Controller, display device and driving method
According to embodiments of the present disclosure, there may be provided a controller, a display device and a driving method. In consideration of that a hysteresis by an image data voltage supplied to a subpixel during an active time may exert an influence on a real-time sensing process, by correcting a reference sensing driving data voltage on the basis of an offset voltage, it is possible to correct the influence of a hysteresis exerted on sensing of the characteristic value of a driving transistor.
1 . A display device, comprising:
a plurality of data lines;
a plurality of reference voltage lines; and
a plurality of subpixels connected to the plurality of data lines and the plurality of reference voltage lines,
wherein the plurality of data lines include a first data line which is connected to a first subpixel among the plurality of subpixels, and the plurality of reference voltage lines include a first reference voltage line which is connected to the first subpixel,
wherein the first subpixel includes a first light emitting element, a first driving transistor, a first scan transistor and a first sensing transistor, a first node of the first driving transistor is electrically connectable to the first data line through the first scan transistor, and a second node of the first driving transistor is electrically connectable to the first reference voltage line through the first sensing transistor,
wherein an image data voltage is supplied to the first subpixel during an active time, and
wherein a sensing driving data voltage is supplied to the first subpixel during a blank time different from the active time, and the sensing driving data voltage is variable depending on the image data voltage,
wherein the sensing driving data voltage is configured to be obtained by offset-processing a reference sensing driving data voltage by an offset voltage, and the offset voltage corresponds to the image data voltage, and
wherein the offset voltage comprises:
a first offset voltage corresponding to a first image data voltage for expressing a low grayscale; and
a second offset voltage corresponding to a second image data voltage for expressing a high grayscale,
wherein the sensing driving data voltage obtained by correcting the reference sensing driving data voltage with the first offset voltage and the sensing driving data voltage obtained by correcting the reference sensing driving data voltage with the second offset voltage have different voltage levels.
2 . The display device of claim 1 , wherein the offset voltage is variable based on a hysteresis related to the image data voltage supplied to the first subpixel during the active time.
3 . The display device of claim 2 , wherein the offset voltage is configured to be greater in response to the hysteresis being greater.
4 . The display device of claim 1 , comprising a memory configured to store a value of the offset voltage determined before the blank time.
5 . The display device of claim 1 , wherein a voltage rising speed of the second node of the first driving transistor after a sensing driving data voltage corrected based on the first offset voltage is supplied is same as a voltage rising speed of the second node of the first driving transistor after a sensing driving data voltage corrected based on the second offset voltage is supplied.
6 . The display device of claim 1 , comprising a sensing transistor configured to sense, n during the blank time, a characteristic value of the first driving transistor for the first subpixel.
7 . The display device of claim 6 , wherein during the blank time, a voltage rising speed of the second node of the first driving transistor corresponds to a mobility of the first driving transistor.
8 . The display device of claim 1 , further comprising:
a data driving circuit configured to supply a corrected sensing driving data voltage to the first data line,
wherein the data driving circuit comprises:
an analog-to-digital converter for sensing a voltage of the first reference voltage line;
a sampling switch configured to control connection between the first reference voltage line and the analog-to-digital converter; and
an initialization switch configured to control connection between a sensing driving reference voltage supply node supplied with the sensing driving reference voltage and the first reference voltage line.
9 . A method for driving a display device, comprising:
setting a sensing driving data voltage;
by supplying the sensing driving data voltage to a first node of a driving transistor and supplying a sensing driving reference voltage to a second node of the driving transistor, initializing the first node and the second node of the driving transistor;
by floating the second node of the driving transistor, changing a voltage of the second node of the driving transistor; and
after a predetermined time elapses from a time point at which a voltage of the second node of the driving transistor is changed, sampling a voltage of the second node of the driving transistor,
wherein the setting the sensing driving data voltage is performed after an image data voltage is supplied to a first subpixel during an active time, and
wherein, in the initializing the first node and the second node of the driving transistor, the sensing driving data voltage is variable depending on the image data voltage,
wherein the sensing driving data voltage is set by offset-processing a reference sensing driving data voltage by an offset voltage, and the offset voltage corresponds to the image data voltage,
wherein the offset voltage include:
a first offset voltage corresponding to a first image data voltage for expressing a low grayscale; and
a second offset voltage corresponding to a second image data voltage for expressing a high grayscale, and
wherein the sensing driving data voltage obtained by correcting the reference sensing driving data voltage with the first offset voltage and the sensing driving data voltage obtained by correcting the reference sensing driving data voltage with the second offset voltage have different voltage levels.
10 . A controller, comprising:
a control signal output unit configured to output a data control signal to a data driving circuit; and
a data output unit configured to output data to the data driving circuit,
wherein the data output unit outputs, during an active time, image data to be supplied to a first subpixel among a plurality of subpixels disposed in a display panel, and
wherein the data output unit outputs, during a blank time different from the active time, sensing driving data to be supplied to the first subpixel, and the sensing driving data is variable based on the image data,
wherein the sensing driving data is obtained by offset-processing reference sensing driving data by an offset voltage, and
the offset voltage corresponds to an image data voltage obtained by converting the image data into an analog form, and
wherein the offset voltage comprises:
a first offset voltage corresponding to a first image data voltage for expressing a low grayscale; and
a second offset voltage corresponding to a second image data voltage for expressing a high grayscale,
wherein the sensing driving data voltage obtained by correcting the reference sensing driving data voltage with the first offset voltage and the sensing driving data voltage obtained by correcting the reference sensing driving data voltage with the second offset voltage have different voltage levels.
11 . The controller of claim 10 , wherein the offset voltage is variable based on a hysteresis related to the image data voltage to be supplied to the first subpixel during the active time.