Search

We propose augmented reality (AR) near-eye display using a holographically printed freeform mirror array. A wide depth of field AR system is implemented by the retinal projection via a small mirror array. Since we use a holographic mirror array, more advantages over a traditional physical mirror array are achieved. Due to the see-through characteristics of the holographic optical element (HOE), the array structure does not obstruct the sight of an observer. Also, the holographic printing technique for the freeform mirror array enables a wide depth of field system without using a floating lens and compensates for the astigmatism of the HOE. The detailed design method of the freeform mirror array HOE is presented. Through the retinal image simulations and the experimental results, the feasibility of the proposed method is verified. [ABSTRACT FROM AUTHOR]

A compact augmented reality (AR) combiner using Pancharatnam-Berry phase (PBP) lens and holographic optical element (HOE) is proposed. PBP lens is activated as a convex lens or a concave lens according to the polarization state of the input light wave. By using this characteristic, a thin AR eyepiece with a large numerical aperture (NA) is constructed. The AR eyepiece operates as a convex lens for the input light with a right-handed circular polarization state and operates as a transparent plate for the left-handed circularly polarized light. In order to adopt this AR eyepiece to the AR combiner, a chromatic aberration should be compensated. To resolve the chromatic aberration, HOE which diffracts the light rays with different profiles according to the input wavelength is designed. By combining this HOE with the AR eyepiece and a light guide, a compact AR combiner providing a wide field of view (FOV) is designed. A prototype of the proposed AR combiner is presented along with experimental results and analysis. [ABSTRACT FROM AUTHOR]

The development of a technology acceptance model, to evaluate the causality and playfulness of Web-based negotiation support systems, is described. The usage of this model to develop a negotiation support system called CAKES-NEGO is discussed.

The electrically tunable beam deflector have been researched and developed for lots of purpose. For the transmission type beam deflector, an indium‐tin‐oxide (ITO) has been developed with blazed grating patterns. The ITO layer was designed and generated on the lower substrate for transmission type beam deflector. A pixel pitch of ITO grating patterns is 6um, the electrode width is 3um with 3um spacing. With this small pixel pitch, the maximum diffraction angle is 2.541° at a wavelength of 532nm. A minimum cell gap is 2.5um for the enough 2π phase modulation with high birefringence liquid crystal which is delta n, 0.31. Total 720‐ ITO line which was patterned on the lower substrate is controlled individually by driving integrated circuit (IC) from driving module. Beam deflector driving module with driving IC is designed for continuous beam steering. Driving algorithm is developed and applied to the driving system for high angular resolution and continuous beam steering. [ABSTRACT FROM AUTHOR]

The new encoding methods are proposed and demonstrated for amplitude‐only computer‐generated hologram (CGH). Traditionally, the amplitude‐only encoding method proposed by Burch, has been used over 50 years, because it is the deterministic solution for generating an ideal hologram added by its conjugated hologram. Since the amplitude‐only hologram cannot represent negative values, the result of Burch's encoding should always be added by some values, so that none of data is less than zero. It means that the electric‐field of zero amplitude mapped into the medium gray level in a spatial light modulator (SLM). In ideal holographic display, it does not cause any problem on reconstructing holograms, but the medium gray level actually adds the noise at the practical holographic display. We introduce the encoding methods which can map the zero amplitude into the zero gray level. These encoding methods can increase the contrast ratio of an amplitude‐only hologram by reducing unnecessary scattering and stray lights. [ABSTRACT FROM AUTHOR]

A projection-type layered display inducing the accommodation cue is proposed. To support the accommodation cue, the concept of multiplane displays, especially the principle of additive type compressive light field display, is adopted. To achieve the additive type light field display, two layered scattering polarizers and a single projector which is synchronized with polarization rotator are used. Scattering polarizer diffuses light rays with specific linear polarization state while transmits the other rays with the orthogonal polarization state. Utilizing this characteristic, two layer images can be displayed at different depths presenting multiplane display. By adopting an additional computational process, several viewpoints can be provided to a single eye and support the accommodation cue. We expect that the proposed method can be adopted to virtual reality system. Detailed principle of the proposed system and its feasibility are explained with simulations and experiments. [ABSTRACT FROM PUBLISHER]

Multi-projection three-dimensional (3D) display system with dual projection using uniaxial crystal is proposed. The dual projection means that multiple images are generated by double refraction in the uniaxial crystal according to the polarization state of a single projection unit. The concept of dual projection method is equivalent to physically separated two projectors. We apply the dual projection method in the multi-projection 3D display and double the number of viewing zones while maintaining the number of projectors. Through the experiment, we implement the four-view multi-projection 3D display providing super multi-view condition with two projection units. Experimental results verify the feasibility of the proposed system. [ABSTRACT FROM AUTHOR]

Abstract: Background: Recent technical developments with high-resolution real-time 3 dimensional echocardiography (RT3DE) facilitate the acquisition of high quality images and the analysis of segmental volume–time curves (VTCs). Aims: To assess left ventricular (LV) asynchrony using the VTCs of 16 segments by RT3DE, and to evaluate accuracy compared to tissue Doppler imaging (TDI). Methods: Twenty-three heart failure (HF) patients (LVEF: 25±6%, age: 60±13 years) and 16 normal controls underwent TDI and RT3DE. The standard deviation (SD3) of the end systolic time reaching minimal systolic volume for the 16 segments on VTCs was obtained by RT3DE. The standard deviation (SD2) of the electromechanical coupling time for the 8 segments was measured using TDI. Results: SD3 was markedly higher in HF patients than in controls (7.7±2.5 vs 1.5±1.0%, P <0.01) and increased as LVEF decreased (r =−0.85, P <0.01). SD2 was also significantly higher in HF patients (27.0±8.6 vs 12.6±5.0 ms, P <0.01) and had a good negative correlation with LVEF (r =−0.72, P <0.01). SD3 was well correlated to SD2 (r =0.66, P <0.01). Conclusions: We suggest that analysis of VTCs in 16 segments using RT3DE may be a useful alternative to TDI for the evaluation of LV asynchrony. [Copyright &y& Elsevier]

Metasurface‐based flat optics has a great potential to replace conventional bulky and heavy optical elements, consistent with the trend of miniaturizing optical elements. One of the trends is to broaden the operating area of the metasurface. The previous approaches are focused on expanding the metasurface area, which has intrinsic manufacturing and optical limitations. Here, this work presents the fabrication of wafer‐scale metalens arrays, and demonstrates the Gabor superlens composed of the metalens arrays, which behaves optically like a large lens system. A pair of fabricated 8‐inch‐sized metalens arrays are used to float the large‐area display, producing a real image in the air. This superlens is easily manufactured in a high‐throughput and cost‐effective manner using an argon fluoride dry scanner and a single reticle. Their capability for diffraction‐limited focusing and imaging is demonstrated. Considering the groundbreaking nature of imaging a large‐area display through the metalens arrays, this work shows a great potential for scaling up the optical display systems in a simple manner. [ABSTRACT FROM AUTHOR]

Isotopic analyses of ground waters collected from 1966 through 1968 on Cheju Island, Republic of Korea, have proved helpful in interpreting the general hydrologic relations and in developing a model of the ground-water flow system in the permeable volcanic rocks of the island. Comparison of tritium and stable isotope (D-18O) contents provided a basis for a model of the ground-water flow regimes. Time variability of these isotopes determined by repeated samplings provided the basis for estimates of mean residence time of ground waters, ranging from about 2 to 9 years. Although the results are only approximate because simplified models were used, they can be of substantial assistance in planning further hydrologic investigations and appraising the feasibility of ground-water development. [ABSTRACT FROM AUTHOR]