RELATED APPLICATIONS

This application claims priority to Taiwan Application Serial Number 108103363, filed Jan. 29, 2019, which is herein incorporated by reference in its entirety.

BACKGROUND

Field of Invention

The present of the disclosure relates to a display device. More particularly, the present disclosure relates to a pixel circuit of a display device.

Description of Related Art

With the advance of technology, consumers are increasingly demanding the quality of display devices. Under this requirement, when a display device wants to display a target brightness during a frame time, in general, to provide a normal driving current of a light-emitting element (such as a light-emitting diode) and a long emission ratio in order to cause the human eye to generate a brightness integral to sense a perceived target brightness. However, in this driving mode, the response time of the light-emitting element reaching the target brightness is long, and consumers may easily experience the phenomenon of motion blur. The shorter the driving current given to the light-emitting element, the shorter the reaction time for the light-emitting element to reach the target brightness. However, when driven by a large current, the display device must be adjusted to have a lower illumination ratio in a frame time to maintain the same target brightness sensed by the human eye. If the illumination ratio has a time frame which is too low, the human eye will easily notice that the display device is flickering.

It can be seen that the above existing methods obviously have inconveniences and defects, and need to be improved. In order to solve the above problems, the relevant fields have tried their best to find a solution, but for a long time, no suitable solution has been developed.

SUMMARY

One aspect of the present disclosure is a pixel circuit. The pixel circuit includes a first switch, a capacitor, a driving transistor, a driving transistor and a light-emitting diode (LED). The first switch is configured to output a data voltage in response to a scan signal. A first terminal of the capacitor and the first switch are coupled to a node, a second terminal of the capacitor is configured to receive a reference signal. The driving transistor is coupled to the node, the driving transistor outputs a current according to a voltage of the node. The LED is coupled to the driving transistor, the LED emits light according to the current. The data voltage is written to the node by the first switch, the reference signal is changed to different voltages during different operation periods, the capacitor couples a voltage difference between the different voltages to the node according to the reference signal, the driving transistor outputs a first current respectively according to the data voltage and the voltage difference, and outputs a second current according to the data voltage during different operation periods, such that the LED emits a first brightness light according to the first current and emits a second brightness light according to the second current during different operation periods.

Another aspect of the present disclosure is a pixel circuit. The pixel circuit includes a first switch, a capacitor, a driving transistor and a light emitting diode (LED). A first terminal of the capacitor and the first switch are coupled to a node, a second terminal of the capacitor is configured to receive a reference signal. The driving transistor is coupled to the node, the driving transistor outputs a current according to a voltage of the node. The LED is coupled to the driving transistor, the LED emits light according to the current. In a first period, the first switch outputs a data voltage to the node in response to a scan signal, and the reference voltage comprises a first voltage, in a second period, the reference signal comprises a second voltage, the driving transistor outputs a first current to the LED according to the voltage of the node, in a third period, the reference signal comprises the first voltage, the driving transistor outputs a second current to the LED according to the voltage of the node.

Therefore, according to the technical content of the present disclosure, the embodiment of the present disclosure provides a pixel circuit. The different current is provided by the adjustment of the reference signal under the same data voltage. Once the pixel circuit provides a large current by the above technical features, the response time can be shortened, and the field of the pixel circuit application of the present disclosure becomes wider. When the pixel circuit provides a small current by the above technical features, a longer illumination ratio can be maintained for a frame time to make the display uninterrupted, and the phenomenon of display flicker can be reduced.

