System and methods for extraction of threshold and mobility parameters in amoled displays

A method of extracting a circuit parameter from a pixel circuit including:

• a light emitting device;
• a drive device to provide a programmable drive current to the light emitting device;
• a programming input;
• and a storage device to store a programming signal;
• the method comprising:
• programming the pixel circuit;
• turning on the drive device;
• and
• extracting a parameter of the drive device by reading the voltage on the drive device while passing a predetermined current through the drive device.

A system for extracting a circuit parameter from a pixel circuit including

• a light emitting device,
• a drive device to provide a programmable drive current to the light emitting device,
• a programming input, and
• a storage device to store a programming signal,
• the system comprising:
• a controller coupled to the pixel circuit and supplying controlling input signals to the pixel circuit in a predetermined sequence to produce an output voltage value which is a function of a parameter of the pixel circuit, the sequence including
• programming the pixel circuit,
• turning on the drive device, and
• extracting a parameter of the drive device by reading the current passing through the drive device while applying a predetermined voltage to the drive device or by reading the voltage on the drive device while passing a predetermined current through the drive device.