Hybrid refractive/diffractive eyepiece for head-mounted display with multilayer diffractive optical element

Based on the theory analysis of diffraction efficiency of multilayer diffractive optical element (MDOE), a hybrid diffractive-refractive eyepiece for head-mounted display (HMD) with MDOE was designed. The diffraction efficiency of the system at each field of view (FOV) and in design wave band was lager than 90%, which improved the utilization rate of energy and contrast ratio of image. The exit pupil distance and diameter of 60 FOV eyepiece were 22 mm and 8 mm. The distortion was less than 4.8 % and the maximum lateral color difference was 10 m. The modulation transfer function (MTF) value was more than 0.38 for all FOV at spatial frequency 25 lp/mm. It met the requirement of VGA resolution. The structure of the total system is compact, the length of lens is 26.8 mm, the maximum diameter is 16 mm, and the weight of the entire system is only 8 g. It realizes the miniaturization optical system.