Optical design of a wide-angle pinhole lens for VR and AR inspection

Virtual reality (VR) and augmented reality (AR) have widespread applications in education, military, medical treatment, and entertainment. The key parameters of near-eye displays, such as field of view (FOV), eye box size, resolution, and virtual image distance will critically influence the performance of the final display products. Meanwhile, VR and AR displays are designed to achieve a very wide FOV to improve the immersive visual experience recently. Especially in VR applications, the FOV has been more than 90° to blur the boundary between the virtual and real world. Thus, a wide-angle forward-stop anthropomorphic vision lens for VR and AR inspection should be studied. However, it is very challenging to achieve wide FOV and high resolution simultaneously in a compact pinhole lens. In this study, a pinhole lens using an advanced photo system-classic (APS-C) size sensor with a FOV of 110° and an entrance pupil diameter (EPD) of 4 mm is designed. The optimization process is introduced, and the optical performance is analyzed. In our design, optical aberration is well corrected to improve the image quality. The cut-off spatial frequency of the modulation transfer function (MTF) across the whole field is 200 cycles/mm. The MTF is greater than 0.43 at the Nyquist frequency (NF), the field curvature is controlled within 0.04 mm, and the distortion of the system is less than 10% across the 0.82 field. The overall length (OAL) of the system is less than 230 mm. The result shows that our pinhole lens is a high-resolution wide-angle optical system and meets the requirements for VR and AR inspection.