A Research On White Balance For Full Color AMOLED

Organic light emitting display(OLED) have attracted much attention and rapiddevelopment in recent years because of its excellent characteristics，such as colorful,self-light emitting and can be used for flexible displays. To reflect the advantages of OLEDcolor image, it is necessary to achieve the white balance of the image.This paper discusses the white point of reference for the selection reasons. We analysisthe RGB pixel independent luminescence method features, compares the different methodsof the size of the color gamut, and compares the color gamut of the OLED screen used inthis paper with of the TV. The manual Settings D65and D93for reference white point andautomatic white balance adjustment in parallel mode, make OLED displays can not onlyshow a reference white point set image, but also accurate show the image in other lightsources according to the image information. So that the OLED displays have a wider rangeof display area.Because single use digital method can lead to grey level is reduced, and single use aanalog method to realize the trimming or circuit is too complex, this paper adopted digitalanalog of the method of combining realized AM-OLED white balance, make up for thedeficiency of them. First we determine the driving voltage according to the tricolor relativebrightness ratio to complete the analog adjusting, then start to digital adjusting. Try themethod of least squares, steepest descent BP algorithm, it is found that this two algorithmsare failed to complete the fitting of transfer character curve, and eventually adopted L-M(Levenbery-Marquardt) optimized BP (back-propagation) neural network algorithm to fitthe OLED transfer character curve. Compared to traditional BP algorithms, this algorithmis more suitable for fitting monotonic increase transfer character curve, it can fastconvergence, and ensure the monotonic of curve. The simulation result shows that thismethod can achieve the white balance of the image.Finally, analysis of the three primary colors degradation unbalanced dialogue balanceinfluence, and use the linear compensation method, makes the image still can realize whitebalance.