Analysis of wave aberrations and optical modeling for off-axis augmented reality display

The implementation of augmented reality (AR) in optoelectronic devices is rapidly advancing, especially in systems such as head-up displays, head-mounted displays, and overhead displays. Achieving a broad field of view with high-quality images in AR displays largely depends on sophisticated optical design. Off-axis optical configurations are often utilized to address various design and manufacturing challenges. This study assesses off-axis AR displays by analyzing optical aberrations and performance metrics through a three-step design process: first, evaluating on-axis aberrations; second, investigating off-axis aberrations at a tilt angle α; and third, optimizing and controlling those aberrations. An optical system is developed based on an optimized design with the following specifications: a wavelength of 543 nm, a design eye point at 450 mm, an LCD screen size of 60 × 50 mm, and a resolution of 580 × 480 pixels with a pixel size of 10 µm. The design employs minimal optical surfaces to effectively achieve these target parameters. The prototype system meets the engineering requirements and performance goals, attaining a modulation transfer function (MTF) of 0.4 at 10 line pairs per millimeter (lp/mm) and a root mean square (RMS) spot size of 8 µm. Additionally, the study provides a concise overview of the design, analysis of optical aberrations in both on-axis and off-axis optical system and the fabrication of the prototype, which underwent thorough tolerance analysis. This analysis included evaluations and assessments of the challenges of mounting both optical and mechanical components.