A system and method for setting one or more compensation coefficients for a transistor. In some embodiments, a method for setting a first compensation coefficient for a transistor includes: determining a plurality of measured transistor currents, each at a respective one of a plurality of transistor control voltages; setting the first compensation coefficient based on the measured transistor currents and the transistor control voltages; and adjusting a voltage applied to a gate of the transistor based on the first compensation coefficient, the voltage corresponding to a color value.

A display device includes a sensing circuit and a controller which selects a pixel row in a frame period. A vertical blank period of the frame period includes a sensing time in which the sensing circuit performs a sensing operation for the selected pixel row. The sensing circuit measures a first source voltage of a driving transistor of a pixel in the selected pixel row at a first time point of the sensing time, and measures a second source voltage of the driving transistor at a second time point of the sensing time. The controller calculates a threshold voltage parameter and a mobility parameter based on the first and second source voltages, predicts a saturated source voltage of the driving transistor based on the threshold voltage parameter and the mobility parameter, and calculates a threshold voltage of the driving transistor based on the saturated source voltage.

An organic light emitting display device includes pixels, a sensor configured to extract at least one of deviation information of first transistors of the pixels and deterioration information of OLEDs of the pixels in a sensing period, and a converter configured to change a bit of first data input from the outside by using at least one of the deviation information and the deterioration information, and to generate second data, wherein a pixel at an ith horizontal line includes an OLED, a first transistor configured to control an amount of a current that flows from a first power source via the OLED in response to a voltage of a first node, second and third transistors configured to turn on when a scan signal is supplied to an ith scan line, and a fourth transistor configured to turn on when a control signal is supplied to an ith control line.

A pixel circuit for an active matrix organic light emitting diode (AMOLED) and other active matrix displays is disclosed. The pixel circuit is programmed by the voltage supplied through a data line. An electrical current through a light emitting device for a known LED voltage and a pixel current for a pixel programed with a known data signal can be measured by a readout circuit through the data line. A 7T1C implementation enables to pre-charge the drive transistor to a reference voltage in each drive cycle, and to pre-set the light emitting device to a reference voltage prior to emission in each cycle.

A method of compensating for degradation of a display device includes sensing a first sensing current flowing through a sensing line connected to a pixel, which includes a programming period for writing a data voltage of a predetermined color to a storage capacitor of the pixel, sensing a sensing voltage of the sensing line, which includes a period for charging a line capacitor connected to the sensing line, estimating a voltage of an anode electrode of an organic light emitting diode using a second sensing current estimated from the first sensing current and the sensing voltage, and determining a degradation compensation value using the voltage of the anode electrode.

An organic light-emitting display device includes a data driver which supplies a data voltage to a data line of each sub-pixel, and senses a driving voltage of each sub-pixel through each sensing line connected to a sub-pixel, and generates sensed data based on the driving voltage of each sub-pixel. Further, the organic light-emitting display device includes a controller that generates a reference parameter for compensating for each of operation characteristics of each sub-pixel using the sensed data generated from the data driver, and compensates for image data based on the reference parameter and outputs the compensated image data. The controller controls the gate driver and the data driver so that sensed data is additionally generated, and compensates for and outputs the image data based on a compensation parameter extracted based on the additionally generated sensed data, thereby controlling execution of external compensation based on temperature and deterioration characteristics.

A pixel circuit and a display device including the pixel circuit are disclosed. The pixel circuit according to embodiments includes a first pixel circuit connected in parallel to an initialization voltage line to which an initialization voltage is applied, and including a first-first switch element connected to a first-first gate line and a first-second switch element connected to a first-second gate line; and a second pixel circuit connected in parallel to the initialization voltage line, and including a second-first switch element connected to a second-first gate line and a second-second switch element connected to a second-second gate line, and the first-second gate line and the second-first gate line are electrically connected.

External compensation of display panels may employ measurement or sensing circuitry configured to measure the output of a pixel and compensate for variations. Due to effects from the sensing circuitry, a mismatch between a target current and the actual current in the pixel may occur. Systems and methods that compensate for the effects from sensing circuitry and reduce or mitigate the mismatch are described. Systems and methods described herein include compensation circuitry that is capable of employing correction factors to compensate for the effects due to the presence of sensing circuitry. Methods for determining the correction factor are also described.

A voltage-programmed display system allows measurement of effects on pixels in a panel that includes both active pixels and reference pixels coupled to a supply line and a programming line. The reference pixels are controlled so that they are not subject to substantial changes due to aging and operating conditions over time. A readout circuit is coupled to the active pixels and the reference pixels for reading at least one of current, voltage or charge from the pixels when they are supplied with known input signals. The readout circuit is subject to changes due to aging and operating conditions over time, but the readout values from the reference pixels are used to adjust the readout values from the active pixels to compensate for the unwanted effects.

A display device includes a display unit including gate lines and pixels electrically coupled to the gate lines; a timing controller configured to generate an on-clock signal, an off-clock signal, an enable signal, and a common signal; a clock generator configured to generate a plurality of clock signals having different phases based on the on-clock signal and the off-clock signal, when the enable signal has a first voltage level, wherein the clock generator is to insert a common pulse into each of the plurality of clock signals based on the common signal, when the enable signal has a second voltage level different from the first voltage level; and a gate driver configured to generate gate signals based on the plurality of clock signals, and to sequentially provide the gate signals to the gate lines.