The turn‐on characteristics of a green two‐stack tandem organic light‐emitting diodes (OLED) driven by square‐wave pulses were investigated, revealing a pronounced luminance overshoot which was found to depend strongly on the driving voltage, confirming its origin in the charge generation layer (CGL). A physical model based on charge storage and release from the diffusion capacitance of the CGL's internal PN junction successfully explained the observed behavior.
We report novel host materials for n‐type charge generation layers (nCGLs). These hosts are not based on phenanthroline and enable blue tandem OLEDs to achieve lower operating voltage and longer lifetime than conventional phenanthroline‐derived nCGL hosts. In electron‐only devices, the current density was reduced by up to two orders of magnitude, suggesting a practical approach to suppressing pixel‐to‐pixel lateral leakage in highresolution OLED displays.
On FALD displays, the luminance of a moving white object fluctuates as it moves across the screen and users can perceive it as flicker. Since flicker is associated with health issues, this phenomenon needs to be defined and quantified as an important local dimming artifact. We identified this flicker phenomenon in dynamic content as “dimming flicker”. Using a high‐speed camera and a photometer, we have found that dimming flicker is a noticeable artifact in dynamic content. Based on analysis of its primary cause, we proposed the measurement method to quantify dimming flicker. Through two subjective experiments, we demonstrated that the proposed measurement and index can explain users’ dimming flicker experiences.
With the increasing demand for high‐definition display quality in low‐brightness scenes, the brightness resolution and color accuracy of organic light‐emitting diode (OLED) displays under low‐brightness and low‐gray‐scale conditions have become key performance indicators. Current experimental samples generally suffer from difficulties in single‐color expansion, uneven gray‐scale transitions, crosstalk between adjacent color cells, and Gaussian blurring, among other abnormal phenomena. The core cause lies in the delay problem of turning on at extremely low brightness levels. The pre‐/delay of turning on the gray‐scale determines the screen's ability to restore dark field details and directly affects the image contrast and depth. This paper systematically reviews the key influencing factors of turning on the gray‐scale, proposes a new leakage current characterization method, and constructs a non‐linear collaborative optimization scheme for leakage current and brightness. Firstly, by adjusting the plasma treatment (PT) processing parameters of the ITO anode (N₂: O₂ ratio), the surface energy of the anode and the carrier injection barrier are optimized, reducing the pixel leakage current by an order of magnitude. Secondly, a non‐linear 1‐gray‐scale Gamma assignment algorithm is proposed to compensate for the non‐linear attenuation of the driving current at low gray‐scales, ensuring the accuracy of low‐gray‐scale rendering and the uniformity of picture transitions while meeting the requirements of ultra‐high‐definition display for low‐gray‐scale dynamic performance.
To improve the resolution of coarse integral image (CII) display, the use of a fine interleaved Fresnel lens array has been proposed. However, the background of the aerial image obtained by conventional methods is monochromatic and lacks a sense of reality. We propose a method for displaying a background image occluded by an aerial image, using a time‐division technique that switches between two display states.
