Abstract: An active TFT circuit structure with current scaling function is disclosed, which includes a current source, a data line, a scan line, a direct current voltage source, capacitors and four transistors, wherein the capacitors form a cascade structure. During the ON-state, the two of the transistors are turn-on based on the voltage provided by the scan line, so that the data current provided by the current source flows through the data line-and the transistor which is one of the opened transistors, thereby arriving an emitting light element and the transistor connected to the emitting light element. When the pixel circuit changes from ON- to OFF-state, the voltage of the node between the storage capacitors reduces due to the feed-through effect of one of storage capacitor, thereby reducing the driving current of the emitting light element. Therefore, it can be achieved the current scaling function.

Abstract: A pixel circuit including a first transistor, a coupling capacitor, a second transistor, and a luminescent element is provided. The first transistor is used as a switch. The coupling capacitor stores a coupling voltage and transmits the coupling voltage to the gate of the second transistor for compensating a drift of the threshold voltage of the second transistor. The second transistor provides a driving current for driving the luminescent element to emit light.

Abstract: An active TFT circuit structure with current scaling function is disclosed, which includes a current source, a data line, a scan line, a direct current voltage source, capacitors and four transistors, wherein the capacitors form a cascade structure. During the ON-state, the two of the transistors are turn-on based on the voltage provided by the scan line, so that the data current provided by the current source flows the data line and the transistor which is one of the opened transistors, thereby arriving an emitting light element and the transistor connected to the emitting light element. When the pixel circuit changes from ON- to OFF-state, the voltage of the node between the storage capacitors reduces due to the feed-through effect of one of storage capacitor, thereby reducing the driving current of the emitting light element. Therefore, it can be achieved the current scaling function.