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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

New type transflective liquid crystal displays /

Mak, Hin Yu. January 2008 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2008. / Includes bibliographical references. Also available in electronic version.
12

Bistable twisted nematic liquid crystal display using photoalignment technology /

Yeung, Fion Sze Yan. January 2004 (has links)
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references. Also available in electronic version. Access restricted to campus users.
13

Feature-based automatic registration of images with 2D and 3D models

Zhang, Yan January 2006 (has links)
Automatic image registration is the technique to align images in different coordinate systems to the same coordinate system which has found wide industrial applications for control automation and quality inspection. Focusing on the industrial applications where product models are available and transformations between models and images are global, this thesis presents the research works on two registration problems based on different features and different transformation models. The first image registration problem is a 2D/2D one with a 2D similarity transformation and based on geometric primitives selected from models and extracted from images. Featured-based methods using geometric primitives like point, line segment and circle have been widely studied. This thesis proposes a number of novel registration methods based on elliptic features, which include a point matching algorithm based on local search method for ellipse correspondence search and rough pose estimation, a numerical approach to refine the estimation result by using the non-overlapping area ratio (NAR) of corresponding ellipses and an elliptic are matching algorithm based on integral of squared distances (JSD) between points on corresponding arcs. The major advantage of JSD is that its optimal solution can be obtained analytically, which makes it applicable to efficient elliptic arc correspondence search. The second image registration problem is a 3D/2D one with an orthographic projection transformation and based on silhouette features. A novel algorithm has been developed and presented in this thesis based on a 3D triangular-mesh model, which can be applied to approximate a de facto NURBS model, and images in which silhouette features can be extracted. The algorithm consists of a rough pose estimation process with shape comparison methods and a pose refinement process with 3D/2D iterative closest point (ICP) method. The computer simulation results show that the algorithm can perform very effective and efficient 3D/2D registration.
14

Prediction of the behaviour of light in light pipes for LCD instrument clusters

Al-Akaidi, Marwan Muhammad Hussain January 1988 (has links)
Liquid Crystal Displays are commonly used in automotive dashboards. The back lighting necessary for a Liquid Crystal Display (LCD) can be achieved by the use of a light source and a light box, light pipe, or a diffusing screen. The space constraints of an automobile dashboard often mean that the light pipe is the most suitable method of illumination. At present an optimum design for the light pipe is obtained by a "Cut and Try" approach in which several light pipes are usually moulded and tested before a satisfactory candidate is found. This thesis reports on experimental and theoretical work to improve the legibility and readability of 'on' and 'off' segments of liquid crystal displays and to automate the design of the light pipes using Computer-Aided Design.
15

Exploring the Use of 360 Degree Curvilinear Displays for the Presentation of 3D Information

Bolton, John 01 February 2013 (has links)
In this thesis we examine 360 degree curvilinear displays and their potential for the display of 3D information. We present two systems: a spherical display prototype and a cylindrical display. Our spherical display prototype used the lack of set user position and natural visibility constraints of a spherical display to create a 3D display system that treated the sphere as a volumetric display through the use of 360 degree motion parallax and stereoscopy. We evaluated these properties by examining how our use of stereoscopy and 360 degree motion parallax, might aid in the preservation of basic body orientation cues and in pose estimation tasks in a telepresence application with our final cylindrical display. Results suggest the combined presence of 360 degree motion parallax and stereoscopic cues within our cylindrical display significantly improved the accuracy with which participants were able to assess gaze and hand pointing cues, and to instruct others on 3D body poses. The inclusion of 360 degree motion parallax and stereoscopic cues also led to significant increases in the sense of social presence and telepresence reported by participants. / Thesis (Master, Computing) -- Queen's University, 2013-01-29 14:14:33.822
16

Territoriality and Behaviour On and Around Large Vertical Publicly-Shared Displays

Azad, Alec 22 May 2012 (has links)
Large displays and information kiosks are becoming increasingly common installations in public venues to provide an efficient self-serve means for patrons to access information and/or services. They have evolved over a relatively short period of time from non-digital, non-interactive static displays to more elaborate media-rich digital interactive systems. While the content and purposes of kiosks have changed, they are still largely based on the traditional single-user-driven design paradigm despite the fact that people often venture to these venues in small social groups, i.e., with family and/or friends. This often limits how groups collaborate and forces transactions to be serialized. This thesis explores design constraints for interaction by multiple social groups in parallel on shared large vertical displays. To better understand design requirements for these systems, this research is separated into two parts: a preliminary observational field study and a follow-up controlled study. Using an observational field study, fundamental patterns of how people use existing public displays are studied: their orientation, positioning, group identification, and behaviour within and between social groups just-before, during, and just-after usage. These results are then used to motivate a controlled experiment where two individuals or two pairs of individuals complete tasks concurrently on a low-fidelity large vertical display. Results from the studies demonstrate that vertical surface territories are similar to those found in horizontal tabletops in function, but their definitions and social conventions are different. In addition, the nature of use-while-standing systems results in more complex and dynamic physical territories around the display. We show that the anthropological notion of personal space must be slightly refined for application to vertical displays.
17

Birefringence, anisotropic shrinkage and luminance in injection molded light-guide plate modeling and experiment /

Lin, Tsui-Hsun. January 2009 (has links)
Dissertation (Ph. D.)--University of Akron, Dept. of Polymer Engineering, 2009. / "May, 2009." Title from electronic dissertation title page (viewed 11/27/2009) Advisor, Avraam I. Isayev; Committee members, James L. White, Thein Kyu, Kevin Kreider, Shi-Qing Wang; Department Chair, Sadhan C. Jana; Dean of the College, Stephen Cheng; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
18

Bistable twised nematic liquid crystal displays by inhomogeneous alignment surfaces /

Lee, Chung Yung. January 2009 (has links)
Includes bibliographical references.
19

Opto-Electronic Processes in SrS:Cu ACTFEL Devices

Rajagopalan, Dharmashankar 01 January 2006 (has links)
The a. c. thin film electroluminescent (ACTFEL) devices are of scientific interest due to their applications in large area, flat panel displays. Of particular interest to the research community is the mechanism of electron transport and luminance in these devices. Toward this end, a physical model and a mathematical model for SrS:Cu ACTFEL Devices were developed and published earlier by our group. The purpose of this thesis is to obtain a qualitative and quantitative match between experiment and theory. A brief summary of the model can be found here [1]. Effects of variation in drive parameters in experimental steady state measurements, and analysis of VIL (Voltage-Current-Luminance) plots for different simulated device and drive parameters are performed. The effects of voltage amplitude, activator concentration, interface energy levels, and critical field for dipole collapse were studied. The plots matched qualitatively in that all major experimental features were produced in the simulated waveforms. The measured and the simulated peak currents are 72.5 mA/cm2 and 66.42 mA/cm2 for VA = 123 V. Experimental and theoretical charge transferred per pulse were 2.75 C/cm2 and 2.26 C/cm2. Peak experimental and simulated luminance values for VA = 123 V were 531 cd/m2 and 49150 cd/m2. Total experimental and simulated luminance values for VA = 123 V case were 6.2 cd/m2 and 561.2 cd/m2 respectively. The large difference is attributed to the loss factors such as optical losses (due to total internal reflection), scattering of electrons by impurities in the bulk phosphor layer, and concentration quenching; these have not been incorporated in the model yet.
20

Analysis of Electron Transport and Luminance Mechanisms in SrS Based Blue Emitting ACTFEL Devices

Sivakumar, Praveen 01 January 2003 (has links)
The purpose of this thesis is to contribute to the understanding of SrS based ACTFEL devices. Better understanding of the processes in the host phosphor will give us the possibility to design more efficient blue emitting ACTFEL devices. Towards this aim, a physical model, that describes the optoelectronic processes taking place in the phosphor, was developed and analytical equations were written. The analytical model was numerically simulated and the plots of flux flowing through the device and luminance output by the device were obtained. Experiments were performed to obtain the plots of current flowing through the device and luminance output by the device. These plots were then qualitatively compared and the results of comparisons are presented. The numerical simulations qualitatively verify the accuracy of the model. The drive parameters were varied in order to study its effect on the VIL characteristics of the device. On varying the voltage applied to the device and its rise and fall times, a good insight was obtained into device behavior. Simulations were also performed to obtain responses to qualitatively match the experimentally obtained responses. Various What-If scenarios have been studied by varying the device parameters. These studies have indicated the importance of these parameters in determining device performance.

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