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The super multi-view (SMV) near-eye display (NED) effectively provides depth cues for three-dimensional (3D) displays by projecting multiple viewpoint images or parallax images onto the retina simultaneously. Previous SMV NED suffers from a limited depth of field (DOF) due to the fixed image plane. Aperture filtering is widely used to enhance the DOF; however, an invariably sized aperture may have opposite effects on objects with different reconstruction depths. In this paper, a holographic SMV display based on the variable filter aperture is proposed to enhance the DOF. In parallax image acquisition, multiple groups of parallax images, each group recording a part of the 3D scene on a fixed depth range, are captured first. In the hologram calculation, each group of wavefronts at the image recording plane (IRP) is calculated by multiplying the parallax images with the corresponding spherical wave phase. Then, they are propagated to the pupil plane and multiplied by the corresponding aperture filter function. The size of the filter aperture is variable which is determined by the depth of the object. Finally, the complex amplitudes at the pupil plane are back-propagated to the holographic plane and added together to form the DOF-enhanced hologram. Simulation and experimental results verify the proposed method could improve the DOF of holographic SMV display, which will contribute to the application of 3D NED.

Over the last decade, Optical Phased Arrays (OPA) have been extensively studied, targeting applications such as Light Detection And Ranging (LiDAR) systems, holographic displays, atmospheric monitoring and free space communications. Leveraging the maturity of the silicon photonics platform, the usual mechanical based beam steering system could be replaced by an integrated OPA; significantly reducing the cost and size of the LiDAR while improving its performance (scanning speed, power efficiency, resolution…) thanks to solid state beam steering. However, the realization of an OPA that meets the specifications of a LiDAR system (low divergence and single output beam) is not trivial. Targeting the realization of a complete LiDAR system, the technical challenges inherent to the development of high performance OPAs have been studied at CEA LETI. In particular, efficient genetic algorithms have been developed for the calibration of high channel count OPAs as well as an advanced measurement setup compatible with wafer-scale OPA characterization.

Cataract is a common ophthalmic disease in which a cloudy area is formed in the lens of the eye and requires surgical removal and replacement of eye lens. Careful selection of the intraocular lens (IOL) is critical for the post-surgery satisfaction of the patient. Although there are various types of IOLs in the market with different properties, it is challenging for the patient to imagine how they will perceive the world after the surgery. We propose a novel holographic vision simulator which utilizes non-cataractous regions on eye lens to allow the cataract patients to experience post-operative visual acuity before surgery. Computer generated holography display technology enables to shape and street the light beam through the relatively clear areas of the patient's lens. Another challenge for cataract surgeries is to match the right patient with the right IOL. To evaluate various IOLs, we developed an artificial human eye composed of a scleral lens, a glass retina, an iris, and a replaceable IOL holder. Next, we tested different IOLs (monofocal and multifocal) by capturing real-world scenes to demonstrate visual artifacts. Then, the artificial eye was implemented in the benchtop holographic simulator to evaluate various IOLs using different light sources and holographic contents., 6 pages, 6 figures, conference poster manuscript

In this paper, we propose a method to generate multi-depth phase-only holograms using stochastic gradient descent (SGD) algorithm with weighted complex loss function and masked multi-layer diffraction. The 3D scene can be represented by a combination of layers in different depths. In the wave propagation procedure of multiple layers in different depths, the complex amplitude of layers in different depths will gradually diffuse and produce occlusion at another layer. To solve this occlusion problem, a mask is used in the process of layers diffracting. Whether it is forward wave propagation or backward wave propagation of layers, the mask can reduce the occlusion problem between different layers. Otherwise, weighted complex loss function is implemented in the gradient descent optimization process, which analyzes the real part, the imaginary part, and the amplitude part of the focus region between the reconstructed images of the hologram and the target images. The weight parameter is used to adjust the ratio of the amplitude loss of the focus region in the whole loss function. The weight amplitude loss part in weighted complex loss function can decrease the interference of the focus region from the defocus region. The simulations and experiments have validated the effectiveness of the proposed method.

A digital micromirror device (DMD) has a wide range of applications in holographic display, light field manipulation, etc., due to its high-speed refresh rates. In order to precisely control the wavefront, the influence of the micromirror array structure of the DMD requires careful analysis. Based on an accurate three-dimensional phase model of DMD, we analyzed the diffraction characteristics of DMD. The model was established by accurately describing the phase distribution along each micromirror surface direction, and the distance between the point on the micromirror and the diffraction plane. The results showed that the orders of the DMD are the results of two groups of micromirrors interfering with each other, and a slight offset occurs when the incidence angle is twice the micromirror tilt angle, which can be removed by adjusting the incidence angle. The phase distribution results showed the main order of the DMD with all micromirrors in the on state can be approximated as a plane wave, which means that the hologram can be normally loaded on the DMD without worrying about phase disturbance from the micromirror array structure. This provides great convenience for computer holography based on DMD. Numerical simulations and experiments demonstrated the effectiveness of the work.

Limited by the low space-bandwidth product of the spatial light modulator (SLM), it is difficult to realize multiview holographic three-dimensional (3D) display. To conquer the problem, a method based on the holographic optical element (HOE), which is regarded as a controlled light element, is proposed in the study. The SLM is employed to upload the synthetic phase-only hologram generated by the angular spectrum diffraction theory. Digital grating is introduced in the generation process of the hologram to achieve the splicing of the reconstructions and adjust the position of the reconstructions. The HOE fabricated by the computer-generated hologram printing can redirect the reconstructed images of multiview into multiple viewing zones. Thus, the modulation function of the HOE should be well-designed to avoid crosstalk between perspectives. The experimental results show that the proposed system can achieve multiview holographic augmented reality (AR) 3D display without crosstalk. The resolution of each perspective is 4K, which is higher than that of the existing multiview 3D display system.

Computer-generated holographic (CGH) displays show great potential and are emerging as the next-generation displays for augmented and virtual reality, and automotive heads-up displays. One of the critical problems harming the wide adoption of such displays is the presence of speckle noise inherent to holography, that compromises its quality by introducing perceptible artifacts. Although speckle noise suppression has been an active research area, the previous works have not considered the perceptual characteristics of the Human Visual System (HVS), which receives the final displayed imagery. However, it is well studied that the sensitivity of the HVS is not uniform across the visual field, which has led to gaze-contingent rendering schemes for maximizing the perceptual quality in various computer-generated imagery. Inspired by this, we present the first method that reduces the "perceived speckle noise" by integrating foveal and peripheral vision characteristics of the HVS, along with the retinal point spread function, into the phase hologram computation. Specifically, we introduce the anatomical and statistical retinal receptor distribution into our computational hologram optimization, which places a higher priority on reducing the perceived foveal speckle noise while being adaptable to any individual's optical aberration on the retina. Our method demonstrates superior perceptual quality on our emulated holographic display. Our evaluations with objective measurements and subjective studies demonstrate a significant reduction of the human perceived noise.

In a classical metasurface-based holographic display system, a clear holographic reconstruction image can be obtained only in the back-focal-plane of the lens. However, when the receiving plane deviates from the focal plane, the reconstructed holographic image suffers from degradations that limit the quality of the images. Hence, we propose a novel metasurface-based holographic display to realize clearly continuous imaging within the specified position range by superimposing the meta-axilens phase. It can effectively relieve the alignment requirements of the imaging system. Firstly, the parameters and properties of all-dielectric meta-atom is analyzed. Then we compare and demonstrate two sets of metasurface-based optical elements (meta-axicon, meta-lens, and meta-axilens), made by silicon meta-atoms working at 610 nm. Furthermore, we show that the metasurface hologram with the axilens phase can form a series of the relatively clear holographic images away from the focal plane. Our proposal suggests a method to reconstruct holographic wavefront in different planes simultaneously, and one can find their application domain, such as 3D biological imaging, spectroscopy, optical information storage, and encryption.

Holographic display requires thinner liquid crystal cell for smaller pixels and fast response. In this paper, a continuous geometric phase modulation method realised by electrically tuning a dual i...

Human anatomy is a biology field that studies human body which consists of intricate and complex piece of engineering in which every assembly has an important role. This subject is considered to be very complex and thus need an advanced technology to help users learning this course more effectively. In this study, we propose and report our research strategy and progress to build a constructive play on human anatomy system based on finger motion gesture of Leap Motion controller (LMC). This LMC device can detect hand gestures and fingers’ motion and translate it into interaction input. Then, we utilize holographic display to portray our 3D human anatomy as its output. In detail, the research strategy of this paper consists of research plan, general framework and general architecture of the developed system. Then, we also present our current development of constructive anatomy learning system. In this future, we will discuss in more detail about the development stage.

Holography can produce the most real three-dimensional (3D) image, and is considered as the ultimate 3D display technology. However, compared with other display technologies, it has not been practically available in video display so far due to low refresh rate. To realize dynamic holographic display, photosensitive material doped liquid crystal (LC) has been discovered and deeply investigated because of superior photorefractive and photoelectric properties. In this work, we present a dynamic holographic display using LC film doped with perovskite (CsPbBr3) nanocrystal (NC) as the photorefractive material. The dependence of diffraction efficiency and response time on doping concentration, recording beam power and applied voltage are investigated. A maximum diffraction efficiency of 18% has been achieved under a low electric field intensity of 0.45 V/μm and the shortest build-up time of grating is 5.5 ms. The system can realize a video display with 60 Hz refresh rate in red, green and blue colors, which demonstrates the feasibility of applying perovskite NC doped LC film in dynamic holographic display.

We demonstrate an interactive holographic display system for real-time drawing and erasing of 3D point-cloud images. This system detects the position of the observer’s fingertip with a motion sensor, which it uses to calculate the complex amplitude distribution for the hologram. Because the calculated distribution is added to or subtracted from the complex amplitude distribution of the previous frame, the calculation time per frame is independent of the number of points comprising the 3D point cloud. Then, the system can quickly update the hologram even when the number of points comprising the 3D point cloud is increased. Because the 3D point-cloud image reconstructed from the calculated hologram is projected at the same position as the observer’s fingertip with almost no latency, the system can draw and erase a 3D point-cloud image through interactions with the observer’s fingertip. We experimentally confirmed that the system successfully draws and erases a 3D point-cloud image.

Electromagnetic metasurfaces are structured surfaces consisting of a thin array of subwavelength elements with engineered scattering properties, thus providing a promising means of holographic display by controlling the field distributions. However, the existing metasurface holography has limited capabilities in achieving 3-D fields with simultaneous features of high spatial resolution and energy efficiency due to the design methods. In this work, we present a transmissive metasurface to achieve polarization-dependent field distributions in 3-D space with both high resolution and efficiency. In the design, a new method that utilizes dyadic Green’s function (DGF) as the rigorous propagator is used. Using the method, the sources and fields are linked directly and can be located on arbitrary 3-D points with the intermediate spaces being equal or unequal. The design is successfully validated by full-wave simulations and experimental measurements. The broadband simulation results indicate that the design has a bandwidth of 0.8 GHz. This work demonstrates a feasible and simple route of field synthesis for real-world applications that require high resolution, high efficiency, and 3-D scenarios.

AIMS AND OBJECTIVES The research aims to identify the technology of producing the holographic image and how to display it through 3D LED fans for use in the field of advertising. HYPOTHESIS AND METHODOLOGIES The research relied on the descriptive analytical approach to produce holographic images, as well as the experimental approach to reach the best methods for producing and designing a holographic display through 3D LED fans. 1. The use of 3D LED fans for a holographic display in advertising is more effective than using traditional methods. 2. Modern technology has helped to develop the concept of stereoscopic image and its spread. 3. Display product pictures through holographic technology more attractive than traditional methods. 4. Graphics and electronic montage programs have helped increase the quality of the images used in the field of advertising. 5. The angle of rotation of the subject during shooting affects the display quality. Results: 1- Displaying product pictures through holographic technology more attractive than traditional methods. 2- Graphics and electronic editing software helped in controlling the quality of the displayed images. 3- The angle of rotation of the subject during shooting affects the quality of the presentation. 4-The rotation time affects the quality of video during the presentation. 5- Image quality control has an effect on presentation.

The enhanced-NA Fresnel hologram reconstructs a holographic image at a viewing angle larger than the diffraction angle of a hologram pixel. The image space is limited by the bandwidth of a digital hologram. In this study, we investigate the property of image formation in the extended image space beyond a diffraction zone. A numerical simulation using the phase Fresnel hologram is carried out to observe an extension of image space and the effect of this on the changes in the angular field of view. The phase Fresnel hologram, synthesized by restricting the angular view range to a diffraction angle, can reconstruct a uniform image without high-order noises within the primary viewing zone, which is well confirmed by optical experiments. On the other hand, the overlapping of high-order images is inevitable when the viewing angle depends on the hologram numerical aperture. The high-order images are distributed in the direction cosine space, which could be effectively removed through an angular low-pass filter. We discuss the development of method for expanding the image space while maintaining the viewing angle of a holographic image., Comment: 22 pages, 9 figures

Holographic displays promise unprecedented capabilities for direct-view displays as well as virtual and augmented reality applications. However, one of the biggest challenges for computer-generated holography (CGH) is the fundamental tradeoff between algorithm runtime and achieved image quality, which has prevented high-quality holographic image synthesis at fast speeds. Moreover, the image quality achieved by most holographic displays is low, due to the mismatch between the optical wave propagation of the display and its simulated model. Here, we develop an algorithmic CGH framework that achieves unprecedented image fidelity and real-time framerates. Our framework comprises several parts, including a novel camera-in-the-loop optimization strategy that allows us to either optimize a hologram directly or train an interpretable model of the optical wave propagation and a neural network architecture that represents the first CGH algorithm capable of generating full-color high-quality holographic images at 1080p resolution in real time.

Holography is arguably the most promising technology to provide wide field-of-view compact eyeglasses-style near-eye displays for augmented and virtual reality. However, the image quality of existing holographic displays is far from that of current generation conventional displays, effectively making today's holographic display systems impractical. This gap stems predominantly from the severe deviations in the idealized approximations of the "unknown" light transport model in a real holographic display, used for computing holograms. In this work, we depart from such approximate "ideal" coherent light transport models for computing holograms. Instead, we learn the deviations of the real display from the ideal light transport from the images measured using a display-camera hardware system. After this unknown light propagation is learned, we use it to compensate for severe aberrations in real holographic imagery. The proposed hardware-in-the-loop approach is robust to spatial, temporal and hardware deviations, and improves the image quality of existing methods qualitatively and quantitatively in SNR and perceptual quality. We validate our approach on a holographic display prototype and show that the method can fully compensate unknown aberrations and erroneous and non-linear SLM phase delays, without explicitly modeling them. As a result, the proposed method significantly outperforms existing state-of-the-art methods in simulation and experimentation - just by observing captured holographic images.

Since its discovery almost 70 years ago, the hologram has been considered to reproduce the most realistic three dimensional images without visual side effects. Holographic video has been extensively researched for commercialization, since Benton et al. at MIT Media Lab developed the first holographic video systems in 1990. However, commercially available holographic video displays have not been introduced yet for several reasons: narrow viewing angle, bulky optics and heavy computing power. Here we present an interactive slim-panel holographic video display using a steering-backlight unit and a holographic video processor to solve the above issues. The steering-backlight unit enables to expand the viewing angle by 30 times and its diffractive waveguide architecture makes a slim display form-factor. The holographic video processor computes high quality holograms in real-time on a single-chip. We suggest that the slim-panel holographic display can provide realistic three-dimensional video in office and household environments., Holographic displays that are both compact and produce realistic holograms without eyestrain are still difficult to realize. Here the authors implement a steering-backlight unit and a holographic video processor to produce a realistic holographic display in a slim panel.

Speckle reduction is an important topic in holographic displays as speckles not only reduce signal-to-noise ratio but also possess an eye-safety issue. Despite thorough exploration of speckle reduction methods using partially coherent light sources, the trade-off involved by the partial coherence has not been thoroughly discussed. Here, we introduce theoretical models that quantify the effects of partial coherence on the resolution and the speckle contrast. The theoretical models allow us to find an optimal light source that maximizes the speckle reduction while minimizing the decline of the other terms. We implement benchtop prototypes of partially coherent holographic displays using the optimal light source, and verify the theoretical models via simulation and experiment. We also present a criterion to evaluate the depth of field in partially coherent holographic displays. We conclude with a discussion about approximations and limitations inherent in the theoretical models.

This report discusses the effect of speckle size on the quality of holographic images based on a liquid-crystal-on-silicon (LCoS) spatial light modulator (SLM). Further, it proposes methods of quantifying the average speckle size and holographic image resolution. These methods enable both characteristics to be compared using the same unit (the number of pixels in the holographic image), providing an intuitive and effective comparative analysis method. In particular, by varying the LCoS resolution ratio, the change in the resolvable minimum pixels of the holographic image is interpreted in conjunction with the average speckle size; moreover, an analysis of the correlation between the latter two is presented. This approach, based on LCoS resolution division, could provide useful insights into single-SLM-based, full-color holographic displays using space division. Furthermore, it could be extended to other components, including more advanced LCoS SLMs, and used to identify the relative effects on image quality with speckles.

In this paper, we propose a dynamic direct-writing optical holographic display system based on quantum-dot-doped liquid crystal (QDDLC). Instead of using two-beam interference to generate the desir...

Displays play an extremely important role in modern information society, which creates a never-ending demand for the new and better products and technologies. The latest requirements for novel display technologies focus on high resolution and high color gamut. Among emerging technologies that include organic light-emitting diode (OLED), micro light-emitting diode (micro-LED), quantum dot light-emitting diode (QLED), laser display, holographic display and others, QLED is promising owing to its intrinsic high color gamut and the possibility to achieve high resolution with photolithography approach. However, previously demonstrated photolithography techniques suffer from reduced device performance and color impurities in subpixels from the process. In this study, we demonstrated a sacrificial layer assisted patterning (SLAP) approach, which can be applied in conjunction with photolithography to fabricate high-resolution, full-color quantum dot (QD) patterns. In this approach, the negative photoresist (PR) and sacrificial layer (SL) were utilized to determine the pixels for QD deposition, while at the same time the SL helps protect the QD layer and keep it intact (named PR-SL approach). To prove this method’s viability for QLED display manufacture, a 500-ppi, full-color passive matrix (PM)-QLED prototype was fabricated via this process. Results show that there were no color impurities in the subpixels, and the PM-QLED has a high color gamut of 114% National Television Standards Committee (NTSC). To the best of our knowledge, this is the first full-color QLED prototype with such a high resolution. We anticipate that this innovative patterning technique will open a new horizon for future display technologies and may lead to a disruptive and innovative change in display industry.

Computer generated holograms represent a novel digital media that with adequate processing tools and the advance of holographic display technologies will foster the development of true immersive video technologies applications. A digital hologram typically conveys a considerable amount of data making compression and image quality evaluation tools necessary for the development of practical applications. This paper proposes an objective evaluation of the performances of state-of-the-art compression techniques applied to digital holographic data. The experimental analysis takes into account several holographic images reconstructing the holograms from different perspectives and distances. The results of the exploratory study are reported, discussed and complemented with a statistical analysis of the hologram data under test, providing insights for computer-generated holography compression techniques design.

Regarded as a kind of smart surfaces, metasurfaces can arbitrarily tailor the amplitude, phase, and polarization of light. Metasurfaces usually consist of subwavelength nanoantenna or nanoresonator arrays, which are delicately designed and processed. As an ultrathin, miniaturized versatile wavefront modulation device, metasurfaces have great information capacity and can arouse the future development of highly integrated micronano optoelectronic systems. Exploiting the advantages of ultrasmall pixels, flexible design freedom, low loss, and easy processing properties, metasurfaces provide potential feasibility and new perspectives for a plethora of applications. Here we review the research progress of metasurfaces for holographic displays, polarization conversion, active modulation, linear and nonlinear wavefront modulation, and prospect the future development trend of metasurfaces.

In this paper, a method of speckle noise suppression for holographic zoom display based on layered-pixel-scanning (LPS) algorithm is proposed. Different from the traditional algorithm, the proposed method suppresses the speckle noise based on a new algorithm design and light source optimization. The LPS algorithm is designed to calculate the phase-only hologram of the 3D object. By extracting the initial complex hologram of the 3D object and scanning the hologram by pixel, the errors of the complex amplitude can be reduced as much as possible. Then a hologram subsampling method based on the LPS algorithm generated is proposed, so the scaling of the reproduced image can be achieved easily. At the same time, the pattern with different random phase is generated and loaded on the spatial light modulator so that the reconstructed light can be optimized. When the optimized light irradiates on the phase hologram of the object, the reconstructed image with suppressed speckle noise can be displayed. The experimental results show that the proposed method has an excellent reproduction effect. Moreover, the feasibility and unique advantages of the proposed method in the holographic augmented-reality display, zoom display and multi-plane display have been proved. We believe that this method can promote the application of the holographic display.

With significant advances in holographic display technology, a plethora of interactive applications, such as tele-conferencing and tele-surgery, are well on their way to integrating holographic technologies. However, hologram-based applications will place significant demands on networking infrastructure, which are not supported today. These include support for ultra-low delays, high bandwidth, and the ability to coordinate, synchronize, and dynamically adapt multiple data streams. This article articulates these challenges and points out gaps in existing networks that solutions must address. In addition, it provides an experimental analysis of novel network architectures that address one of these challenges, namely the ability to dynamically set up new flows with very low latency incurred by the first packet.

Herein, the design and implementation of a transparent 3D touch‐enabled surface for richer user interaction with midair 3D virtual objects in a touch‐interactive pseudo‐holographic display are presented. Frustrated total internal reflection (FTIR)‐based touch sensing is used in combination with a four‐sided pyramidal pseudo‐holographic projection. The developed system allows gesture‐based control and smooth touch interaction through facile and inexpensive hardware and open‐source software tools. A software application is also developed as the interface between the touch/gesture‐sensing system and the optical display. By bringing the virtual and real world closer through touch‐based interaction, the presented system will enrich user experience and enable advances in areas such as education, entertainment, gaming, retail, and museums where holograms are currently used.

Engineered three-dimensional (3D) tissues that replicate composite in-vivo architectures have shown great potential for use in biomedical research. Cell-encapsulated hydrogel micro-scaffolds have been applied widely as basic building blocks to construct these artificial tissues. However, accurate reproduction of heterogeneous hierarchical structures and different regional mechanical properties inside a single integrated micro-scaffold that mimics physiologically relevant complex tissues presents a major challenge. Here, we propose a novel fabrication control algorithm to achieve high-accuracy photolithography of micro-scaffolds that recapitulate the high fidelity of native tissues by adjusting a 3D digital mask using holographic imaging feedback. By performing digital holographic reconstruction to express the hydrogel photocuring process in a matrix form and presetting the curing duration for each discrete point, the 3D digital mask was predefined to represent the required customized micro-scaffold. During fabrication, the UV exposure area was divided into microscaled grids with relatively uniform irradiance to control the photocuring process discretely for every local region in the entire architecture. The holographic imaging feedback allowed the curing duration of each grid to be adjusted in real-time, which enabled accurate reproduction of a 3D construct integrated with different microstructural morphologies and mechanical properties. Finally, PEGDA and GelMA, as typical biomaterials, were used to fabricate the heterogeneous hierarchical micro-scaffold. The structural accuracy was improved from 65 m to 12 m and the Youngs modulus was controlled flexibly in the 27.93.5 to 91.23.5 kPa range. With different local mechanical properties, cell migration in the micro-scaffold from soft to stiff areas is observed successfully.

Reflection and refraction images are treated as the texture of the object in computer graphics, which brings wrong depth information when focusing on the object in holographic display. In this paper, a method of ray tracing rendering with complete depth information for computer-generated hologram(CGH) is proposed. Correct depths of reflection and refraction images are calculated, and layer-based method is used to generate CGH. In experiment result, our method truthfully reconstructs the complete depth information of complex scene. Reflection or refraction images and its corresponding media surfaces can be focused on correct depth. All layer data is computed in a single ray tracing procedure, and the generation speed of 1024×1024 CGH for 3D scene divided into 10 layers is 100fps.

For augmented reality applications, the micro display panels are generally used, as a straightforward method for display engines. But there are the light efficiency and vergence accommodation conflict problems, which affect the performance and application of the AR glasses, HMD and HUDs. One way to solve the problem is to use holography display instead of direct display, which exploit the diffraction light instead of reflection light of the liquid crystal panel. One of the big problems is the form factor of holographic systems which use SLM. Most of current SLMs are composed of a driver board with FPGA and a liquid crystal on silicon panel. The FPGA driver board is big and very power consuming, which makes it better for general SLM systems that cares more about changing the driving algorithm flexibly rather than make it a wearable gadget. A compact SLM system is designed specifically for AR applications, which replaced the normally used FPGA system with a driver IC and greatly reduce they whole system size and power consumption while realize the same function for holographic display. The driver IC could receive the RGB signal or MIPI signal and transform the standard picture signal to a high frame rate color sequential signal, also the gray scale could be tuned through on chip registers either beforehand or instantly, which makes it good for liquid crystals working in different wavelength. The driver board is 2*6 cm2 with a type-C connector which could easily transmit image data from a laptop or a cellphone. This form factor is almost the same with monocular glasses. The power consumption of the driver IC is around 250mW for the driver IC comparing to the normally 5W power of FPGAs. Also, the frame rate could be from 60 to 120 Hz. A simple Fourier holography optical system is used to demonstrate the holographic display, with a lens tear apart from a smart glass on the market. The 3D holographic is displayed in the lens.

Holographic displays enable the formation of a three-dimensional particle field distribution and is promised to be one solution of the key problems in present virtual and augmented reality displays. The biggest challenge in the computer-generated holography (CGH) is the high consuming calculation time and the restricted field of view due to the micro display screen. In order to solve the above mentioned problems, we propose a method for machine learning accelerated lensless holographic projection, which is based on the reconstruction of complex amplitude image from phase-only CGH. The runtime of generating the phase-only CGH is half of traditional iterative method. The complex amplitude image can achieve the maximum diffraction bandwidth of the spatial light modulator (SLM). The feasibility of this method is verified by experiments.

Augmented reality head-up displays (HUDs) require virtual-object distance matching to the real scene along an adequate field of view (FoV). At the same time, pupil-replication-based waveguide systems provide a wide FoV while affording compact HUDs. To provide 3D imaging and enable virtual-object distance matching in such waveguide systems, we propose a time-sequential autostereoscopic imaging architecture using a synchronized multi-view picture generation and eyebox formation units. Our simulation setup to validate the system feasibility yields an FoV of 15° × 7.5° with clear crosstalk-less images with a resolution of 60 pix/deg for each eye. Our proof-of-concept prototype with reduced specs yields results that are consistent with the simulation in terms of the viewing-zone formation. Thus, viewing zones for the left and right eyes in plane of the eyebox can be clearly observed. Finally, we discuss how the initial distance of the virtual image can be set for quantified fatigue-free 3D imaging, and an FoV can be further extended in such types of waveguide systems by varying parameters of the eyebox formation unit.

Three-dimensional (3D) light-field displays (LFDs) suffer from a narrow viewing angle, limited depth range, and low spatial information capacity, which limit their diversified application. Because the number of pixels used to construct 3D spatial information is limited, increasing the viewing angle reduces the viewpoint density, which degrades the 3D performance. A solution based on a holographic functional screen (HFS) and a ladder-compound lenticular lens unit (LC-LLU) is proposed to increase the viewing angle while optimizing the viewpoint utilization. The LC-LLU and HFS are used to create 160 non-uniformly distributed viewpoints with low crosstalk, which increases the viewpoint density in the middle viewing zone and provides clear monocular depth cues. The corresponding coding method is presented as well. The optimized compound lenticular lens array can balance between suppressing aberration and improving displayed quality. The simulations and experiments show that the proposed 3D LFD can present natural 3D images with the right perception and occlusion relationship within a 65° viewing angle.

The viewing-angle enlargement of a holographic image is a crucial factor for realizing the holographic display. The numerical aperture (NA) of digital hologram other than a pixel specification has been known to determine the angular field extent of image. Here, we provide a valid foundation for the dependence of viewing angle on the hologram numerical aperture by investigating mathematically the internal structure of the sampled point spread function showing a self-similarity of its modulating curves. The enhanced-NA Fresnel hologram reconstructs the images at a viewing angle larger than a diffraction angle by a hologram pixel pitch where its angle value is expressed in terms of the NA of whole hologram aperture, which is systematically observed by optical hologram imaging. Finally, we found that the aliased replica noises generated in the enhanced-NA Fresnel diffraction regime are effectively suppressed within the diffraction scope by a digitized pixel. This characteristic enables us to overcome the image reduction and to remove the interference of high-order images, which leads to the wide viewing-angle holographic display. Optical experiments are shown to be consistent with the results of numerical simulation., Comment: 29 pages, 10 figures

The autostereoscopic 3D display has two important indicators, both the number of viewpoints and display resolution. However, it's a challenge to improve both the viewpoint and the resolution. Here, we develop a fixed-position multiview and lossless resolution autostereoscopic 3D display system that includes the dynamic liquid crystal (LC) grating screen. This display system consists of an LC display panel and an LC grating screen. The synchronization of the frame switching of the LC display panel and the LC grating screen shutter enables the preserved resolution. The “eye space” design makes the viewpoint dense enough and determines the LC grating screen's parameters. We use binocular viewpoint tracking technology to realize the LC grating screen's adaptive control based on the above work. Different binocular views are rendered in real-time according to the different positions of a single pair of stereoscopic viewpoints in the eye space, making the motion parallax possible. We present the working principle and mathematical analysis. We implement a prototype for verifying the principle. According to the experiment results analysis, this prototype can achieve viewpoint tracking and motion parallax based on resolution lossless and viewpoint dense enough.