Miniaturization design of head-mounted display optical system based on double threshold method for virtual reality

Abstract To increase the sense of three-dimensional immersion and comfort, a head-mounted display (HMD) system used for virtual reality (VR) should achieve an excellent optical performance and a compact structure. In general, a Fresnel lens is applied to decrease the dimensions and weight of the monocular optics. However, the amount of decrease is limited when utilizing a Fresnel lens alone. To further improve the compactness of an HMD optical system, a double threshold method based on the Delano theory and a genetic algorithm is proposed. The first-order structure gained using this method is suitable for the design of a miniaturized HMD optical system. To verify its feasibility, a three-piece optical system utilizing PMMA and PC was designed. The results indicate that the total length of the optical system is approximately 55 mm and the weight of the monocular optics is approximately 5.6 g without a decrease in the optical performance. The reductions in the dimensions and weight are obvious.