Astigmatism and deformation correction for a holographic head-mounted display with a wedge-shaped holographic waveguide.

In this study, a head-mounted display (HMD) system based on a wedge-shaped holographic waveguide that can present holographic virtual images with tunable distance is achieved. The compact computer-generated-hologram system using a spatial light modulator was employed to offer the dynamic image, where the probe beam for the hologram reconstruction is a convergent wave, and the DC term of the diffraction wave can be blocked by a barrier. The wedge-shaped holographic waveguide element was used as the combiner of the HMD system to generate a compact structure. A wedge with a polished surface was designed for in-coupling the image into the waveguide, and a reflection-type holographic optical element (HOE) was used for out-coupling the image from the waveguide. The astigmatism aberration and deformation of the diffraction images at various distances are analyzed and then are compensated. Finally, the virtual image can be obtained without aberration with experimental verification.