Patent ID: 7876293

Claim:
An image display system, comprising: a pixel driving circuit, comprising: a storage capacitor coupled between a first node and a second node; a first switch receiving a first signal and turned on in a first period and a second period; a second switch coupled to the first node and turned on in the first period and the second period; a third switch coupled between the second node and the first switch and turned on in the first period, a third period and a fourth period; a fourth switch coupled between the second switch and a first voltage and turned on in the first period, the third period and the fourth period; a fifth switch coupled between the second node and the first voltage and turned on in the first period, the second period and the third period; a sixth switch coupled between the first node and a reference voltage and turned on in the fourth period; a seventh switch comprising a transistor having a gate coupled to the first switch, a source coupled to the second switch and a drain and turned on in the fourth period, wherein the voltage between the source and the gate of the transistor is a threshold voltage in the second period; and an electroluminescent element coupled between the drain of the transistor and a second voltage and emitting light in the fourth period.