Design and optimization of a collimating lens for ultra-small µ LED displays using FDTD simulation

作者：Shuming Zhang, Shulin Chen, Liang Zhang, Runan Zhang, Yujia Gong, Jiahao Kang, Cheng‐Zhe Chai, Lei Zhao, Chaohao Wang, Yuan Ze · 发表于：Optics Express · 年份：2024 · DOI：10.1364/oe.546355 · 被引用次数：7 · 研究领域：Semiconductor Lasers and Optical Devices、Optical Systems and Laser Technology、Advanced Optical Imaging Technologies

Next-generation augmented reality (AR) displays offer immersive three-dimensional visual experiences, demanding advanced technologies to meet stringent visual requirements. Micro-LED ( µ LED) technology has emerged as a promising option for AR displays, owing to its high brightness, small pixel size, and low power consumption. Efficient extraction and collimation of the light generated by µ LED panels remains a major challenge, primarily because of the large divergence angle caused by strong sidewall emission. To address this issue, we propose a freeform lens that effectively collimates the light emitted from ultra-small µ LED pixels, potentially enhancing the overall performance of the display. The lens is designed and optimized using finite-difference time-domain (FDTD) simulations. Our study focuses on the impact of dipole source positions on the collimation efficiency and demonstrates how increasing the distance between the lens surface and the µ LED panel reduces the sensitivity to dipole positions, owing to the spatial filtering effect. The proposed lens design achieves a significant increase in collimated light intensity–approximately 58 times–within a ±10° range compared to µ LEDs without any collimating structure. These findings provide valuable insights and guidance for designing efficient collimating lenses tailored to the stringent requirements of ultra-small µ LED displays in AR applications.