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We analyze an image quality of a holographic lens (HL) in order to implement compact near-eye displays using a flat-panel-type micro-display panel. The proposed method utilizes a non-converging signal wave in a fabrication process of the HL, so that it provides affordable eye-box size with minimizing the aberration due to rays in the off-Bragg condition. For analyzing and optimizing the HL based on the non-converging signal wave, we introduce a comprehensive analysis model for an assessment of the image quality in the HL. The analysis model, inspired from the conventional lens design strategy for near-eye displays, evaluates the focal spot quality for incident rays forming each pixel with considering the on- and off-Bragg diffraction. The theoretical analysis is validated by simulation results using a volume hologram model in Zemax OpticStudio. As experimental verifications, we realize a prototype system using photopolymer-based HLs in a green color with the high transmittance of 89.3%. The image quality of the HLs is analyzed, which coincides well with the proposed analysis and assessment metric. By building a compact experimental setup employing the HL and a micro-organic light emitting diode display, we present see-through images with 8.0 mm of eye-box with reduced aberrations.

Two novel methods are proposed which enhance the angular sampling rate of the integral floating display by adopting dynamically variable apertures in front of the lenslet array or the floating lens. Adopted dynamically variable apertures are opened sequentially in synchronization with proper elemental images to subdivide the angular sampling step by time-multiplexing method. Our proposed method can enhance the angular sampling rate, which is related to an expressible longitudinal range, without sacrificing other visual quality factors in tradeoff relationship. Especially, our proposed method with apertures on the floating lens provides two-dimensional/three-dimensional convertible feature to integral floating display system., (© 2012 Optical Society of America)

We propose a new method for rectifying a geometrical distortion in the elemental image set and extracting an accurate lens lattice lines by projective image transformation. The information of distortion in the acquired elemental image set is found by Hough transform algorithm. With this initial information of distortions, the acquired elemental image set is rectified automatically without the prior knowledge on the characteristics of pickup system by stratified image transformation procedure. Computer-generated elemental image sets with distortion on purpose are used for verifying the proposed rectification method. Experimentally-captured elemental image sets are optically reconstructed before and after the rectification by the proposed method. The experimental results support the validity of the proposed method with high accuracy of image rectification and lattice extraction.

This paper presents design and implementation of a color wavefront holographic printer. The printer output is a white light viewable volume hologram composed as a two-dimensional (2-D) array of elemental holograms. The three-dimensional (3-D) input data for the printer are encoded as computer generated holograms (CGHs) displayed in succession on an amplitude type spatial light modulator. The printer optical head extracts and demagnifies the beam with the 3-D object information from the beam diffracted by the modulator to produce a small size elemental hologram. This allows for mosaic delivery of exposures at primary colors with each elemental hologram acting as a single color channel. Computer generation of digital contents is accelerated by design of a phase-added stereogram approach based on partitioning of each CGH. Bright 3-D reconstruction with a motion parallax at saturated colors from holograms of test objects is presented. The holograms are printed on a silver-halide emulsion. The achieved high quality proves feasibility of recording analog color volume holograms from digital contents by mosaic delivery of the primary colors. Two quality enhancement approaches are proposed and tested. [ABSTRACT FROM PUBLISHER]