Patent Application
20200090591
The present application claims a priority of the Chinese patent application No. 201810401414.3 filed on Apr. 28, 2018, which is incorporated herein by reference in its entirety.
The present disclosure relates to the field of display technology, in particular to a pixel driving circuit, a driving method thereof and a display device.
Currently, when an image displayed by a commonly-used Active-Matrix Organic Light-Emitting Diode (AMOLED) display device, as a maintenance-type display device, includes an object that moves rapidly, due to an effect of persistence of vision for a human eye, a position of the object perceived by the viewer's brain is different from a position of the object displayed on the AMOLED display device. At this time, a dynamic ghost is generated on the AMOLED display device, and thereby the user experience is adversely affected.
In one aspect, the present disclosure provides in some embodiments a pixel driving circuit for driving a light-emitting unit, including: a driving unit connected to the light-emitting unit; a capacitor unit, one end of which is connected to the driving unit, and a second end of which is connected to a power source signal input end; a data write-in unit connected to a corresponding gate line, a corresponding data line and the driving unit; a power source control unit connected to a first light-emitting control end, the power source signal input end and the driving unit; and a first light-emitting control unit connected to a second light-emitting control end, the power source signal input end and the driving unit, and configured to, within a predetermined time period of a light-emitting stage, control the power source signal input end to be electrically connected to the driving unit under the control of the second light-emitting control end, stop the operation of the driving unit, and enable the light-emitting unit not to emit light.
In a possible embodiment of the present disclosure, the driving unit includes a driving transistor, a first electrode of which is connected to the light-emitting unit. The first end of the capacitor unit and the data write-in unit are connected to a gate electrode of the driving transistor. The power source control unit is connected to a second electrode of the driving transistor. The first light-emitting control unit is connected to the gate electrode of the driving transistor, and further configured to, within the predetermined time period of the light-emitting stage, control the power source signal input end to be electrically connected to the gate electrode of the driving transistor under the control of the second light-emitting control end.
In a possible embodiment of the present disclosure, the driving unit includes a driving transistor, a first electrode of which is connected to the light-emitting unit. The first end of the capacitor unit is connected to a gate electrode of the driving unit. The data write-in unit and the power source control unit are connected to a second electrode of the driving transistor. The first light-emitting control unit is connected to the gate electrode of the driving transistor, and further configured to, within the predetermined time period of the light-emitting stage, control the power source signal input end to be electrically connected to the gate electrode of the driving transistor under the control of the second light-emitting control end. The pixel driving circuit further includes: a first resetting unit connected to a resetting control end, the gate electrode of the driving transistor and a reference signal input end, and configured to control the gate electrode of the driving transistor to be electrically connected to, or electrically disconnected from, the reference signal input end under the control of the resetting control end; and a compensation unit connected to the corresponding gate line, the gate electrode of the driving transistor and the first electrode of the driving transistor, and configured to control the gate electrode of the driving transistor to be electrically connected to, or electrically disconnected from, the first electrode of the driving transistor under the control of the corresponding gate line.
In a possible embodiment of the present disclosure, the pixel driving circuit further includes: a second resetting unit connected to the corresponding gate line, the light-emitting unit and the reference signal input end, and configured to control the light-emitting unit to be electrically connected to, or electrically disconnected from, the reference signal input end under the control of the corresponding gate line; and a second light-emitting control unit, the driving transistor being connected to the light-emitting unit via the first electrode of the second light-emitting control unit, the second light-emitting control unit being connected to the first light-emitting control end, the first electrode of the driving transistor and the light-emitting unit, and configured to control the first electrode of the driving transistor to be electrically connected to, or electrically disconnected from, the light-emitting unit under the control of the first light-emitting control end.
In a possible embodiment of the present disclosure, the predetermined time period is a time period between a predetermined time point and an ending time point. The ending time point is a time point where the light-emitting stage is ended. The predetermined time point is any time point between T/16+D and T/4+D, where D represents a start time point of the light-emitting stage, and T represents a frame of time for display.
In a possible embodiment of the present disclosure, the data write-in unit includes a first switching transistor, a gate electrode of which is connected to the corresponding gate line, a first electrode of which is connected to the gate electrode of the driving transistor, and a second electrode of which is connected to the corresponding data line. The power source control unit includes a second switching transistor, a gate electrode of which is connected to the first light-emitting control end, a first electrode of which is connected to the second electrode of the driving transistor, and a second electrode of which is connected to the power source signal input end. The first light-emitting control unit includes a third switching transistor, a gate electrode of which is connected to the second light-emitting control end, a first electrode of which is connected to the power source signal input end, and a second electrode of which is connected to the gate electrode of the driving transistor.
In a possible embodiment of the present disclosure, the power source control unit includes a second switching transistor, a gate electrode of which is connected to the first light-emitting control end, a first electrode of which is connected to the second electrode of the driving transistor, and a second electrode of which is connected to the power source signal input end. The first light-emitting control unit includes a third switching transistor, a gate electrode of which is connected to the second light-emitting control end, a first electrode of which is connected to the power source signal input end, and a second electrode of which is connected to the gate electrode of the driving transistor. The first resetting unit includes a fourth switching transistor, a gate electrode of which is connected to the resetting control end, a first electrode of which is connected to the gate electrode of the driving transistor, and a second electrode of which is connected to the reference signal input end. The second resetting unit includes a fifth switching transistor, a gate electrode of which is connected to the corresponding gate line, a first electrode of which is connected to the light-emitting unit, and a second electrode of which is connected to the reference signal input end. The compensation unit includes a sixth switching transistor, a gate electrode of which is connected to the corresponding gate line, a first electrode of which is connected to the gate electrode of the driving transistor, and a second electrode of which is connected to the first electrode of the driving transistor. The second light-emitting control unit includes a seventh switching transistor, a gate electrode of which is connected to the first light-emitting control end, a first electrode of which is connected to the light-emitting unit, and a second electrode of which is connected to the first electrode of the driving transistor. The data write-in unit includes an eighth switching transistor, a gate electrode of which is connected to the corresponding gate line, a first electrode of which is connected to the second electrode of the driving transistor, and a second electrode of which is connected to the corresponding data line.
In another aspect, the present disclosure provides in some embodiments a method of driving the above-mentioned pixel driving circuit, including, within a predetermined time period of a light-emitting stage, controlling, by a first light-emitting control unit, a power source signal input end to be electrically connected to a driving unit under the control of a second light-emitting control end, stop the operation of the driving unit, and enable a light-emitting unit not to emit light.
In yet another aspect, the present disclosure provides in some embodiments a display device including N above-mentioned pixel driving circuits, where N is a positive integer.
In a possible embodiment of the present disclosure, the display device further includes: N pixel units arranged in a matrix form and in X rows, the pixel units corresponding to the pixel driving circuits respectively; X gate lines corresponding to the X rows of pixel units respectively; and X light-emitting control lines corresponding to the X rows of pixel units respectively, a first light-emitting control end being connected to a corresponding light-emitting control line. A second light-emitting control end is connected to an Mth gate line randomly selected from an (X/16+C)th gate line to an (X/4+C)th gate line, or connected to an Mth light-emitting control line randomly selected from an (X/16+C)th light-emitting control line to an (X/4+C)th light-emitting control line, where C has a value acquired by subtracting 1 from the number of rows corresponding to the second light-emitting control end. When M is greater than X, the second light-emitting control end is connected to an (M−X)th gate line or an (M−X)th light-emitting control line.
The following drawings are provided to facilitate the understanding of the present disclosure, and constitute a portion of the description. These drawings and the following embodiments are for illustrative purposes only, but shall not be construed as limiting the present disclosure. In these drawings,
The present disclosure will be described hereinafter in conjunction with the drawings and embodiments.
In the related art, when an image displayed by a display device includes an object that moves rapidly, due to an effect of persistence of vision for a human eye, a position of the object perceived by the viewer's brain is different from a position of the object displayed on the display device. At this time, a dynamic ghost is generated on the display device, and thereby the user experience is adversely affected. To be specific, as shown in
As shown in
As shown in
At a data write-in stage T1, a data voltage Vdata may be applied to the corresponding data line Data, and a gate driving signal may be applied to the corresponding gate line Gate. The data write-in unit 3 may be in an operating state under the control of the gate driving signal, so as to enable the corresponding data line Data to be electrically connected to the driving unit 1, thereby to write the data voltage Vdata into the driving unit 1 and store the data voltage Vdata in the capacitor unit 2.
Within an actual light-emitting time period T2 of the light-emitting stage, the power source control unit 4 may be in an operating state under the control of the first light-emitting control end EM1, so as to enable the power source signal input end ELVDD to be electrically connected to the driving unit 1, thereby to transmit a power source signal from the power source signal input end ELVDD to the driving unit 1. At this time, the driving unit 1 may be in an operating state under the control of the data voltage and the power source signal, so as to drive the light-emitting unit 10 to emit light.
Within the predetermined time period T3 of the light-emitting stage, the first light-emitting control unit 5 may control the power source signal input end ELVDD to be electrically connected to the driving unit 1 under the control of the second light-emitting control end EM2, so as to disable the driving unit 1, thereby to enable the light-emitting unit 10 not to emit light.
On the basis of the structure of the pixel driving circuit and the procedure of driving the light-emitting unit 10 to emit light, the light-emitting unit 10 may be controlled to emit light after the light-emitting stage begins, and controlled not to emit light within the predetermined time period T3 of the light-emitting stage. As a result, it is able to reduce a light-emitting duty ratio of the light-emitting unit 10 and reduce a retention time of each image, thereby to prevent the occurrence of dynamic ghosts.
A double-sided arrow in the dynamic region 101 in each of
In a possible embodiment of the present disclosure, as shown in
When the driving unit 1 includes the driving transistor DTFT, there may exist various connection modes for the pixel driving circuit. Some of the connection modes will be given, and corresponding operation procedures will be described hereinafter.
In a first connection mode, as shown in
To be specific, as shown in
At the data write-in stage T1, as shown in
Within the actual light-emitting time period T2 of the light-emitting stage, as shown in
Within the predetermined time period T3 of the light-emitting stage, as shown in
In a possible embodiment of the present disclosure, in the first connection mode, the data write-in unit 3, the power source control unit 4 and the first light-emitting control unit 5 may each be of various structures. As shown in
It should be appreciated that, when the data write-in unit 3 is in the operating state, the first switching transistor M1 may be turned on, and when the data write-in unit 3 is not in the operating state, the first switching transistor M1 may be turned off. When the power source control unit 4 is in the operating state, the first switching transistor M2 may be turned on, and when the power source control unit 4 is not in the operating state, the second switching transistor M2 may be turned off. When the first light-emitting control unit 5 is in the operating state, the third switching transistor M3 may be turned on, and when the first light-emitting control unit 5 is not in the operating state, the third transistor M3 may be turned off.
In a second connection mode, as shown in
In the second connection mode, the pixel driving circuit may further include a first resetting unit 6 and a compensation unit 7. The first resetting unit 6 may be connected to a resetting control end Reset, the gate electrode of the driving transistor DTFT and a reference signal input end Vref, and configured to control the gate electrode of the driving transistor DTFT to be electrically connected to, or electrically disconnected from, the reference signal input end Vref under the control of the resetting control end Reset. The compensation unit 7 may be connected to the corresponding gate line Gate, and the gate electrode and the first electrode of the driving transistor DTFT, and configured to control the gate electrode of the driving transistor DTFT to be electrically connected to, or electrically disconnected from, the first electrode of the driving transistor DTFT under the control of the corresponding gate line Gate.
To be specific, as shown in
At a resetting stage T0, a reference voltage may be applied to the reference signal input end Vref. The first resetting unit 6 may control the gate electrode of the driving transistor DTFT to be electrically connected to the reference signal input end Vref under the control of the resetting control end Reset, so as to enable a potential at the gate electrode of the driving transistor DTFT to be the reference voltage. The power source control unit 4 may not be in the operating state under the control of the first light-emitting control end EM1, so as to control the power source signal input end ELVDD to be electrically disconnected from the second electrode of the driving transistor DTFT.
At the data write-in stage T1, the driving transistor DTFT may be turned on under the control of the reference voltage. The first resetting unit 6 may control the gate electrode of the driving transistor DTFT to be electrically disconnected from the reference signal input end Vref under the control of the resetting control end Reset. The power source control unit 4 may not be in the operating state under the control of the first light-emitting control end EM1, so it may continuously control the power source signal input end ELVDD to be electrically disconnected from the second electrode of the driving transistor DTFT. A data voltage may be applied to the corresponding data line Data, and a gate driving signal may be applied to the corresponding gate line Gate. The data write-in unit 3 may be in the operating state under the control of the gate driving signal, so as to enable the corresponding data line Data to be electrically connected to the second electrode of the driving transistor DTFT. In addition, the compensation unit 7 may be in an operating state under the control of the gate driving signal, so as to control the gate electrode of the driving transistor DTFT to be electrically connected to, or electrically disconnected from, the first electrode of the driving transistor DTFT, thereby to write the data voltage Vdata into the gate electrode of the driving transistor DTFT through the data write-in unit 3, the driving transistor DTFT and the compensation unit 7 until a voltage applied to the gate electrode of the driving transistor DTFT is equal to Vdata+Vth (where Vth represents a threshold voltage of the driving transistor DTFT), and store Vdata+Vth in the capacitor unit 2.
Within the actual light-emitting time period T2 of the light-emitting stage, the data write-in unit 3 and the compensation unit 7 may each not be in the operating state under the control of the corresponding gate line Gate. The power source control unit 4 may be in the operating state under the control of the first light-emitting control end EM1, so as to control the power source signal input end ELVDD to be electrically connected to the second electrode of the driving transistor DTFT, thereby to apply the power source signal from the power source signal input end ELVDD to the second electrode of the driving transistor DTFT. At this time, the driving transistor DTFT may be turned on under the control of the potential at the gate electrode of the driving transistor DTFT (i.e., Vdata+Vth) and the power source signal, so as to drive the light-emitting unit 10 to emit light.
Within the predetermined time period T3 of the light-emitting stage, the first light-emitting control unit 5 may control the power source signal input end ELVDD to be electrically connected to the gate electrode of the driving transistor DTFT under the control of the second light-emitting control end EM2, so as to turn off the driving transistor DTFT, thereby to enable the light-emitting unit 10 not to emit light.
In a possible embodiment of the present disclosure, as shown in
To be specific, when the pixel diving circuit further includes the second resetting unit 8 and the second light-emitting control unit 9, the operation procedure of the pixel driving circuit will be described as follows.
At the data write-in state T1, the second resetting unit 8 may control the light-emitting unit 10 to be electrically connected to the reference signal input end Vref under the control of the corresponding gate line Gate, so as to reset the light-emitting unit 10. At the stages other than data write-in stage, the second resetting unit 8 may control the light-emitting unit 10 to be electrically disconnected from the reference signal input end Vref under the control of the corresponding gate line Gate.
At the light-emitting stage (including T2 and T3), the second light-emitting control unit 9 may control the first electrode of the driving transistor DTFT to be electrically connected to the light-emitting unit 10 under the control of the first light-emitting control end EM1. At the resetting stage T0 and the data write-in stage T1, the second light-emitting control unit 9 may control the first electrode of the driving transistor DTFT to be electrically connected to the light-emitting unit 10 under the control of the first light-emitting control end EM1.
It should be appreciated that, the light-emitting unit 10 maybe an OLED, an anode of which is connected to the second resetting unit 8.
In a possible embodiment of the present disclosure, as shown in
In a possible embodiment of the present disclosure, the predetermined time period T3 may be a time period between a predetermined time point and an ending time point. The ending time point may be a time point where the light-emitting stage is ended. The predetermined time point may be any time point between T/16+D and T/4+D, where D represents a start time point of the light-emitting stage, and T represents a frame.
To be specific, the light-emitting stage may include the actual light-emitting time period T2 and the predetermined time period T3. Within the light-emitting time period T2, the light-emitting unit 10 may emit light, and within the predetermined time period T3, the light-emitting unit 10 may not emit light. A range of the predetermined time period T3 may be set according to the practical need, as long as it is able for the viewer to clearly view each image and it is able to prevent the occurrence of the ghosts. In a possible embodiment of the present disclosure, the predetermined time period may be any time point Y between T/16+D and T/4+D, and the ending time point may be a time point where the light-emitting stage is ended, i.e., the actual light-emitting time period T2 may be between the start time point of the light-emitting stage and the time point Y, and the predetermined time period T3 may be between the time point Y and the ending time point of the light-emitting stage.
It should be appreciated that, the pixel driving circuit has been described hereinabove merely on the basis of the above-mentioned circuit structure. In some other embodiments of the present disclosure, each unit of the pixel driving circuit may also be of any other structure, which will not be particularly defined herein. In addition, the driving transistor DTFT and the switching transistors may each be a TFT, a field effect transistor (FET) or any other element having a same characteristic. In order to differentiate two electrodes other than a gate electrode from each other, one of the two electrodes is called as first electrode and the other is called as second electrode. In actual use, the first electrode may be a drain electrode while the second electrode may be a source electrode, or the first electrode may be a source electrode while the second electrode may be a drain electrode. In addition, the driving transistor DTFT and the switching transistors may each be an N-type or a P-type transistor according to the practical need.
The present disclosure further provides in some embodiments a method of driving the above-mentioned pixel driving circuit, which includes: at the data write-in stage T1, applying a data voltage to the corresponding data line Data, and applying a gate driving signal to a corresponding gate line Gate, so as to control the data write-in unit 3 to be in an operating state under the control of the gate driving signal and control the corresponding data line Data to be electrically connected to the driving unit 1, thereby to write the data voltage into the driving unit 1 and store the data voltage in the capacitor unit 2; within the actual light-emitting time period T2 of the light-emitting stage, controlling the power source control unit 4 to be in an operating state under the control of the first light-emitting control end EM1, so as to control the power source signal input end ELVDD to be electrically connected to the driving unit 1, transmit a power source signal from the power source signal input end ELVDD to the driving unit 1, and enable the driving unit 1 to be in the operating state under the control of the data voltage and the power source signal, thereby to drive the light-emitting unit 10 to emit light; and within the predetermined time period T3 of the light-emitting stage, controlling, by the first light-emitting control unit 5, the power source signal input end ELVDD to be electrically connected to the driving unit 1 under the control of the second light-emitting control end EM2, thereby to disable the driving unit 1 and enable the light-emitting unit 10 not to emit light.
On the basis of the driving procedure of the pixel driving circuit, the light-emitting unit 10 may emit light after the light-emitting stage begins, and the light-emitting unit 10 may not emit light within the predetermined time period T3 of the light-emitting stage. As a result, it is able to reduce a light-emitting duty ratio of the light-emitting unit 10 and reduce a retention time of each image, thereby to prevent the occurrence of dynamic ghosts.
The present disclosure further provides in some embodiments a display device including N above-mentioned pixel driving circuits, where N is a positive integer.
When the pixel driving circuit drives the light-emitting unit 10 to emit light, it is able to prevent the occurrence of ghosts. Hence, when the display device includes the above-mentioned pixel driving circuit, it is also able to prevent the occurrence of dynamic ghosts when an image is displayed, thereby to improve a display effect of the display device.
In a possible embodiment of the present disclosure, the display device may further include: N pixel units 300 arranged in a matrix form and in X rows (as shown in
To be specific, the display device may include X gate lines, and each gate line may be connected to the data write-in unit 3 of a corresponding pixel driving circuit. The display device may further include X light-emitting control lines, and each light-emitting control line may be connected to the power source control unit 4 of the corresponding pixel driving circuit, i.e., the first light-emitting control end EM1 connected to the power source control unit 4 may be connected to a corresponding light-emitting control line.
In a possible embodiment of the present disclosure, in order to prevent the introduction of any other additional signal line into the display device, the second light-emitting control end EM2 connected to the first light-emitting control unit 5 of the pixel driving circuit may be connected to the corresponding gate line or light-emitting control line of the display device according to the practical need. For example, the second light-emitting control end EM2 may be connected to the Mth gate line randomly selected from the (X/16+C)th gate line to the (X/4+C)th gate line, or connected to an Mth light-emitting control line randomly selected from the (X/16+C)th light-emitting control line to the (X/4+C)th light-emitting control line. In addition, when M is greater than X, the second light-emitting control end EM2 may be connected to the (M−X)th gate line or the (M−X)th light-emitting control line.
More specifically, a connection mode of the second light-emitting control end EM2 may be determined in accordance with a type of the third switching transistor M3 of the first light-emitting control unit 5. For example, when the third switching transistor is an N-type transistor, the second light-emitting control end EM2 may be connected to the corresponding light-emitting control line, so as to control an on state and an off state of the third switching transistor M3 through the corresponding light-emitting control line. When the third switching transistor is a P-type transistor, the second light-emitting control end EM2 may be connected to the corresponding gate line, so as to control the on state and the off state of the third switching transistor M3 through the corresponding gate line.
A connection relationship of the display device will be described hereinafter illustratively. As shown in
It should be appreciated that, the features, structures or materials may be combined in any embodiment or embodiments in an appropriate manner.
The above embodiments are for illustrative purposes only, but the present disclosure is not limited thereto. Obviously, a person skilled in the art may make further modifications and improvements without departing from the spirit of the present disclosure, and these modifications and improvements shall also fall within the scope of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201810401414.3 | Apr 2018 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2019/083223 | 4/18/2019 | WO | 00 |
