Enhanced field uniformity of holographic near-eye display system based on spatial light modulator

Abstract

In this paper, a method is proposed to increase the field uniformity of holographic near-eye display system based on liquid crystal spatial light modulator (LC-SLM). The holographic near-eye display system consists of a projector, a display component and a receiver. The projector is used as an image source that based on LCOS, LCD, Micro-LED, DLP or other projection technique. The display component transmits images from the projector to the receiver, which contains at least one layer optical waveguide, in-coupling holographic grating and holographic out-coupling grating. The grating is a periodic structure formed by interference exposure on a photopolymer material. The exposure dosage determines its diffraction efficiency controlling the energy ratio of 0th-order transmitted light and 1st-order diffracted light. The average refractive index of the holographic grating is determined by the photopolymer material, and the refractive index modulation is determined by the interference exposure dosage. The higher refractive index modulation contributes to higher diffraction efficiency. The projection light diffracts into the optical waveguide through in-coupling holographic grating, and propagates to out-coupling holographic grating by total internal reflection. The out-coupling grating diffracts the light out of optical waveguide to the receiver that can be an eye or a CCD detector. The display component plays a key role in holographic near-eye display system, which directly determines the display performance (FOV, field uniformity, brightness, etc.).