Multi-SLM Color Holographic 3D Display Based on RGB Spatial Filter

A novel approach for color holographic 3D displays employing several liquid crystal based spatial light modulators (SLM) is presented. A multicolor reconstruction is introduced into circular monochrome display architecture with horizontal-only-parallax through the use of space-division method (SDM). In the SDM active area of an SLM is divided into three regions generating the RGB component images by using color spatial filter composed of a three glass stripes that are attached to the front of each SLM. Relatively low complexity level of SDM enables to upgrade a horizontal-only-parallax monochrome display to a color one at the expense of image resolution. There is no reduction of remaining key performance parameters, i.e., image dimensions, refresh frame rate, and viewing angle are preserved with no increase of SLM number. In this paper, practical aspects of color imaging implementation, including filter mask design and hardware calibration, are considered. Developed procedures focus on major three effects, i.e., spectral calibration of response of highly dispersive SLM phase, spatial calibration of filter mask and numerical alignment of RGB imaging volumes. The presented experimental results of static and dynamic 3D reconstructions of computer generated holograms validate the performance of calibration procedures and the high color imaging quality of the display.