the light emitting control signal. The input end of the third thin film transistor T3 may be connected to the power supply voltage VDD. The output end of the third thin film transistor T3 may be connected to the input end of the second thin film transistor T2. The input end of the fourth thin film transistor T4 may be connected to the output end of the second thin film transistor T2. The output end of the fourth thin film transistor T4 may be connected to the anode of the self-luminous device OLED.

[0053] The light emitting control signal of the first preset potential is used to trigger the third thin film transistor T3 and the fourth thin film transistor T4 to turn on, and the light emitting control signal of the second preset potential is used to trigger the third thin film transistor T3 and the fourth thin film transistor T4 to turn off. This embodiment is explained by assuming that the third thin film transistor T3 and the fourth thin film transistor T4 are both N-type thin film transistors. When the second thin film transistor T2 is turned on, the light emitting control signal can change from the second preset potential to the first preset potential to trigger the third thin film transistor T3 and the fourth thin film transistor T4 to turn on, so that the turned-on third thin film transistor T3 can output the power supply voltage VDD to the second thin film transistor T2, and the turned-on second thin film transistor T2 and the fourth thin film transistor T4 can output to the anode of the self-luminous device OLED, thereby driving the self-luminous device OLED to emit light.

[0054] However, in the actual setting, it is found that the luminous control signal generated and output by the signal conversion circuit 10 has a weak driving capability for the third thin-film transistor T3 and the fourth thin-film transistor T4, which makes it take a long time for the anode of the self-luminous device OLED to receive the power supply voltage VDD, which is not conducive to the high refresh rate design of the self-luminous panel.

[0055] To address this problem, in the technical solution of the present application, the light emitting control circuit 20 further includes:

[0056] The fifth thin film transistor T5 has a controlled end connected to the output end of the signal conversion circuit 10 , an input end for receiving the light emitting driving signal Emit, and an output end respectively connected to the controlled ends of the third thin film transistor T3 and the fourth thin film transistor T4 .

[0057] Among them, the signal amplitude of the light-emitting driving signal Emit can be greater than the signal amplitude of the light-emitting control signal, and thus can have a stronger driving capability than the light-emitting control signal. In this embodiment, the light-emitting control signal generated by the signal conversion circuit 10 is only used to drive the fifth thin-film transistor T5 to turn on, so that the turned-on fifth thin-film transistor T5 can be connected to the light-emitting driving signal Emit with a stronger driving capability, and output to the controlled end of the third thin-film transistor T3 and the fourth thin-film transistor T4, so as to realize the driving and turning on of the third thin-film transistor T3 and the fourth thin-film transistor T4. In this way, the light-emitting driving signal Emit with a stronger driving capability can be used to drive the third thin-film transistor T3 and the fourth thin-film transistor T4 to turn on, thereby shortening the time required for the anode of the self-luminous device OLED to receive the power supply voltage VDD, which is beneficial to the high refresh rate design of the self-luminous display panel.

[0058] However, it is also found in actual use that the third thin film transistor T3, the fourth thin film transistor T4, and the fifth thin film transistor T5 have relatively large parasitic capacitances, and the connected data signal Data and the light-emitting driving signal Emit will preferentially charge the parasitic capacitances when flowing into the thin film transistors, thus not only affecting the driving capability of the light-emitting driving signal Emit, but also affecting the stability of the power supply voltage VDD received by the self-luminous device OLED.

[0059] For this problem, refer to Figure 2 In the technical solution of the present application, the target signal has a high potential stage and a low potential stage that are entered alternately; wherein the high potential stage includes at least one overcharging sub-stage, and the potential value of the target signal in any overcharging sub-stage is greater than the preset high potential value V0 corresponding to the target signal in the high potential stage; wherein the target signal is a data signal Data and / or a light-emitting drive signal Emit.

[0060] Since the potential value of the target signal is greater than the preset high potential value V0 corresponding to the target signal in the high potential stage, the third thin film transistor T3 and the fourth thin film transistor T4 can use the data signal Data with a higher potential value to charge the parasitic capacitance at the third thin film transistor T3 and the fourth thin film transistor T4 when the connected data signal Data enters the overcharge sub-stage, and the fifth thin film transistor T5 can use the light-emitting driving signal Emit with a higher potential value to charge the parasitic capacitance at the fifth thin film transistor T5 when the connected light-emitting driving signal Emit enters the overcharge sub-stage. It can be understood that in the high potential stage, except for each overcharge sub-stage, the potential value of the target signal is equal to the preset high potential value V0 corresponding to the target signal in the high potential stage. In this way, compared with the potential value of the target signal maintaining the corresponding preset high potential value V0 in the high potential stage, the parasitic capacitance at the third thin film transistor T3, the fourth thin film transistor T4, and the fifth thin film transistor T5 can be quickly charged, thereby reducing the influence of the parasitic capacitance on the driving capability of the light-emitting driving signal Emit and the stability of the power supply voltage VDD, which is beneficial to improving the light-emitting effect of the self-luminous device OLED.

[0061] Optionally, the number of overcharging sub-stages can be set to one or two, so as to reduce the difficulty of designing an algorithm program required to generate a target signal while effectively ensuring that the parasitic capacitor can be quickly charged.

[0062] Optionally, the potential value of the target signal in each overcharging sub-stage decreases in sequence with the order in which each overcharging sub-stage is entered.

[0063] When the number of overcharge sub-stages is N (N is greater than or equal to 1), and the target signal passes through the 1st overcharge sub-stage to the Nth overcharge sub-stage in the high potential stage, the potential value of the target signal in the Nth overcharge sub-stage is defined as the Nth preset high potential value VN, that is, the 1st preset high potential value V1 to the Nth preset high potential value VN decrease in sequence. It can be understood that when the Nth overcharge sub-stage ends, if the high potential stage has not ended, the potential value of the target signal is restored to its corresponding preset high potential value V0 in the high potential stage. In this way, each overcharge sub-stage can charge the parasitic capacitor with a stepped high potential value, which is beneficial to improve the parasitic capacitor charging efficiency while reducing the energy consumption of the self-luminous display panel.

[0064] Optionally, when the target signal enters the high potential stage, it enters the overcharge sub-stage with the maximum potential. In this way, after the target signal enters the high potential stage, the parasitic capacitor is first charged with the maximum preset high potential, which is beneficial to further improve the charging efficiency of the target signal on the parasitic capacitor.

[0065] Optionally, each overcharge sub-stage in a high potential stage is distributed in a continuous manner, that is, after the target signal enters the high potential stage, it first passes through the first overcharge sub-stage to the Nth overcharge sub-stage in sequence. Figure 2 In the embodiments B and C shown, the total duration from the 1st overcharge substage to the Nth overcharge substage is less than the total duration of the high potential stage, that is, after the Nth overcharge substage, the potential value of the target signal is restored to the preset high potential value V0 corresponding to the high potential stage and maintained until the high potential stage ends. In this way, compared with the discrete distribution of each overcharge substage, a more standard step-type high potential value can be used to charge the parasitic capacitor, which is conducive to further improving the parasitic capacitor charging efficiency and reducing the energy consumption of the self-luminous display panel.

[0066] Embodiment 2

[0067] The present application also proposes a self-luminous display panel, which includes a self-luminous device OLED and a display driving circuit. The specific structure of the display driving circuit refers to the above embodiment. Since the present self-luminous display panel adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here. Among them, the display driving circuit is connected to the self-luminous device OLED.

[0068] Embodiment 3

[0069] The present application also proposes a display device, which includes a self-luminous display panel. The specific structure of the self-luminous display panel refers to the above-mentioned embodiment. Since the display device panel adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0070] The above description is only an optional embodiment of the present application, and does not limit the patent scope of the present application. All equivalent structural transformations made by using the contents of the present application specification and drawings under the inventive concept of the present application, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A display driving circuit, applied to a self-luminous display panel, wherein the self-luminous display panel comprises a self-luminous device, characterized in that: The display driving circuit comprises: A first thin film transistor, a controlled end for receiving a scan signal, and an input end for receiving a data signal; a second thin film transistor, a controlled end of which is connected to the output end of the first thin film transistor; A signal conversion circuit, the input end of which is used to receive a scanning signal, and the signal conversion circuit is used to perform potential inversion on the scanning signal to generate a light emitting control signal and then output it; and A light-emitting control circuit, wherein a controlled end is connected to the output end of the signal conversion circuit, a first input end is used to access a power supply voltage, a second input end is connected to the output end of the second thin-film transistor, a first output end is connected to the input end of the second thin-film transistor, and an output end is connected to the self-luminous device; The light emitting control circuit is used for outputting the power supply voltage to the self-luminous device via the second thin film transistor when receiving a light emitting control signal of a first preset potential; The light emitting control circuit comprises: a third thin film transistor, whose input terminal is used to access a power supply voltage, and whose output terminal is connected to the input terminal of the second thin film transistor; a fourth thin film transistor, whose input end is connected to the output end of the second thin film transistor, and whose output end is connected to the self-luminous device; The fifth thin film transistor has a controlled end connected to the output end of the signal conversion circuit, an input end for receiving a light-emitting driving signal, and an output end connected to the controlled ends of the third thin film transistor and the fourth thin film transistor respectively.

2. The display driving circuit according to claim 1, characterized in that: The target signal has a high potential phase and a low potential phase that are entered alternately; wherein the high potential phase includes at least one overcharge sub-phase, and the potential value of the target signal in any overcharge sub-phase is greater than the preset high potential value corresponding to the target signal in the high potential phase; Wherein, the target signal is the data signal and / or the light-emitting driving signal.

3. The display driving circuit according to claim 2, characterized in that: The potential value of the target signal in each of the overcharging sub-stages decreases in sequence with the entry order of each of the overcharging sub-stages.

4. The display driving circuit according to claim 3, characterized in that: When the target signal enters the high potential stage, it enters the overcharge sub-stage with the maximum potential.

5. The display driving circuit according to claim 3, characterized in that: The overcharge sub-stages in a high potential stage are distributed in a continuous manner.

6. The display driving circuit according to any one of claims 1 to 5, characterized in that: The scanning signal has a potential opposite to that of the light emission control signal.

7. A self-luminous display panel, characterized in that: The self-luminous display panel comprises: Self-luminous device; and The display driving circuit according to any one of claims 1 to 6, wherein the display driving circuit is connected to the self-luminous device.

8. A display device, characterized in that: The display device comprises the self-luminous display panel as claimed in claim 7.

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