This application claims priority to Korean Patent Application No. 10-2020-0030883, filed on Mar. 12, 2020, and all the benefits accruing therefrom under 35 U.S.C. § 119, the content of which in its entirety is herein incorporated by reference.

BACKGROUND

(a) Field

Embodiments of the invention relate to a display device, and more particularly, to a display device and a driving method thereof.

(b) Description of the Related Art

As information technology has developed, the importance of a display device, which is a connection medium between a user and information, has been highlighted. Accordingly, the use of display devices such as a liquid crystal display device, an organic light emitting display device, and a plasma display device has been increasing.

In a display device, each pixel may emit light with a luminance corresponding to a data voltage supplied thereto through a data line. The display device may display an image frame by a combination of light emitted from the pixels.

Each of the pixels may be connected to a corresponding data line. Accordingly, a scan driver may be used to supply a scan signal for selecting a pixel to which a data voltage is supplied among the pixels. The scan driver may include a shift register to sequentially supply a scan signal of a turn-on level in units of a scan line.

In addition, as necessary, a receiving line may be connected to the plurality of pixels in order to sense a mobility and a threshold voltage characteristic of a driving transistor of the pixel, and a deterioration characteristic of a light emitting element, and the like.

SUMMARY

Embodiment of the invention are directed to a display device that may sense a voltage drop corresponding to wire resistance of a data line and a receiving line, correct a threshold voltage sensed at each pixel, and externally compensate the data signal by the corrected threshold voltage and supply the compensated data signal to each pixel.

Embodiments of the invention are directed to a driving method of the display device.

An embodiment of the invention provides a display device including: a display panel including a plurality of pixels; a scan driver which supplies a scan signal to a plurality of scan lines connected to the pixels and supplies a sensing signal to a plurality of sensing lines connected to the pixels; a data driver which supplies a data signal corresponding to image data to a plurality of data lines connected to the pixels; a sensing part which senses a threshold voltage of a first transistor included in each of the pixels through a plurality of receiving lines connected to the pixels, and corrects the sensed threshold voltage based on a voltage drop corresponding to at least one of an internal resistance of the data lines and an internal resistance of the receiving lines; and a timing controller which generates the image data by changing input image data based on a corrected threshold voltage.

In an embodiment, the sensing part may include a threshold voltage sensing part which senses the threshold voltage of the first transistor; a voltage drop sensing part which senses the voltage drop for at least two selected pixels among target pixels connected to a j-th data line and a j-th receiving line among the pixels, and which calculates the voltage drop for each of the target pixels by using a sensed voltage drop, where j is a positive integer; an offset voltage calculator which calculates an offset voltage compensating for the voltage drop; and an offset voltage adder which adds and outputs the threshold voltage sensed for the target pixels to the offset voltage.

In an embodiment, the at least two selected pixels may include a first pixel disposed on a first horizontal line of the display panel and a second pixel disposed on a last horizontal line of the display panel.

In an embodiment, the sensing part and the data driver may be disposed at a same side of the display panel.

In an embodiment, the scan driver may supply the scan signal and the sensing signal to a scan line and a sensing line which are connected to the first pixel, respectively, and the data driver may supply a reference voltage determined based on the threshold voltage sensed for the first pixel to a data line connected to the first pixel.

In an embodiment, the reference voltage may be a voltage obtained by adding a voltage of a first power source and a threshold voltage sensed for the first transistor of the first pixel.

In an embodiment, the voltage drop sensed for the at least two selected pixels may include a voltage drop corresponding to an internal resistance of a line to which the first power source is applied.

In an embodiment, the voltage drop sensing part may calculate a maximum voltage drop by differentiating a first voltage drop sensed for the first pixel and a second voltage drop sensed for the second pixel.

In an embodiment, the voltage drop sensing part may calculate the voltage drop for each of the target pixels by interpolating the maximum voltage drop based on a number of horizontal lines in which the pixels are disposed.

In an embodiment, each of the target pixels may include the first transistor connected between a first power source and a second node, where the first transistor may include a gate electrode connected to a first node; a second transistor connected between the j-th data line and the first node, where the second transistor may include a gate electrode connected to a corresponding one of the scan lines; a third transistor connected between the second node and a third node connected to the j-th receiving line, where the third transistor may include a gate electrode connected to a corresponding one of the sensing lines; a storage capacitor connected between the first node and the second node; and a light emitting element including a first electrode connected to the second node and a second electrode connected to a second power source.

In an embodiment, the display panel may further include a sensing capacitor connected between a ground and a fourth node connected through the j-th receiving line to the third node. In such an embodiment, the sensing capacitor may store a voltage applied to the fourth node and transmit a stored voltage to the sensing part.

In an embodiment, the voltage drop sensing part may senses the voltage drop for the at least two selected pixels based on a voltage transmitted from the sensing capacitor.

Another embodiment of the invention provides a driving method of a display device, including: sensing a threshold voltage of a first transistor included in each of a plurality of pixels of the display device through a plurality of receiving lines connected to the pixels; calculating a voltage drop corresponding to an internal resistance of a plurality of data lines and the receiving lines connected to the pixels; correcting a sensed threshold voltage based on a calculated voltage drop; and generating image data based on a corrected threshold voltage and supplying a data signal corresponding to the image data to the data lines.

In an embodiment, the calculating the voltage drop may include sensing a voltage drop for at least two selected pixels among target pixels connected to a j-th data line and a j-th receiving line, where j is a positive integer; calculating a voltage drop for each of the target pixels by using the sensed voltage drop; calculating an offset voltage which compensates for a calculated voltage drop; and adding and outputting the offset voltage and the threshold voltage sensed for the target pixels.

In an embodiment, the at least two selected pixels may include a first pixel disposed on a first horizontal line of a display panel and a second pixel disposed on a last horizontal line of the display panel.

In an embodiment, the sensing the voltage drop for the at least two selected pixels may include supplying a scan signal and a sensing signal to a scan line and a sensing line which are connected to the first pixel, respectively, and supplying a reference voltage determined based on a threshold voltage sensed for the first pixel to a data line connected to the first pixel.

In an embodiment, the reference voltage may be a voltage obtained by adding a voltage of a first power source and a threshold voltage sensed for the first transistor of the first pixel.

In an embodiment, the voltage drop for the at least two selected pixels may include a voltage drop corresponding to an internal resistance of a line to which the first power source is applied.

In an embodiment, the calculating the voltage drop for each of the target pixels may include calculating a maximum voltage drop by differentiating a first voltage drop sensed for a first pixel and a second voltage drop sensed for the second pixel from each other.

In an embodiment, the calculating the voltage drop for each of the target pixels may include calculating a voltage drop for each of the target pixels by interpolating the maximum voltage drop based on a number of horizontal lines in which the pixels are disposed.

According to embodiments of the display device and the driving method thereof according to the invention, a voltage drop corresponding to wire resistance of a data line and a receiving line is effectively sensed to correct a threshold voltage sensed at each pixel.

In such embodiments, a threshold voltage error due to the wire resistance of the data line and the receiving line may be reduced, such that performance of externally compensating a threshold voltage for a driving transistor of each pixel may be further improved.

