The Experts below are selected from a list of 125631 Experts worldwide ranked by ideXlab platform
Cheng-tang Pan - One of the best experts on this subject based on the ideXlab platform.
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Design and fabrication of double-sided Optical Film for OLED lighting
Optics Communications, 2013Co-Authors: C.f. Liu, Cheng-tang Pan, Y. C. Chen, Zin-huang LiuAbstract:Abstract Design and fabrication of Optical Films to increase visual brightness of OLED (Organic Light-Emitting Diode) lighting units are presented in this paper. This study explores a new fabrication process combining precision machining, photolithography, and micro forming techniques to make a double-sided Optical Film. One side of the Optical Film is made of micro triangular-pyramidal array (MTPA), and the other side is micro gapless hexagonal microlens array (GHMA). First, Taguchi Method is applied to determine the optimal microstructure configuration by the assistance of the commercial Optical software, FRED. Second, tungsten (W) mold of MTPA as the first mold is manufactured by precision machining including Optical projection grinding, lapping, and polishing processes. Nickel–cobalt (NiCo) mold of GHMA as the first mold of the other side is fabricated by using LIGA (Lithographie Galvanoformung Abformung)-like process. To obtain inverse molds, poly dimethylsiloxane (PDMS) is used to replicate W and Ni–Co molds, which are served as the secondary molds for two sides, respectively. With these molds, UV (ultraviolet) curable resin was used to make double-sided Optical Film. Then the Optical Film was packaged on OLED unit to measure its Optical properties by PR 650 equipment. The result shows that both brightness and uniformity can be improved by using this Film.
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Compound Optical Film Using Gray Scale Mask Embedded with Micro-Voids
Applied Mechanics and Materials, 2013Co-Authors: Y. C. Chen, Cheng-tang Pan, Yao-shen Chen, Hung-wei YangAbstract:This study presents a compound Optical Film to improve luminance and uniformity to apply in side-LED (Light-emitting diode) backlight module. LIGA (Lithographie GalVanoformung Abformung) technology, soft lithography and homemade gray scale mask were combined to fabricate micro-lens array. Optical Film with variable size micro-lens array embedded with micro-voids was designed and manufactured. FRED software was used to simulate Optical performance. Micro-voids were quantitatively embedded in the PDMS (Polydimethylsiloxane) Optical Film. Under the quantitative control of air pressure, those micro-voids inside the Optical Film can cause light diffusion. The compound Optical Film with embedded micro-voids, multi aspect ratio and variable size micro-lens array can be fabricated quickly without substrate. Luminance Colorimeter BM-7A from TOPCON was used to carry out the Optical measurement. According to the measured data, the compound Optical Film with embedded micro-voids can enhance the luminance up to 5% and the uniformity up to 6.5% ~ 8.4%. The Optical efficiency can be improved via the compound Optical Film.
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Application of Optical Film with micro-lens array on a solar concentrator
Solar Energy, 2011Co-Authors: J. K. Tseng, Cheng-tang Pan, Yao-shen Chen, M.h. ChungAbstract:Abstract A plastic solar concentrating Optical Film with horizontal cylinder micro-lens array (HCMA) is presented in this study. The solar concentrator (SC) is in the form of Optical Film with HCMA and it is attached on the surface of a solar cell. This Film is a polymethylmethacrylate (PMMA)-based Optical layer. Compared with a plain solar collecting Optical Film without HCMA, the solar collecting Optical Film with HCMA can reduce the opportunity of reflection as light arrives at the surface and therefore can increase the refraction coefficient. As a result, the gain of photovoltaic power can be improved with the SC. Light is efficiently refracted by the HCMA and absorbed by the solar cell without the need of a solar tracking mechanism. Optimization of geometrical parameters of HCMA such as contact angle and gap (interspace) between each horizontal cylinder micro-lens is designed by simulation. The procedures of fabrication include reflow process, nickel–cobalt (Ni–Co) electroplating, and molding process. The measurement equipment of NEWPORT Oriel 91160+MODEL 6285 is utilized to measure the parameters such as open-circuit voltage V oc , short-circuit current I sc , and fill factor F . F ., relating to the efficiency of the complete system. The experimental results show that a gain of photovoltaic power of about 3.30% is obtained with a contact angle of 62° and a gap of 15 μm.
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Fabrication of gapless triangular micro-lens array
Sensors and Actuators A: Physical, 2007Co-Authors: Cheng-tang PanAbstract:Abstract This study presents a new process to fabricate gapless triangular micro-lens array (GTMA) Optical Film. The process includes ultraviolet (UV) lithography, photoresist reflow process, Ni–Co electroplating and hot embossing technique. After photoresist triangular column array is defined by UV lithography, reflow technique is applied to melt photoresist triangular column array into the shape of triangular micro-lens array. With this reflowed triangular micro-lens array, metal Ni–Co is deposited and covered uniformly on the triangular micro-lens array using electroplating process. The growth rate of Ni–Co is controlled at 0.4–0.6 μm/min at electroplating current density of 1 A/dm 2 (ampere square decimetre, ASD). After this electroplating process, a mold of GTMA is obtained, which is served as the primary mold. Next, with passivation technique applied on this primary mold's surface, a secondary mold is obtained by applying the electroplating process again. This secondary mold is served as master for the subsequent hot embossing process to replicate the GTMA pattern onto polymeric material of polymethyl methacrylate (PMMA) sheet. The Ni–Co mold with hardness over hardness of vicker (Hv) 650 is obtained. The stiffness and hardness of the mold play important roles in GTMA hot embossing process. In addition, this PMMA-based GTMA Film used as Optical Film offers a 100% fill factor and high Optical coupling efficiency to improve luminance. The Optical measurement shows that this Optical Film with GTMA pattern increases 15.1% of luminance for backlight module (BLM) of liquid crystal display (LCD).
H Dotsch - One of the best experts on this subject based on the ideXlab platform.
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magneto Optical nonreciprocal phase shift in garnet silicon on insulator waveguides
Optics Letters, 2004Co-Authors: Richard L Espinola, Richard M. Osgood, T Izuhara, Mingchu Tsai, H DotschAbstract:We demonstrate the integration of a single-crystal magneto-Optical Film onto thin silicon-on-insulator (SOI) waveguides by use of direct wafer bonding. Simulations show that the high confinement and asymmetric structure of SOI allows an enhancement of ∼3× over the nonreciprocal phase shift achieved in previous designs; this value is confirmed by our measurements. Our structure will allow compact magneto-Optical nonreciprocal devices, such as isolators, integrated on a silicon waveguiding platform.
J C Huang - One of the best experts on this subject based on the ideXlab platform.
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Optical Film for LED with Triangular-Pyramidal Array Using Size-Reducible Embossing Method
Journal of Materials Engineering and Performance, 2011Co-Authors: C.f. Liu, C. T. Pan, K. H. Liu, Y. C. Chen, J. L. Chen, J C HuangAbstract:This study presents a modified hot-embossing process to fabricate micro-triangular-pyramidal array (MTPA). First, a tungsten (W) steel mold (as the first mold) is manufactured by precision machining including Optical projection grinding, lapping, and polishing processes. The dimension of a triangular pyramid with acute angle of 85° on the W-steel mold is about 300 μm in width and 139 μm in height. The pitch between two triangular-pyramidal tips is about 170 μm. Then, only the portion of the tip area of the triangular-pyramidal patterns is transferred on bulk metallic glass (BMG, Mg_58Cu_31Y_11) using this modified multi-step hot-embossing method to reduce the pattern size. With a position-adjustable mechanism, size-reduced concaved-shaped MTPA can be selectively formed, used as the secondary mold. In this way, not only can the size of triangular-pyramidal patterns on W-steel mold be reduced down on BMG, but also the tool arc between each triangular-pyramid on W-steel mold caused by machine tool can be eliminated. This is based on the fact that amorphous glass alloys contain no dislocation that can be responsible for yielding in crystalline materials. Thus, BMG is expected to be strong and hard enough to be used as a mold material. Then the secondary mold is used to emboss convex-shaped MTPA on PolymethylMethacrylate (PMMA) Optical Film. Experiments with different embossing times and embossing pressures are conducted and discussed. Large-sized triangular-pyramidal array on the W-steel mold has been successfully and selectively miniaturized on BMG, and then transferred on PMMA. Finally, this Optical Film of PMMA with MTPA is packaged on light-emitting diode (LED) to improve its lighting uniformity and luminance. In comparison with commercial 3M^™ Optical Film (3M^™ Vikuiti^™ TBEF2-T-65i), the Film with MTPA shows a good Optical performance.
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fabrication of gapless dual curvature microlens as a diffuser for a led package
Sensors and Actuators A-physical, 2009Co-Authors: M. F. Chen, S D Tseng, P. J. Cheng, J C HuangAbstract:Abstract The light-emitting diode (LED) has been the subject of much interest in the role of a backlight module for liquid crystal displays (LCDs). However, a traditional LED lamp is a point-light source, and so is not suitable for use in large LCD panels. This study presents a new packaging method for LEDs, which uses a gapless dual-curvature microlens array (GDMLA) to improve its ability to illuminate a panel. GDMLAs of different dimensions were simulated and fabricated in order to examine their light luminance and uniformity. Commercial Optical simulation software, “Tracepro”, was used to obtain a GDMLA of optimized geometry and dimensions. Based on the simulated data, a GDMLA mold was first fabricated using a LIGA-like process (Lithographie Galvanoformung Abformung, LIGA); this was known as the first mold. In this study, the first mold was obtained using a nickel cobalt (Ni–Co) electroplating process. In order to obtain a highly accurate and strong mold, a bulk metallic glass (BMG) alloy, Mg58Cu31Y11, was chosen as the material for the second mold, which exhibits excellent forming ability and high hardness. The pattern of the first mold was replicated onto BMG by hot-embossing, and the shrinkage between the first and the second mold was less than 0.2%. Next, the pattern of the GDMLA on the second mold was replicated onto ultraviolet (UV)-curable resin, producing the final Optical Film for a LED package. The shrinkage between the second mold and the UV-cured Optical Film was less than 0.4%; this means that the process exhibits a high replication ability. The fabricated GDMLA had the characteristics of dual curvatures and a high fill-factor of 100%. The light uniformity of the LED package with the GDMLA Optical Film was measured, and the results demonstrated that the GDMLA is a good Optical device for use in LED packages. In addition, the relationship between the simulation and experimental results is assessed and discussed.
Chang-pin Chou - One of the best experts on this subject based on the ideXlab platform.
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Experimental Study of a Silver Layer on an Antireflection Subwavelength-Structured Surface
IEEE Photonics Technology Letters, 2008Co-Authors: Chia-jen Ting, Chi-feng Chen, Chang-pin ChouAbstract:The Optical characteristics of a silver layer deposited on an antireflection subwavelength-structured surface are investigated. The experimental results of the reflectance and the transmittance of several different thicknesses of silver layer on the subwavelength-structured surface are carried out. A subwavelength structure with the spatial period and diameter of about 230 nm and height of about 150 nm on polyethylene terphthalate Film is fabricated by microreplication process. It is shown that such an element with the suitable silver layer deposited on an antireflection subwavelength-structured surface has high transmittance and low glare in the visible spectral range and high reflectance in the infrared range. Obviously, the Optical Film with silver layer can not only obtain the high performance of heat insulation but also give an application in automobile and house windows.
Chia-jen Ting - One of the best experts on this subject based on the ideXlab platform.
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Improved antireflection properties of an Optical Film surface with mixing conical subwavelength structures
Journal of Nanomaterials, 2013Co-Authors: Chi-feng Chen, Yu-cheng Cheng, Chia-jen TingAbstract:Based on finite difference time domain method, an Optical Film surface with mixing conical subwavelength structures is numerically investigated to improve antireflection property. The mixing conical subwavelength structure is combined with the pure periodic conical subwavelength structures and the added small conical structures in the gap between the pure periodic conical subwavelength structures. The antireflection properties of two types of subwavelength structures with different aspect ratios in spectral range of 400-800 nmare analyzed and compared. It is shown that, for the mixing type, the average reflectance is decreased and the variances of the reflectance are evidently smaller. When the added structure with a better aspect ratio exists, the average reflectance of the surface can be below 0.30%. Obviously, the antireflection properties of the Optical Film surface with mixing conical subwavelength structures can be improved.
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fabrication of an antireflective polymer Optical Film with subwavelength structures using a roll to roll micro replication process
Journal of Micromechanics and Microengineering, 2008Co-Authors: Chia-jen Ting, Chi-feng Chen, Fuhyu Chang, C P ChouAbstract:An antireflective Optical Film with subwavelength structures replicated by use of a roll-to-roll micro-replication process (RMRP) is investigated. Firstly, a single layer of a nanostructure on a polymer Film is designed for an antireflection purpose by the finite difference time domain method in the visible light spectrum. Structures of a conical cylinder array, with spatial period of 400 nm, diameter of 200 nm and height of 350 nm, are numerically obtained. Then, such structures are fabricated by RMRP combining originated structure fabrication realized by deep ultra-violet lithography and dry etching, Ni mold electroplating and replication by using the roll-to-roll process imprinting into the flexible polyethylene terephthalate substrate. A nanostructure roller mold bonded with Ni molds has been successfully fabricated and coated with the self-assembly monolayer process for the purpose of fabricating an anti-adhesion Film and improving the lifetime of the Ni molds. The duplicated nanostructure Films show a good Optical quality of antireflection (AR ≤ 2.45% in a 400–700 nm spectral range) and are in good agreement with the theoretical predictions. The experimental results show that the developed process is a promising and cost-effective method for the continuous duplication of flexible devices with nano-scaled feature sizes used in nanophotonics by RMRP.
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Experimental Study of a Silver Layer on an Antireflection Subwavelength-Structured Surface
IEEE Photonics Technology Letters, 2008Co-Authors: Chia-jen Ting, Chi-feng Chen, Chang-pin ChouAbstract:The Optical characteristics of a silver layer deposited on an antireflection subwavelength-structured surface are investigated. The experimental results of the reflectance and the transmittance of several different thicknesses of silver layer on the subwavelength-structured surface are carried out. A subwavelength structure with the spatial period and diameter of about 230 nm and height of about 150 nm on polyethylene terphthalate Film is fabricated by microreplication process. It is shown that such an element with the suitable silver layer deposited on an antireflection subwavelength-structured surface has high transmittance and low glare in the visible spectral range and high reflectance in the infrared range. Obviously, the Optical Film with silver layer can not only obtain the high performance of heat insulation but also give an application in automobile and house windows.
