Research On Near-eye Display System Based On Metasurface

As the main product in future wearable devices,near-eye display system(NED)is one of the key research directions in the field of electronic devices in recent years.The application of such a head-mounted display device is very extensive.It can bring great benefits to people in military exercises,industrial production,education,teaching,entertainment and so on.The virtual reality near-eye display system can bring strong immersion to the user,while the augmented reality near-eye display system superimposes the display information in the real environment.Both of them put forward high requirements for the lightweight and miniaturization of the NED device.Metasurface is a kind of man-made structure which can accurately and flexibly control the phase,amplitude,polarization of electromagnetic wave by judiciously engineering subwavelength scale microstructure array on a flat plane.It can achieve some functions that are difficult to achieved with traditional geometric optics.It can use only one surface of the sub-wavelength thickness to achieve the same function as one or several conventional optical component groups.Metasurface providing a new solution for reducing the size of optical devices.In this paper,a small-weight,lightweight,augmented reality color near-eye display system is proposed which combines the metasurface with the near-eye display system.The system has a very simple structure that consists of only one ultra-microstructure surface and one micro-display.The appearance is close to ordinary glasses and has the potential to be extended to integrate with myopia glasses.The fully dielectric semi-transparent metasurface is placed only 15 mm from the eye where close to the position of ordinary glasses.Besides,the user can clearly present the image on the retina while the change of the focal length of the eye,based on the structural design of the retinal display technology.Zemax is used to simulate the geometrical optics of the whole system.The effect of the metasurface is replaced by the set of surface characteristics.The image distortion received by the eye under ideal conditions is only 0.0004%,which achieves very good imaging results.Then,design the real microstructure array on the metasurface and use COMSOL to explore the properties of the basic elements of the g eometric phase-type ultrastructure surface under oblique incidence.The FDTD method is used to simulate the system composed of the real microstructure metasurface not just numerical property.And the pattern composed of multiple monochromatic Gaussian sources can be reproduced well in the eye.The system is extended to colorful display by superposition of red,green and blue light,which can reproduce the color image well.