LED near-eye holographic display with a large non-paraxial hologram generation

Abstract

In this paper, two solutions are proposed to improve the quality of a large image that is reconstructed in front of the observer in a near-eye holographic display. One of the proposed techniques, to the best of our knowledge, is the first wide-angle solution that successfully uses a non-coherent LED source. It is shown that the resulting image when employing these types of sources has less speckle noise but a resolution comparable to that obtained with coherent light. These results are explained by the developed theory, which also shows that the coherence effect is angle varying. Furthermore, for the used pupil forming display architecture, it is necessary to compute a large virtual nonparaxial hologram. We demonstrate that for this hologram there exists a small support region that has a frequency range capable of encoding information generated by a single point of the object. This small support region is beneficial since it enables to propose a wide-angle rigorous CGH computational method, which allows processing very dense cloud of points that represents three-dimensional objects. This is our second proposed key development. To determine the corresponding support region, the concept of local wavefront spatial curvature is introduced, which is proportional to the tangent line to the local spatial frequency of the spherical wavefront. The proposed analytical solution shows that the size of this area strongly depends on the transverse and longitudinal coordinate of the corresponding object point.

Research Progress of Large Viewing‐Area 3D Holographic Near‐Eye Display

“…[ [74] ] to expand the eyebox, and a larger transversal movement would be allowed. Moreover, for the passive steering viewing window techniques, in addition to the steering system, accurate encoding algorithms were also required to provide the correct view in the areas outside the central part of the eyebox replicas.…”

“…Moreover, for the passive steering viewing window techniques, in addition to the steering system, accurate encoding algorithms were also required to provide the correct view in the areas outside the central part of the eyebox replicas. [74,47] Finally, the parameters and results of the above-mentioned holographic near-eye display systems based on the steering viewing window are all summarized in Table 2. Although the current implementation results achieved so far have not met expectations, the steering viewing window techniques based on eye tracking show great potential in holographic near-eye displays.…”

“…[ 73 ] Similarly, a diffraction grating generating higher‐order diffraction terms was employed in Ref. [ [ 74 ] ] to expand the eyebox, and a larger transversal movement would be allowed. Moreover, for the passive steering viewing window techniques, in addition to the steering system, accurate encoding algorithms were also required to provide the correct view in the areas outside the central part of the eyebox replicas.…”

Nano-structuration influence on the polyimide-based spatial light modulator’s parameters

“…Moreover, the specific organic molecular crystal and classical ones were presented [16,18,26] to use them in the modulation technique area. Furthermore, novel interesting architecture of the LC structures and features of the schemes are considered [20,[31][32][33][34][35] . It should be remembered that basically three famous schemes can be used in order to operate with the SLM structure and to predict the unique properties.…”

“…The effective operation of the LC-SLM is connected with some geometric (constructions, scheme to activate the devices by the external fields) and with the physical-chemical parameters, which regarded not only to the specific native parameters of the modulators, but also depended on the modifications, for example, via nano-structuring of the interface, photo layer or modulating compound [9,13,[28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] . So, it should be clarified why the study of the parameters of the classical or modified SLMs is so important?…”