Browsing by Author "Cheng, Yi-Kai"

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Aberration analysis of a wedge-plate display system
(2007-08-01)
Cheng, Yi-Kai
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Chung, Sen-Nien
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Chern, Jyh-Long
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光電工程學系
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Department of Photonics
The aberration characteristics of a wedge-plate display optical system are analyzed. The study shows that a kink-like feature is inherent in the ray-intercept curve due to either the onset of the dark zone in imaging or the coincidence of the ray direction with the vertex. Third-order aberration coefficients are deduced, and the total amount of aberration is investigated to illustrate the basic limitations of image quality in this type of display. The issue of design optimization is also investigated based on the aberration characteristics. A numerical example of a 50 in. display with a 1:10 thickness and a diagonal screen length ratio is also provided. (c) 2007 Optical Society of America.
Analysis and reduction of dark zone in ultra-thin wedge-plate displays
(2006-09-01)
Cheng, Yi-Kai
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Chung, Sen-Nien
;
Chern, Jyh-Long
;
光電工程學系
;
Department of Photonics
A wedge plate can be used as the screen of a display, and the thickness of the display can be incredibly thin. In this paper, a basic formula for ray tracing in such a wedge plate is deduced. The fundamental limitation on the display quality of a wedge plate is explored, and the formation of a dark zone on the display screen is analyzed and verified numerically. Experimental exploration and confirmation of one 14-in. acrylic wedge plate with a white-light-emitting diode is also provided. Two approaches to eliminate the dark zone are proposed, and the corresponding numerical demonstration of a 52-in. wedge-plate display is also shown.
Design of a wedge plate for polarization-preserving angular shifter
(2009-03-01)
Cheng, Yi-Kai
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Chern, Jyh-Long
;
光電工程學系
;
Department of Photonics
It is shown that by using a wedge plate, the incident direction of light propagation can be rotated as necessary while still preserving beam polarization. The basic conditions of these preservations of polarization are deduced. For numerical demonstration, it is shown that a collimated beam with +45A degrees linear polarization can be guided to any pre-settled direction where the square of ellipse ratio variation in the polarization is less than 0.0001%, while the variation of squared ellipse ratio of a right circular polarization beam is kept under 0.1%.
Electrospun Fibers as a Solid-State Real-Time Zinc Ion Sensor with High Sensitivity and Cell Medium Compatibility
(2013-03-25)
Syu, Jia-Hao
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Cheng, Yi-Kai
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Hong, Wun-Yan
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Wang, Hsing-Ping
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Lin, Yu-Chao
meso-2,6-Dichlorophenyltripyrrinone (TPN-Cl2), a probe molecule for zinc II ions, is dispersed in a polymer host. The red fluorescence peak at 620 nm appears when the molecule forms a complex with zinc at its center. TPN-Cl2 has a high selectivity for zinc II and tolerates many common metal ions present in the human body. The probe molecules are blended with a hydrogel polymer, poly(2-hydroxyethyl methacrylate) (poly HEMA), with 30 wt% dimethylformamide (DMF). The fiber structure with 1 m diameter is made by electrospinning in DMF solution of the probe and poly HEMA mixture. The fibrous film detects zinc ions with concentrations as low as 106 M in real-time both in water and in the commonly used cell culture liquid media Dulbecco's modified Eagle medium (DMEM) and fetal bovine serum (FBS), which contain many metal ions and proteins. The time-resolution is 5 min for 106 M and 1 min for 105 M. This sensitivity and response speed satisfy the requirements for non-invasive biomedical studies.
Equiangular-spiral bent lightpipes with arbitrary bent angle
(2009-05-15)
Chu, Shu-Chun
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Cheng, Yi-Kai
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Chern, Jyh-Long
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光電工程學系
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Department of Photonics
A recent study proposed the concept of a leakage-free bent lightpipe with an equiangular-spiral shape [S.-C. Chu, J.-L Chern, Opt. Lett. 30 (2005) 3006]. This paper extends the design of a leakage-free equiangular-spiral bent lightpipe with arbitrary-bend-angle and addresses in detail the mathematical formalism required to build such an equiangular-spiral bent lightpipe. Furthermore, a comparison of the proposed equiangular-spiral bent lightpipe and a conventional circular bent lightpipe is provided. Numerical verifications are discussed, and experimental explorations with different bent shapes and angles are carried out for comparison. Results show that equiangular-spiral bent lightpipes with different bent angles exhibit a theoretical 100% transmission with more than 76% efficiency when practically propagating, which is much better than conventional circular bent lightpipes. The output irradiance distributions of bent lightpipes with different bent shapes are also investigated. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.
Integrated semiconductor optoelectronic devices for real-time and indicator-free detection of aqueous nitric oxide
(2011-01-01)
Wang, Shin-Ping
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Cheng, Yi-Kai
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Chao, Yu-Chiang
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Zan, Hsiao-Wen
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Chang, Gao-Fong
Sensing films specific to nitric oxide and zinc were fabricated by embedding respectively indicator 1,2-diaminoanthraquinone (DAQ) and 11,16-Bis(phenyl)-6,6,21,21-tetramethyl-m-benzi-6,21-porphodimethene (BPDM-H) in hydrogel host poly(2-hydroxyethyl methacrylate). The sensing film contains DAQ, which responses to nitric oxide, shows stability in acid environment. The sensing film contains BPDM-H responses to zinc. The electrospinning technique was also utilized to fabricate the fibrous film.
Irradiance formations of on-axis Lambertian pointlike sources in polygonal total-internal-reflection straight light pipes
(2007-09-01)
Cheng, Yi-Kai
;
Wang, Meng-Hua
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Chern, Jyh-Long
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光電工程學系
;
Department of Photonics
Different geometric shapes of light pipes cause different irradiance distributions. We analytically explore the irradiance distributions of on-axis Lambertian pointlike sources in polygonal total-internal-reflection (TIR) straight light pipes. lt is analytically shown that the irradiance of pentagonal light pipes concentrates on the center of the exit plane. Numerical verifications are also provided, and experimental explorations with different shapes of acrylic light pipes are carried out for comparison. We also analyze the influence of light-pipe length on distribution uniformity and deduce the smallest uniform-mixing length/circumradius ratios for polygonal light pipes. (c) 2007 Optical Society of America.
Pelarization-preserving angular shifter
(2008-07-01)
Cheng, Yi-Kai
;
Chern, Jyh-Long
;
光電工程學系
;
Department of Photonics
This study shows that by using a wedge plate the incident direction of light propagation can be rotated as desired while still preserving beam polarization. This study also deduces the basic condition of this preservation of polarization. Two typical wedge plates are analyzed for nume:rical demonstration. Simulation results verify that a collimated beam with a +45' linear polarization can be guided to an expected direction while preserving the state of polarization with a square of the variation of the ellipse ratio of less than 0.0001%. This study also numerically shows that the wedge vertex angle is the most critical issue and that approximately 0.1* accuracy is required to preserve the polarization state. (c) 2008 Optical Society of America
Polarization-preserving angular shifter
(2008)
Cheng, Yi-Kai
;
Chern, Jyh-Long
;
光電工程學系
;
Department of Photonics
We propose two types of light pipes, namely wedge and circular forms, the incident direction of light propagation could be rotated as necessary while still preserving beam polarization. We also deduce the basic conditions of these preservations of polarization. Several typical cases of light pipes are analyzed by numerical simulation. As one of the examples, it is verified that a collimated beam with +45 degree linearly polarization can be guided to any pre-settled direction where the ellipse ratio variation in polarization is less than 0. 1%