PWM(PULSE WIDTH MODULATION) PRE CHARGE OF ORGANIC LIGHT EMITTING DIODES FOR DISCHARGING ANODES TO BELOW THE INTENSITY LEVEL OF AN OLED(ORGANIC LIGHT EMITTING DIODE) PIXEL

摘要

PURPOSE: The PWM(Pulse Width Modulation) pre charge of organic light emitting diodes is provided to improve the image quality of OLED(Organic Light Emitting Diode) displays by including light which is generated for a pre-charge step at a whole light budget.;CONSTITUTION: An addressed pixel becomes pre-charged to a light emitted critical value(32). A critical value is determined to change the pre-charge of a pixel into a driving stage for the number of a PWM(Pulse Width Modulation) which is used to pre-charge(33). The pixel becomes pre-charged to a required forward voltage or a desired PWM number if being firstly pre-charged(34). Light, which is generated during pre-charge, is added to the desired light budget of the pixel(35). The pixel is driven with a current until being arrived to the whole light budget of the pixel including the light which is generated during pre-charge(36). The pixel is discharged to below the light emitting critical value(37).;COPYRIGHT KIPO 2012