1,720,956 research outputs found
Design of Diffractive Color Separation Grating for Optimized Power and Color Performance
No full text現行的液晶顯示系統中利用彩色濾光片來達到全彩的效果是非常普遍且必要的，然而利用彩色濾光片，會使光使用效率下降至只有33%。為了解決這個問題，我們在現有的液晶顯示系統裡，在背光源和彩色濾光片之間加入分光光柵結構，以達到讓背光源經過此光柵結構後分別分成紅色、綠色及藍色，且分別射入不同次像素。
我們利用Fraunhofer 繞射理論為基礎來模擬分析光柵結構並且分析其繞射效率以及色彩表現。我們利用調整光柵參數(包含光柵階數、光柵高度以及中心波長)，分別對三種不同的光源(CCFL、UHP和LEDs)來做模擬。
從模擬的結果得知，在加入光柵結構後光的使用效率跟傳統CCFL系統比可以增加93.8%，且在色空間方面可以增加20.8%。對於UHP和LEDs 光源而言，光使用效率分別增加91%及107%，並且色空間分別增加10.2%及12.7%。所以我們可以藉由加入分光光柵結構來同時達到提高光的使用效率，並且增加色域空間的結果。It is fundamental to use the color filter (CF) in LCD system to achieve a full-color display. For this purpose, however, the total power efficiency will plummet to 33% when the light passes through the CF. In order to alleviate this problem, we have developed a novel approach by inserting a diffractive color separation grating between the backlight and the CF to spatially separate the RGB (red, green, and blue) lights and then the three bands can be directed into three different corresponding sub-pixels. We simulated such multiple-level gratings based on Fraunhofer diffraction theory and analyze the diffraction power efficiency and color performance for the new backlight systems. We take three different light sources (CCFL, UHP, and LED) as our simulation examples and design the corresponding grating structure (the period, step and height of the grating) for each light source. The simulation results we derived for CCFL backlight demonstrate that we can get the best power efficiency improvement by 93.8% as compared with the conventional system. The gamut area can be improved by 20.8% as well. For the other two backlight systems (UHP and LED), we can design the gratings and get the best brightness efficiency improvement by 91% and 107% and gamut area improvement by 10.2 % and 12.7%, respectively. In conclusion, by adopting this novel approach we can successfully achieve the goal of improving total power efficiency and enhance the color performance at the same time.摘要 ii
Abstract v
Table of Contents vii
Chapter 1 Introduction 1
1.1 Display Technology 1
1.2 Introduction of Liquid Crystal Display System 2
1.3 Micro-optics Device 3
1.4 Diffraction optics element 4
1.5 Fabrication of diffraction optics element 4
1.6 Motivation 6
1.7 Content 7
Chapter 2 Principle of Color Separation Gratings 8
2.1 Phenomenon of Diffraction 8
2.2 Definition of Helmholtz-Kirchhoff 9
2.3 Diffraction Formula of Rayleigh-Sommerfeld 13
2.4 Diffraction Formula of Fresnel and Fraunhofer 15
2.5 The Damman grating 18
2.6 Color separation grating used in LCD system 21
Chapter 3 Simulation Result and Discussion of Optical Performance 22
3.1 Analysis of Changing the Parameter of CSGs 22
3.1.1 Changing the number of steps 23
3.1.2 Changing the height of step 25
3.1.3 Changing the Central Wavelength of CSG 26
3.2 The Setting of Parameters for CSGs 27
3.2.1 The Setting of Red CSG (RCSG) 27
3.2.2 The Setting of Green CSG (GCSG) 30
3.2.3 The Setting of Blue CSG (BCSG) 31
3.2.4 Period Setting of CSGs 33
3.3 The CSG Setting and Simulation Result for CCFL 35
3.4 The CSG Setting and Simulation Result for UHP 51
3.5 The CSG Setting and Simulation Result for LED Light Source 67
3.6 Color Performance 83
Reference 8
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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