Chen Yi-Jiun, Lee Wei-Kai, Chen Yi-Ting, Lin Chun-Yu, Wen Sheng-Wen, Jiao Min, Su Guo-Dong, Lin Hoang Yan, Visser Robert J, Kwak Byungsung Leo, Chen Chung-Chia, Lin Wan-Yu, Wang Steve, Chang Chorng-Ping, Wu Chung-Chih
Graduate Institute of Photonics and Optoelectronics Graduate Institute of Electronics Engineering Department of Electrical Engineering National Taiwan University Taipei 106 Taiwan.
Applied Materials, Inc. Santa Clara, CA 95052 USA.
Adv Sci (Weinh). 2018 Aug 29;5(10):1800467. doi: 10.1002/advs.201800467. eCollection 2018 Oct.
Despite stringent power consumption requirements in many applications, over years organic light-emitting diode (OLED) displays still suffer unsatisfactory energy efficiency due to poor light extraction. Approaches have been reported for OLED light out-coupling, but they in general are not applicable for OLED displays due to difficulties in display image quality and fabrication complexity and compatibility. Thus to date, an effective and feasible light extraction technique that can boost efficiencies and yet keep image quality is still lacking and remains a great challenge. Here, a highly effective and scalable extraction-enhancing OLED display pixel structure is proposed based on embedding the OLED inside a three-dimensional reflective concave structure covered with a patterned high-index filler. It can couple as much internal emission as possible into the filler region and then redirect otherwise confined light for out-coupling. Comprehensive multi-scale optical simulation validates that ultimately high light extraction efficiency approaching ≈80% and excellent viewing characteristics are simultaneously achievable with optimized structures using highly transparent top electrodes. This scheme is scalable and wavelength insensitive, and generally applicable to all red, green, and blue pixels in high-resolution full-color displays. Results of this work are believed to shed light on the development of future generations of advanced OLED displays.
尽管在许多应用中对功耗有严格要求，但多年来，由于光提取效率低下，有机发光二极管（OLED）显示器的能源效率仍不尽人意。已有报道称有一些方法可用于OLED的光出耦合，但由于显示图像质量、制造复杂性和兼容性等方面的困难，这些方法通常不适用于OLED显示器。因此，迄今为止，仍然缺乏一种既能提高效率又能保持图像质量的有效且可行的光提取技术，这仍然是一个巨大的挑战。在此，基于将OLED嵌入覆盖有图案化高折射率填充材料的三维反射凹面结构中，提出了一种高效且可扩展的增强提取效率的OLED显示像素结构。它可以将尽可能多的内部发射光耦合到填充材料区域，然后将原本受限的光重新定向以进行出耦合。全面的多尺度光学模拟验证了，使用高度透明的顶部电极并通过优化结构，最终可以同时实现接近80%的高光提取效率和出色的观看特性。该方案具有可扩展性且对波长不敏感，并且通常适用于高分辨率全彩显示器中的所有红色、绿色和蓝色像素。相信这项工作的结果将为下一代先进OLED显示器的发展提供启示。
