Research On Improving OLED Display Saturation And Brightness Uniformity

Compared with Liquid Crystal Display(LCD),Organic Light-Emitting Diode(OLED)has the advantages of low working voltage,fast response speed,large viewing angle,self-luminous,good flexibility,etc.,and has been widely used in Mobile devices such as mobile phones and tablets.However,there are two important problems in the display effect of OLED screens: 1.The mainstream RGBW arrangement shows low saturation,and the corresponding mapping algorithm usually aims at improving brightness without considering factors such as image color,which exacerbates the lack of saturation problem.2.The long-term,high-brightness of OLED pixels will cause the brightness to decline,making the screen display uneven brightness.The existing compensation circuit is difficult to compensate for the brightness degradation caused by various factors.For the above two problems,this paper proposes two new solutions:1.To solve the first problem,this paper proposes a new RGBWY sub-pixel arrangement method,which reduces the number of white pixels W and increases yellow pixels Y.Compared with the traditional RGBW arrangement,the influence of white pixels on surrounding pixels is reduced,and the saturation is improved.Based on the proposed new arrangement,two mapping algorithms are designed.The new algorithm introduces the concept of saturation,which can adjust the size of the white and yellow components by changing the saturation.Compared with the traditional mapping algorithm,the new mapping algorithm(1)has a higher degree of reduction of the image,and the saturation is increased by 40%.The new mapping algorithm(2)can maintain the original image saturation while increasing the brightness.2.Aiming at the second problem,this paper proposes a brightness compensation scheme based on the readout circuit.(1)A brightness readout circuit based on Capacitive Feedback Transimpedance Amplifier(CTIA)is designed.The circuit can convert the current value flowing through the pixel into a voltage value and read it out.This article mainly completes the design of CTIA circuit,Correlated Double Sample Circuit(CDS)and output buffer(Buffer).The circuit adopts TSMC 0.18 um CMOS process and uses Cadence IC616 platform to complete the simulation.(2)Based on the readout circuit,a data processing method combining interpolation and prediction is designed.The data read out by the circuit is interpolated by an interpolation algorithm,and the current value at the next moment is predicted to achieve the purpose of shortening the compensation interval.(3)Based on the above research,a new prediction algorithm is proposed.The new algorithm increases the prediction of errors.Compared with traditional prediction algorithms,the prediction algorithm proposed in this paper can predict more nodes at the same sampling interval,thereby increasing the frequency of brightness compensation and improving the uniformity of screen brightness.