Color dispersion free holographic screen based on volume holographic optical element for augmented space projection display

In this paper, a transmission-type full-color holographic screen based on VHOEs is newly proposed, and with which a new type of augmented-reality projection display is implemented. For this, a two-stage diffraction method with two kinds of VHOEs is proposed for the effective removal of color dispersion and DC component. That is, the 1st VHOE for removing color-dispersion is recorded at the angle cutting 60° in half and 2nd VHOE for displaying the full-color image is recorded at the angle of 30°. Then, a projection display system to reconstruct the full-color image without color dispersion and DC component is optimally designed and implemented just by controlling the angles of the LCD display panel and VHOEs, as well as the distance between the two VHOEs. With experiments, the image clarity depending on the focus of the eyes as a space-projection system, as well as the degree of removal of the color dispersion, has been discussed. In addition, successful experimental results confirm a possibility of implementing the VHOE-based full-color augmented-reality projection display system.