Abstract: Compensation needed to be made for reduced light efficiency in aged sub-pixels of an active matrix organic light-emitting diode (OLED) display are determined using a current ratio or a voltage ratio pertaining to an aged sub-pixel relative to un-aged, reference sub-pixels. When the current through the sub-pixels or the voltage across the sub-pixels are measured to determine the age of the sub-pixels, correction is made to the measured current or voltage to account for variations in the ambient temperature in which the OLED display is placed.

Abstract: A plurality of gray level versus OLED current curves are generated by measuring many OLED panels from a stable manufacturing process, and those curves are stored as standard gray level versus OLED current curves. When a new OLED display is manufactured from the process, each of its sub-pixels is characterized as having the characteristics of one of the pre-generated standard gray level versus OLED current curves, based on a gray level versus OLED current measurement at a single gray level. This drastically reduces the time it takes to determine the TFT gate voltage versus OLED current characteristics of the sub-pixels in the OLED display. The OLED display can use the selected one of the pre-generated standard gray level versus OLED current curves to correct non-uniformities of the sub-pixels in the OLED display caused by non-uniform TFTs in the active matrix.