Disclosure of Invention
The invention provides a display driving method, a display driver and a display device, which at least partially solve the technical problems in the prior art.
According to a first aspect of the present invention, there is provided a display driving method for driving a light emitting diode display panel, the light emitting diode display panel including a plurality of gate lines, a plurality of data lines, a plurality of emission control lines, and a plurality of pixel units, each of the pixel units being connected to one of the gate lines, one of the emission control lines, and one of the data lines, the pixel units including a driving transistor, a light emitting diode, and an emission control transistor, a first electrode and a second electrode of the driving transistor, a cathode and an anode of the light emitting diode, and a first electrode and a second electrode of the emission control transistor being connected in series in a same current path, the emission control line being configured to control on/off of the corresponding emission control transistor, and to provide a first driving signal to a pixel unit connected to at least one of the gate lines in at least one frame period of the pixel unit, the frame period of the first driving signal is divided into a first writing stage, a first lighting stage and a blanking stage, and the first driving signal includes: in the first writing stage, providing effective voltage to the grid lines and the data lines, and providing invalid voltage to the light-emitting control lines corresponding to the grid lines so as to write data voltage into the pixel units; in the first light-emitting stage, providing an invalid voltage to the grid line, and providing an effective voltage to a light-emitting control line corresponding to the grid line so as to enable the pixel unit to emit light; and in the extinguishing stage, providing an invalid voltage to the light-emitting control line corresponding to the grid line so as to extinguish the pixel unit.
Optionally, in a frame period of the first driving signal, the blanking period is located after the first light-emitting period.
Optionally, in a frame period of the first driving signal, a ratio of a duration of the blanking period to a duration of the frame period is less than or equal to 0.2.
Optionally, the first driving signal is provided to each of the pixel units during the display of the same frame of picture.
Optionally, the display driving method further includes a step of determining whether to provide the first driving signal to each of the pixel units for a current frame image, where if an average brightness of the current frame image is smaller than a first threshold, the first driving signal is provided to each of the pixel units; otherwise, providing a second driving signal to each pixel unit, wherein a frame period of the second driving signal is divided into a second writing stage and a second light-emitting stage, and the second driving signal provided to the pixel unit connected to any gate line comprises: in the second writing stage, providing effective voltage to the grid lines and the data lines, and providing ineffective voltage to the light-emitting control lines corresponding to the grid lines so as to write data voltage to the pixel units connected with the grid lines; and in the second light-emitting stage, providing an invalid voltage for the grid line and providing an effective voltage for the light-emitting control line corresponding to the grid line so as to enable the pixel unit connected with the grid line to emit light.
Optionally, in a case that it is determined that the first driving signal is provided to each of the pixel units, the display driving method further includes setting the blanking period duration, where the blanking period duration is determined according to a preset mapping relationship between an average gray scale of the current frame image and the blanking period duration, and the blanking period duration is gradually increased as the average gray scale decreases.
According to a second aspect of the present invention, there is provided a display driver for driving an led display panel, the led display panel including a plurality of gate lines, a plurality of data lines, a plurality of emission control lines, and a plurality of pixel units, each pixel unit being connected to one gate line, one emission control line, and one data line, the pixel unit including a driving transistor, an led, and an emission control transistor, a first electrode and a second electrode of the driving transistor, a cathode and an anode of the led, and a first electrode and a second electrode of the emission control transistor being connected in series in a same current path, the emission control line being configured to control on/off of the corresponding emission control transistor, the display driver including a driving output module, the driving output module being connected to the gate lines, the data lines, and the pixel units, The light-emitting control lines are connected, the driving output module is configured to provide a first driving signal to a pixel unit connected to at least one gate line in at least one frame period of the pixel unit, the frame period of the first driving signal is divided into a first writing stage, a first light-emitting stage and a blanking stage, and the first driving signal includes: in the first writing stage, providing effective voltage to the grid lines and the data lines, and providing invalid voltage to the light-emitting control lines corresponding to the grid lines so as to write data voltage into the pixel units; in the first light-emitting stage, providing an invalid voltage to the grid line, and providing an effective voltage to a light-emitting control line corresponding to the grid line so as to enable the pixel unit to emit light; and in the extinguishing stage, providing an invalid voltage to the light-emitting control line corresponding to the grid line so as to extinguish the pixel unit.
Optionally, in a frame period of the first driving signal, the blanking period is located after the first light-emitting period.
Optionally, in a frame period of the first driving signal, a ratio of a duration of the blanking period to a duration of the frame period is less than or equal to 0.2.
Optionally, the drive output module is configured to: and in the display process of the same frame of picture, providing the first driving signal to each pixel unit.
Optionally, the display driver further comprises a configuration module configured to: judging whether the current frame image is provided with the first driving signals to each pixel unit, wherein if the average brightness of the current frame image is smaller than a first threshold value, a first instruction is output to the driving output module so that the driving output module provides the first driving signals to each pixel unit; otherwise, outputting a second switching instruction to the drive output module; the driving output module is configured to provide a second driving signal to each pixel unit under the condition of receiving the second instruction, the frame period of the second driving signal is divided into a second writing phase and a second light-emitting phase, and the second driving signal provided to the pixel unit connected to any gate line includes: in the second writing stage, providing effective voltage to the grid lines and the data lines, and providing ineffective voltage to the light-emitting control lines corresponding to the grid lines so as to write data voltage to the pixel units connected with the grid lines; and in the second light-emitting stage, providing an invalid voltage for the grid line and providing an effective voltage for the light-emitting control line corresponding to the grid line so as to enable the pixel unit connected with the grid line to emit light.
Optionally, the configuration module is further configured to: and setting the extinguishing stage time length under the condition that the average brightness of the current frame image is smaller than a first threshold, wherein the extinguishing stage time length is determined when the current frame image is displayed according to the mapping relation between the preset average gray scale of the current frame image and the extinguishing stage time length, and the extinguishing stage time length is gradually increased along with the reduction of the average gray scale of all the sub-pixels.
And providing a display driver comprising a memory storing instructions and a processor executing the instructions to perform a display driving method according to the first aspect of the invention.
According to a third aspect of the present invention, there is provided a display device comprising a light emitting diode display panel and a display driver for driving the light emitting diode display panel, the display driver being the display driver of the second aspect of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
The embodiment of the invention provides a display driving method for driving a light emitting diode D1 display panel. Specific examples of the led D1 display panel include an oled D1 display panel and a qd led D1 display panel.
As shown in fig. 1, the led D1 display panel includes a plurality of gate lines GL, a plurality of data lines DL, a plurality of emission control lines EML, and a plurality of pixel units. The pixel cells may be arranged in a matrix, the gate lines GL may extend in a row direction, the data lines DL may extend in a column direction, and the emission control lines EML may extend in a row direction. Each pixel unit is connected to one gate line GL, one emission control line EML, and one data line DL. For example, one row of pixel units is connected to the same gate line GL and the same emission control line EML. The pixel units in the same column are connected to the same data line DL.
The pixel unit includes a driving transistor T0, a light emitting diode D1, and a light emission controlling transistor T2. Of course, to implement the writing of the display data and the storage of the display data, the pixel unit further includes a writing control crystal T1 and a first capacitor C1. The first and second poles of the driving transistor T0, the cathode and anode of the light emitting diode D1, and the first and second poles of the emission control transistor T2 are all connected in series in the same current path, and the emission control line EML is used to control the on/off of the corresponding emission control transistor T2.
Taking the oled D1 as an example, the oled display panel includes a red oled, a green oled, and a blue oled. In particular, the embodiments of the present invention are also applicable to an organic light emitting diode display panel (also referred to as a WOLED display panel) in which a white organic light emitting diode is matched with a red, green and blue color film. This is because the organic functional layer of the white organic light emitting diode is also formed by combining a red organic light emitting substance, a green organic light emitting substance, and a blue organic light emitting substance.
In the display driving method according to the embodiment of the invention, the pixel unit connected to at least one gate line GL is provided with the first driving signal in at least one frame period of the pixel unit. Referring to fig. 2 in conjunction with fig. 1 and 3, a frame period in which the first driving signal is located is divided into a first writing phase, a first lighting phase, and a blanking phase. As an example, each transistor in fig. 1 is an N-type thin film transistor, and the effective voltage of each signal in fig. 3 is a high level voltage. Fig. 3 shows a timing of supplying the first driving signal to the pixel unit connected to one gate line GL in one frame period. In fig. 3, a signal supplied to the gate line GL is denoted by G, a signal supplied to the data line DL is denoted by D, and a signal supplied to the emission control line EML is denoted by EM.
For the gate line GL under consideration, in the first writing phase P1, an active voltage is supplied to the gate line GL and each data line DL, and an inactive voltage is supplied to the emission control line EML corresponding to the gate line GL, so as to write a data voltage to the pixel cell. At this time, the write control transistor T1 is turned on, and the data voltage on the data line DL is stored to the gate of the driving transistor T0 and the first pole of the first capacitor C1 (the pole connected to the driving transistor T0). The light emitting control transistor T2 is turned off, and no current flows through the current path of the light emitting diode D1. The light emitting diode D1 did not emit light.
In the first light emitting period P2, an inactive voltage is supplied to the gate line GL, and an active voltage is supplied to the light emitting control line EML corresponding to the gate line GL, so that the pixel cell emits light. At this time, the write control transistor T1 is turned off, and the gate voltage of the driving transistor T0 is not affected regardless of whether there is a signal on the data line DL. A current path from the first power terminal VDD to the second power terminal VSS through the source drain (i.e., the first and second electrodes thereof) of the light emission controlling transistor T2, the source drain (and the first and second electrodes thereof) of the driving transistor T0, the anode and cathode of the light emitting diode D1 is turned on in this order, so that the light emitting diode D1 emits light. The pixel cell displays light of a desired brightness.
In the turn-off period P3, an inactive voltage is supplied to the emission control line EML corresponding to the gate line GL to turn off the pixel cell. The light emission controlling transistors T2 are all off at this time, and the pixel cell does not emit light. Of course, in order to reduce the conventional driving timing and the corresponding hardware modification, the gate line GL is supplied with the inactive voltage (the same as in the case of the lighting phase P2) and the data lines DL are supplied with the inactive voltage (the same as in the case of the lighting phase P2) in the turn-off phase P3.
Since the light emitting time of the pixel cell connected to the currently considered gate line GL is shortened relative to the prior art in one frame period. This also retards the aging rate of the light-emitting layers therein, thereby retarding the color shift caused by the aging of the light-emitting layers of the respective colors being too fast.
Alternatively, the extinguishing phase P3 is positioned after the first lighting phase P2 within the frame period of the first driving signal. I.e. for the currently considered row of pixel cells, it is first illuminated and then extinguished within the same frame period. Of course, the extinguishing phase P3 can also precede the first lighting phase P2. That is, for the currently considered row of pixel cells, in the same frame period, after the writing of the data voltage is completed, the light is not emitted, and after a period of time, the light is emitted again.
Optionally, the ratio of the duration of the blanking period P3 to the duration of the adjustment frame period in the frame period of the first driving signal is less than or equal to 0.2. The extinguishing period P3 is too long and causes noticeable flicker, so that the extinguishing period P3 needs to be set short.
Alternatively, the first driving signal is provided to each pixel unit during the display of the same frame of picture. That is, if the driving timings of the pixel units on the gate lines GL need to be adjusted, the driving timings of the pixel units on all the gate lines GL are adjusted the same. This may simplify the complexity of the led D1 display panel and the display driver.
Optionally, the display driving method further includes a step of determining whether to provide a first driving signal to each pixel unit for the current frame image, where if the average brightness of the current frame image is smaller than a first threshold, the first driving signal is provided to each pixel unit; otherwise, a second driving signal is provided to each pixel unit, the frame period of the second driving signal is divided into a second writing stage and a second light-emitting stage, and the second driving signal provided to the pixel unit connected to any gate line GL includes: in the second writing phase P1a, an effective voltage is supplied to the gate line GL and each data line DL, and an ineffective voltage is supplied to the emission control line EML corresponding to the gate line L, so as to write a data voltage to the pixel cell connected to the gate line GL; in the second light-emitting period P2a, an inactive voltage is provided to the gate line GL, and an active voltage is provided to the light-emitting control line EML corresponding to the gate line GL, so that the pixel cell connected to the gate line GL emits light.
For a brighter display image, if the pixel unit connected to each gate line has a longer non-light-emitting time in one frame period, the overall flicker feeling is more serious. Whereas for a darker displayed image the overall flicker perception will be relatively weak. If the light-off period P3 is set for a dark display screen, the light-off period P3 is not set for a dark display screen. Namely, for a part of frame images, the display driving is performed by adopting the optimized driving method, and for another part of frame images, the display driving is performed by adopting a conventional driving method. The judgment is based on the average gray level (i.e. the overall brightness) of all the sub-pixels. If the overall brightness of one frame of image to be displayed is higher, flicker felt by a user is more obvious, and a conventional driving timing sequence is adopted. If the overall brightness of the image of one frame to be displayed is low, flicker sensed by a user is not obvious, and the optimized driving time sequence is adopted.
Under the condition that the first driving signals are provided for each pixel unit, the display driving method further comprises the step of setting the duration of the extinguishing stage, wherein the duration of the extinguishing stage when the current frame image is displayed is determined according to the preset mapping relation between the average gray scale of the current frame image and the duration of the extinguishing stage, and the duration of the extinguishing stage is gradually increased along with the reduction of the average gray scale.
That is, the lower the overall brightness of the picture to be displayed, the longer the light-off period P3 lasts in the frame period in which each row of pixel units is located. On the premise that the flicker felt by the user is not obvious, the light-emitting time of the light-emitting layer is shortened as much as possible, and the aging is delayed as much as possible.
Referring to fig. 4 in combination with fig. 1 and 3, an embodiment of the invention further provides a display driver for driving a light emitting diode D1 display panel, where the light emitting diode D1 display panel includes a plurality of gate lines GL, a plurality of data lines DL, a plurality of light emitting control lines EML and a plurality of pixel units, each pixel unit is connected to one gate line GL, one light emitting control line EML and one data line DL, each pixel unit includes a driving transistor T0, a light emitting diode D1 and a light emitting control transistor T2, a first pole and a second pole of the driving transistor T0, a cathode and an anode of the light emitting diode D1 and a first pole and a second pole of the light emitting control transistor T2 are all connected in series in the same current path, and the light emitting control line EML is used for controlling on and off of the corresponding light emitting control transistor T2. The display driver is used to implement the display driving method, and the principle and details of the operation of each specific structure can be referred to the description in the previous section.
The display driver includes a driving output module 200, the driving output module 200 is connected to the gate lines GLGL, the data lines DLDL and the light emitting control lines EMLEML, and configured to provide a first driving signal to a pixel unit connected to at least one gate line GL in at least one frame period of the pixel unit, the frame period of the first driving signal is divided into a first writing period, a first light emitting period and a light off period, and the first driving signal includes: in the first writing stage, an effective voltage is provided to the gate line GL and each data line DL, and an ineffective voltage is provided to the light emitting control line EML corresponding to the gate line GL, so as to write a data voltage to the pixel unit; in the first light-emitting stage, an invalid voltage is provided to the gate line GL, and an effective voltage is provided to the light-emitting control line EML corresponding to the gate line GL, so that the pixel unit emits light; in the turn-off period, an inactive voltage is supplied to the emission control line EML corresponding to the gate line GL, so that the pixel unit is turned off.
Optionally, the blanking period is located after the first light-emitting period in the frame period of the first driving signal.
Optionally, in the frame period of the first driving signal, a ratio of a duration of the blanking period to a duration of the frame period is less than or equal to 0.2.
Optionally, the drive output module 200 is configured to: in the display process of the same frame of picture, a first driving signal is provided for each pixel unit.
Optionally, the display driver further comprises a configuration module 100 configured to: judging whether a first driving signal is provided for each pixel unit or not for a current frame image, wherein if the average brightness of the current frame image is smaller than a first threshold value, a first instruction is output to the driving output module 200, so that the driving output module 200 provides the first driving signal for each pixel unit; otherwise, outputting a second instruction to the driving output module 200; the driving output module 200 is configured to provide a second driving signal to each pixel unit when receiving a second instruction, where a frame period of the second driving signal is divided into a second writing phase and a second light emitting phase, and the second driving signal provided to the pixel unit connected to any gate line GL includes: in the second writing stage, an effective voltage is provided to the gate line GL and each data line DL, and an ineffective voltage is provided to the light-emitting control line EML corresponding to the gate line GL, so as to write a data voltage to the pixel unit connected to the gate line GL; in the second light-emitting stage, an inactive voltage is provided to the gate line GL, and an active voltage is provided to the light-emitting control line EML corresponding to the gate line GL, so that the pixel unit connected to the gate line GL emits light.
Optionally, the configuration module 100 is further configured to: and under the condition that the average brightness of the current frame image is smaller than a first threshold value, setting the duration of a blanking stage, wherein the duration of the blanking stage when the current frame image is displayed is determined according to the preset mapping relation between the average gray scale of the current frame image and the duration of the blanking stage, and the duration of the blanking stage is gradually increased along with the reduction of the average gray scale of all the sub-pixels.
Of course, the configuration module 100 and the driving output module 200 in the display driver may be integrated into the same driving chip, or may be distributed into a plurality of driving chips (for example, distributed into a source driving chip, a gate driving chip, a timing control chip, etc.)
Referring to fig. 5 in conjunction with fig. 1 and 3, an embodiment of the present invention further provides a display driver, which includes a memory 300 and a processor 400, wherein the memory 300 stores instructions, and the processor 400 executes the instructions to perform the aforementioned display driving method.
Specifically, the memory 300 is any device having a storage function, such as a read only memory 300(ROM), a random access memory 300(RAM), or the like. The processor 400 is, for example, a microprocessor 400(MCU), a central processing unit 400(CPU), or the like. Of course, the memory 300 and the processor 400 may be integrated in the same device.
The embodiment of the present invention further provides a display device, which includes a light emitting diode D1 display panel and a display driver for driving the light emitting diode D1 display panel, where the display driver is the aforementioned display driver.
The display device is any product or component having a display function, such as an organic light emitting diode D1 display module, a quantum dot light emitting diode D1 display module, a mobile phone, a display and the like.
It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.