This PDF file contains the front matter associated with SPIE Proceedings Volume 9385 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

The response time of the vertically aligned in-plane-switching (VA-IPS) mode with respect to different driving voltages is studied. It is found that the rising time, T_on, is highly related to the square of the electric field between the inter-digit electrodes. Since the dielectric torque exerted on the liquid crystal molecules is proportional to the square of the electric field, one can say that it basically dominates the T_on of the VA-IPS mode. However, there’s evidence showing that the total torque perceived by the LC molecules is not simply caused by the voltage applied to the inter-digit electrodes, but also by the flexoelectricity originating from the splay deformation between the electrodes. This leads to the phenomenon that T_on doesn’t monotonically decrease with the increasing dielectric torque.

Among various liquid crystal display modes, the in-plane switching mode exhibits the widest viewing angle because the liquid crystals are homogeneously-aligned initially and rotate within a plane parallel to the substrates when an in-plane field is applied. However, further improvement is still needed for viewing high-quality dark images from the bisector direction of the crossed polarizers. Several compensation schemes have been proposed to eliminate the off-axis light leakage in a homogeneously-aligned liquid crystal cell. Although a 100:1 iso-contrast contour at an wavelength of 550 nm can cover the entire viewing cone, light leakage at other wavelengths still remains very severe. In this paper we introduce achromatic optical compensation methods using uniaxial films to eliminate the off-axis light leakage at the dark state in homogeneously-aligned liquid crystal cell.Uniaxial films with different dispersion characteristics are used so that they can compensate one another to achieve achromatic optical compensation. The retardation values are optimized through numerical research with the aid of the Poincaré sphere.

The speckle, which is due to the interference of coherent light scattered by a random surface, can severely degrades the image quality. The speckle properties are usually measured by a camera, which takes images of the center of a projection screen. As a result, the effects of different viewing angles are not considered. In this paper, the dependence of speckle contrast ratio on the viewing angles in a laser projection system is studied. Two major effects have been considered in the studies. First, different viewing angles result different projection distances. Secondly, for a rough screen, there exists an angular intensity distribution for the reflected/scattered light, which is determined by the structure of the screen surface. By combining these two effects, the experiment results show that the speckle contrast can vary significantly for different viewing angels. It is found that speckle contrast decreases with increase of viewing angle. As a result, when evaluating the speckle contrast in a laser projection system, the dependence of viewing angle should be considered.

Optical waveguides are considered and investigated for laser beam combining and colour homogenization for use in a three colour laser based display system. A recently developed laser is calibrated and the best method for designing an all-waveguide combining and homogenising system is investigated. Ray tracing simulations are performed and the results are presented. An optical combination of lenses is designed and used for laser beam focusing into a 200 μm fibre core diameter step index silica core multimode fibre. We also designed and simulated a slab waveguide for beam shaping and beam homogenizing.

A front projection autostereoscopic display is proposed. The display is composed of eight projectors and a 3D-imageguided screen which having a lenticular sheet and a retro-reflective diffusion screen. Based on the optical multiplexing and de-multiplexing, the optical functions of the 3D-image-guided screen are parallax image interlacing and viewseparating, which is capable of reconstructing 3D images without quality degradation from the front direction. The operating principle, optical design calculation equations and correction method of parallax images are given. A prototype of the front projection autostereoscopic display is developed, which enhances the brightness and 3D perceptions, and improves space efficiency. The performance of this prototype is evaluated by measuring the luminance and crosstalk distribution along the horizontal direction at the optimum viewing distance. We also propose a rear projection autostereoscopic display. The display consists of eight projectors, a projection screen, and two lenticular sheets. The operation principle and calculation equations are described in detail and the parallax images are corrected by means of homography. A prototype of the rear projection autostereoscopic display is developed. The normalized luminance distributions of viewing zones from the measurement are given. Results agree well with the designed values. The prototype presents high resolution and high brightness 3D images. The research has potential applications in some commercial entertainments and movies for the realistic 3D perceptions.

A 30-view auto-stereoscopic display using angle-magnifying screen is proposed. Small incident angle of Lamp-scanning from exit pupil of projection lens is magnified into large field of view on the observing side. The lamp-scanning is realized by the vibration of Galvano-mirror that synchronizing with the frame rate of the DMD and reflecting the laser illuminator to the scanning angles. To achieve 15-view, a 3-chip DLP projector with frame rate of 720 Hz is used. For one cycle of vibration of Galvano-mirror, steps of 0, 2, 4, 6, 8 10, 12, 14 are reflected on going-path and steps of 13, 11, 9, 7, 5, 3, 1 are reflected on returning path. A frame is divided into two half parts of odd lines and even lines for two views. For each view, 48 half frames per second are provided. A projection lens with aperture-relay module is used to double the lens aperture and separating the frame into two half parts of even and odd lines. After going through the Philips prism, three panels, the scanning 15 spots are doubled to 30 spots and emerge from the exit pupil of the projection lens. The exit 30 light spots from the projection lens are projected to 30 viewing zones by the anglemagnifying screen. A cabinet of rear projection with two folded mirrors is used because a projection lens of long throw distance is required.

Volume Holographic Optical Elements (vHOE) offer angular and spectral Bragg selectivity that can be tuned by film thickness and holographic recording conditions. With the option to integrate complex optical function in a very thin plastic layer formerly heavy refractive optics can be made thin and lightweight especially for large area applications like liquid crystal displays, projection screens or photovoltaic. Additionally their Bragg selectivity enables the integration of several completely separated optical functions in the same film. The new instant developing photopolymer film (Bayfol® HX) paves the way towards new cost effective diffractive large optics, due to its easy holographic recording and environmental stability.

A major bottleneck for large area applications has been the master hologram recording which traditionally needs expensive, large high precision optical equipment and high power laser with long coherence length. Further the recording setup needs to be rearranged for a change in optical design.

In this paper we describe an alternative method for large area holographic master recording, using standard optics and low power lasers in combination with an x, y-translation stage. In this setup small sub-holograms generated by a phase only spatial light modulator (SLM) are recorded next to each other to generate a large size vHOE. The setup is flexible to generate various types of HOEs without the need of a change in the mechanical and optical construction by convenient SLM programming. One Application example and parameter studies for printed vHOEs based on Bayfol® HX Photopolymer will be given.

In this paper, we present a depth enhancing technique for integral imaging (II) system using a varifocal lens array. Expressible depth range of II is restricted in a specific region. If the image gets out of the region, displayed image becomes distorted and broken. The center of the region which called central depth plane (CDP) is defined by the focal length of lens array. In our experiment, liquid lens array is used for II system instead of ordinary solid lens array. The focal length of lens array varies depending on the applied voltage across. As a result, the proposed II system enables control of the location of image planes electrically. With this depth plane controllable system, time multiplexed II system is implemented. For this purpose, two objects of different positions and appropriate voltage level for each object are chosen. In display panel, elemental images for each object are alternately displayed with high frame rate and appropriate voltage levels are applied to the liquid lens array. Because the time period between two sequences is very short, both objects are seems to appear simultaneously. Hence the depth range of the constructed image is enhanced.

In this paper we present a wide viewing angle multi SLMs color holographic 3D display. An extended viewing angle is provided by the use of circular setup configuration. To ensure best utilization of spatial bandwidth of a single SLM a temporal multiplexing method for a color reconstruction is applied. Averaged in time modulated component wavefronts overlap in space and create a real color 3D image. We present the display implementation resulting in color reconstruction of computer generated objects and multi-view 2D real object stereogram converted into holographic representation. The applicability of this approach to allow holographic display of big 3D scenes and the future possibilities to extend the spatio-temporal bandwidth of color holographic displays are discussed.

Quantum dots are a new generation of phosphor material that have high photon conversion efficiency, narrow spectral line-widths and can be continuously tuned in their emission wavelengths. Since 2013, quantum dots have been adopted by the consumer electronics industry into LCDs to significantly increase their color performance. Compared to the OLED solution, quantum dot LCDs have higher energy efficiency, larger color gamut, longer lifetime, and are offered at a fraction of the cost of OLED panels. In this paper, we demonstrate that quantum-dot based LCDs can achieve more than 90% coverage of the ultra-wide color gamut, Rec. 2020, which is the new color standard for UHDTV.

In this paper, we propose a glasses-free random dot stereoacuity test using a multi-view display system. We use a multiview display system with a liquid crystal display panel and a parallax barrier. We generate the random dot base images with different disparities. The multi-view system and the generated base images provide several random dot stereotest images to the patient. The proposed method can offer not only binocular disparity but also motion parallax. We implement 4-view parallax barrier system with a 5K liquid crystal display monitor, and generate the random dot base images for the system. For the practical usage, we also develop graphical user interface of the stereoacuity test which contains the personal calibration function in pixel unit.

We proposed a new method to calculate the color computer generated hologram of three-dimensional object in holographic display. The three-dimensional object is composed of several tilted planes which are tilted from the hologram. The diffraction from each tilted plane to the hologram plane is calculated based on the coordinate rotation in Fourier spectrum domains. We used the nonuniform fast Fourier transformation (NUFFT) to calculate the nonuniform sampled Fourier spectrum on the tilted plane after coordinate rotation. By using the NUFFT, the diffraction calculation from tilted plane to the hologram plane with variable sampling rates can be achieved, which overcomes the sampling restriction of FFT in the conventional angular spectrum based method. The holograms of red, green and blue component of the polygon-based object are calculated separately by using our NUFFT based method. Then the color hologram is synthesized by placing the red, green and blue component hologram in sequence. The chromatic aberration caused by the wavelength difference can be solved effectively by restricting the sampling rate of the object in the calculation of each wavelength component. The computer simulation shows the feasibility of our method in calculating the color hologram of polygon-based object. The 3D object can be displayed in color with adjustable size and no chromatic aberration in holographic display system, which can be considered as an important application in the colorful holographic three-dimensional display.

Holographic display is a promising technique for three-dimensional (3D) display because it has the ability to reconstruct both the intensity and wavefront of a 3D object. Real-time holographic display has been demonstrated in photorefractive polymers. It is expected to carry out dynamic 3D display by recording holograms into a volume holographic polymer due to its high-density storage capacity, good multiplexing property. In this work an updatable 3D display based on volume holographic polymer of photochromic diarylethene is proposed. The photochromic diarylethene polymer is a promising rewritable recording material for holograms with high resolution, fatigue resistance and quick responding of erasure. The computer-generated holograms carrying with wavefronts of 3D objects are written to the diarylethene polymer, and the recorded holograms in the polymer can be easily erased when exposed in ultraviolet light. The 3D scenes can be reconstructed for the write/erase cycles.

Generally, volumetric 3D display panel produce volume-filling three dimensional images. This paper discusses a volumetric 3D display based on periodical point light sources(PLSs) construction using a multi focal lens array(MFLA). The voxel of discrete 3D images is formed in the air via construction of point light source emitted by multi focal lens array. This system consists of a parallel beam, a spatial light modulator(SLM), a lens array, and a polarizing filter. The multi focal lens array is made with UV adhesive polymer droplet control using a dispersing machine. The MFLA consists of 20x20 circular lens array. Each lens aperture of the MFLA shows 300um on average. The polarizing filter is placed after the SLM and the MFLA to set in phase mostly mode. By the point spread function, the PLSs of the system are located by the focal length of each lens of the MFLA. It can also provide the moving parallax and relatively high resolution. However it has a limit of viewing angle and crosstalk by a property of each lens. In our experiment, we present the letter ‘C’, ‘O’, ‘DE’ and ball’s surface with the different depth location. It could be seen clearly that when CCD camera is moved to its position following as transverse axis of the display system. From our result, we expect that varifocal lens like EWOD and LC-lens can be applied for real time volumetric 3D display system.

OLED displays exhibit luminance fluctuations and color shifts that can be sensitive to human eye in particular conditions. Using viewing angle and imaging multispectral measurements we show that color shifts are generally related to the multilayered structure of each sub-pixel. Interference fringes result in angular variations while thickness variations result in surface non-uniformities.

Three-dimensional (3D) display usually provides binocular disparity to observer. To construct 360degree table-top display, lots of views are required. In order to display a large amount of views to observer, time-multiplexing technique is applied. We suggest a new structure for view-sequential 360-degree table-top display system. In my system, a transmissive screen is used and digital micromirror device (DMD) image is projected on it. This system defines the direction of bundle of rays to configure the sequential view. It has some advantages resulting from the transmissive flat screen. When the transmissive screen is used instead of the reflective one, the light power efficiency is improved. Moreover, the arrangement of the pixel is more uniform when the screen is flat instead of a static conic screen. We construct a table-top display with about 288views around 360degree and its feasibilities are confirmed.

We proposed a novel scheme to achieve a computer-generated hologram (CGH). The CGH is generated from a point cloud that is transformed by a mapping relationship of a series of sub-images. The sub-images are converted from elemental images captured by integral imaging pickup system. A more continues depth map can be obtained and a clearer display of the 3D scene can be presented. Moreover, the inherent drawback pseudoscopic problem of integral imaging can also be overcome.