Pixel driving circuit and driving method thereof, display panel
AssigneeShenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
InventorsQikun Liu, Jiexin Zheng
Life of this patent
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Abstract
A pixel driving circuit and a driving method thereof, and a display panel are provided. The pixel driving circuit includes a first transistor (T1), a second transistor (T2), a third transistor (T3), a first storage capacitor (Cst1), a second storage capacitor (Cst2) and an organic light emitting element (OLED). By appropriately designing capacitance of the two capacitors and dividing a gate voltage of the first transistor (T1), it can be ensured that a black screen is achieved and contrast of a display panel is improved even though a negative drift is seriously caused on a threshold voltage of T1.
Claims8
A pixel driving circuit, comprising:
- a first transistor (T1), a gate of the first transistor (T1) connected to a first node (A), a source of the first transistor (T1) connected to a second node (B), a drain of the first transistor (T1) fed by a power source voltage (Vdd);
- a second transistor (T2), the gate of the second transistor (T2) connected to a third node (C) and fed by a writing signal (WR), the source of the second transistor (T2) fed by a data signal (Data), the drain of the second transistor (T2) connected to the second node (B);
- a third transistor (T3), the gate of the third transistor (T3) fed by a reading signal (RD), the source of the third transistor (T3) connected to the second node (B), the drain of the third transistor (T3) connected to a reference voltage (Vref);
- a first storage capacitor (Cst1), one end of which is connected to the third node (C) and the other end of which is connected to the first node (A);
- a second storage capacitor (Cst2), one end of which is connected to the first node (A) and the other end of which is connected to the second node (B);
- and
- an organic light emitting element (OLED), an anode of which is connected to the second node (B) and a cathode of which is connected to a common ground voltage (Vss),
- wherein the pixel driving circuit is driven at a plurality of stages comprising:
- an initial stage, at which the pixel driving circuit is initialized;
- a data input stage, at which an external integrated circuit (IC) provides a voltage to the data signal (Data), the voltage is divided by using the first storage capacitor (Cst1) and the second storage capacitor (Cst2), and the voltage is pulled down and written to the gate of the first transistor (T1);
- and
- a light emission stage, at which the pixel driving circuit provides a driving current which is provided to the organic light emitting element (OLED) for driving the organic light emitting element (OLED) to emit light for displaying images,
- wherein at the data input stage, the writing signal (WR), the reading signal (RD), the data signal (Data) and the reference voltage (Vref) obtain a high voltage level, all of the first transistor (T1), the second transistor (T2) and the third transistor (T3) are turned on, and the second storage capacitor (Cst2) is charged.
Dependencies are inferred from the claim text.