32results about How to "Compensation for Threshold Voltage Variations" patented technology

The invention provides an AMOLED pixel driving circuit and a pixel driving method. The AMOLED pixel driving circuit adopts a 3T1C structure and comprises a first thin film transistor (T1), a second thin film transistor (T2), a third thin film transistor (T3), a storage capacitor (Cs) and an organic light emitting diode ( OLED). A second scanning signal voltage (Vsel2) is introduced. The third thin film transistor (T3) provides an initial low potential (Vini) of a data signal voltage (VData) for the first thin film transistor (T1) which is a source electrode driving the thin film transistors at a reset phase so that a threshold voltage change driving the thin film transistors can be effectively compensated and a complexity of a power supply voltage signal is reduced.

An organic light emitting diode display includes: a display unit (130) including: a plurality of scan lines (S1, ..., Sn); a plurality of light emission control lines (GC1, ..., GCn); a plurality of data lines (D1, ..., Dm); and a plurality of pixels (140), each of the pixels (140) being coupled to a corresponding scan line (S1, ..., Sn) among the scan lines (S1, ..., Sn), a corresponding light emission control line (GC1, ..., GCn) among the light emission control lines (GC1, ..., GCn), and a corresponding data line (D1, ..., Dm) among the data lines (D1, ..., Dm); a scan driver (110) configured to transmit a plurality of scan signals (Scan(n-1), Scan(n)) to the scan lines (S1, ..., Sn); a light emission driver (160) configured to transmit a plurality of light emission control signals (GC(t)) to the light emission control lines (GC1, ..., GCn); a data driver (120) configured to transmit a plurality of data signals (Data(t)) to the data lines (D1, ..., Dm); and a power source driver (170) configured to apply a plurality of power source voltages having different levels to the pixels (140) during one frame period.

A display device includes: a display unit including pixels coupled to scan lines for transmitting scan signals, data lines for transmitting data signals, and light emission control lines for transmitting light emission control signals; a scan driver; a data driver; and a light emission driver. Each pixel includes: an OLED; a driving transistor to transmit a driving current corresponding to a data signal to the OLED; a first transistor to transmit the data signal to the driving transistor according to a first scan signal; a second transistor to apply a first power source voltage to a first electrode of the driving transistor according to a second scan signal, during an initialization period for initializing a gate electrode voltage of the driving transistor; and a capacitor including a first electrode coupled to a gate electrode of the driving transistor and a second electrode coupled to a first power source supply.

A shift register includes a plurality of stages cascade-connected with each other. Each stage includes a pull-up circuit, a pull-up driving circuit, and a pull-down circuit. The pull-up circuit coupled to a first clock signal is used for providing an output signal. The pull-up driving circuit includes a control circuit and a first transistor. The control circuit has a gate coupled to a previous stage, and a drain coupled to a second clock signal. The first transistor includes a gate coupled to the source of the control circuit, a drain coupled to a driving end of the previous stage, and a source coupled to a first input end. The pull-down circuit pulls down voltage on the first input end.

A pixel circuit for a display device includes a drive transistor configured to control an amount of current to a light-emitting device depending upon a voltage applied to a gate of the drive transistor; a second transistor connected to the gate of the drive transistor and a second terminal of the drive transistor, such that when the second transistor is in an on state the drive transistor becomes diode-connected such that the gate and the second terminal of the drive transistor are connected through the second transistor; a light-emitting device that is connected at a first node to a third terminal of the drive transistor and at a second node to a first voltage supply; a third transistor connected to the first node of the light-emitting device, which connects a data voltage to the first node of the light-emitting device; a fourth transistor that is connected between the second terminal of the drive transistor and a second voltage supply; and at least one capacitor having a first plate that is connected to the gate of the drive transistor and a second plate that is connectable to a reference signal. The pixel circuit is operable during a phase preceding the emission phase including applying a data voltage to the first node of the light-emitting device and the third terminal of the drive transistor, the data voltage being set so that a voltage across the light-emitting device is lower than a threshold voltage of the light emitting device.

The invention discloses an AMOLED pixel driver circuit and pixel driving method, by using a pixel driver circuit of 3T2C structure to effectively compensate threshold voltage of driving TFT in each pixel; through adding a third TFT (T3) and introducing control signal voltage (Vc) to control the third TFT (T3) to prevent current from flowing through in the threshold voltage detection phase and threshold voltage compensation phase so as to reduce the complexity of the power supply (Vdd); by adding a second capacitor (C2) to regulate the influence on the source voltage of the driving TFT by the data signal voltage (VData) so as to reduce the data signal complexity. As a result, the data signal only needs to switch once.

A pixel circuit includes a drive transistor that controls an amount of current to a light-emitting device, and a second transistor connected to the gate of the drive transistor and a second terminal of the drive transistor, such that when the second transistor is in an on state the drive transistor becomes diode-connected. A threshold voltage of the drive transistor is compensated during a compensation phase while the drive transistor is diode connected. The light-emitting device is connected between the drive transistor and at a second node to a first voltage input. The pixel circuit further includes a storage capacitor having a first plate connected to the gate of the drive transistor, and a programming capacitor having a first plate connected to a second plate of the storage capacitor, and a second plate of the programming capacitor is electrically connected to a data voltage input during a data programming phase. The second plate of the storage capacitor and the first plate of the programming capacitor are connectable to a reference voltage to perform the compensation phase independently of the programming phase, and the storage capacitor and the programming capacitor are series connected during the emission phase.

The invention discloses an AMOLED pixel driver circuit and pixel driving method, by using a pixel driver circuit of 4T1C or 4T2C structure to effectively compensate threshold voltage of driving TFT in each pixel; through adding a third TFT (T3) and a fourth TFT (T4) and introducing the first scan signal (SEL1) to control the third TFT (T3) and the fourth TFT (T4) to respectively writing the initialization signal (INI) to initialize the gate and the source of the driving TFT in reset phase so as to reduce the complexity of the power supply signal so that the circuit can use DC power supply directly; by adding a second capacitor (C2) to regulate the influence on the source voltage of the driving TFT by the data signal (DATA) so as to reduce the data signal complexity. As a result, the data signal only needs to switch once.