Display device and driving method
According to embodiments of the present disclosure, there may be provided a display device and a driving method. During a first type sensing time period during display driving, a voltage difference between a first node and a second node of a driving transistor is set to correspond to a threshold voltage stored in a memory, whereby it is possible to compensate for, in real time period, threshold voltage variations of driving transistors.
1. A display device comprising:
a plurality of data lines;
a plurality of reference voltage lines; and
a plurality of subpixels electrically connected to the plurality of data lines and the plurality of reference voltage lines,
wherein the plurality of data lines includes a first data line which is electrically 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 electrically 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, and
wherein, a first period for driving the first sub-pixel includes an initialization period, a tracking period, and a sampling period, and
in the initialization period, a voltage difference between a sensing driving data voltage supplied to the first data line and a sensing driving reference voltage supplied to the first reference voltage line is set to correspond to a threshold voltage of the first driving transistor in the first subpixel identified from threshold voltage-related information stored in a memory, and
in the tracking period that proceeds after the initialization period, a voltage of the second node of the first driving transistor increases, and
in the sampling period that proceeds after the tracking period, the voltage of the second node of the first driving transistor is supplied to the first reference voltage line.
2. The display device of claim 1 , wherein the first period is included in a blank time period between active time periods.
3. The display device of claim 1 , wherein, before the first period for the first subpixel proceeds, a threshold voltage sensing time period for sensing a threshold voltage of the first driving transistor proceeds, and as the threshold voltage sensing time period proceeds, the threshold voltage-related information is stored or updated in the memory.
4. The display device of claim 3 , wherein a threshold voltage of the first driving transistor during the first period has a voltage value lower than a threshold voltage of the first driving transistor during the threshold voltage sensing time period before the first period.
5. The display device of claim 3 , wherein, during the first period for a second subpixel different from the first subpixel, a voltage of a second node of a second driving transistor included in the second subpixel does not vary or varies within a selected level.
6. The display device of claim 5 , wherein a threshold voltage of the second driving transistor during the first period for the second subpixel has a voltage value the same as or greater than a threshold voltage of the second driving transistor during the threshold voltage sensing time period before the first period for the second subpixel.
7. The display device of claim 1 , further comprising:
a data driving circuit configured to supply the sensing driving data voltage to the first data line,
wherein the data driving circuit comprises:
an analog-to-digital converter configured to sense 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.
8. The display device of claim 2 , wherein
the first period proceeds during a first blank time period,
a second period for a second subpixel proceeds during a second blank time period different from the first blank time period, and
during the second period, a voltage of a second node of a second driving transistor included in the second subpixel rises and before a voltage of the second node of the second driving transistor rises, a voltage difference between a sensing driving data voltage supplied to a corresponding data line and a sensing driving reference voltage supplied to a corresponding reference voltage line does not correspond to a threshold voltage of the second driving transistor in the second subpixel identified from the threshold voltage-related information stored in the memory.
9. The display device of claim 8 , wherein, during the second period, a voltage rising speed of the second node of the second driving transistor corresponds to a mobility of the second driving transistor.