Browsing by Author "Hung, C. H."

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Aberrations measurement of fiber-end microlens by free-space microoptical Ronchi interferometer
(2006-07-01)
Tien, C. H.
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Hung, C. H.
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Lee, C. H.
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光電工程學系
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顯示科技研究所
We developed a microoptical Ronchi interferometer system in which a V-groove, an out-of-plane grating, a beam splitter, and a 45 degrees upward reflector integrated on a single silicon chip were used to measure the wavefront aberration caused by a microlens on the fiber front end. By the use of the microelectromechanical systems configuration, the fringe patterns caused by the different spherical aberration and defocus balances of the 0.34-numerical-aperture microlens can be captured and analyzed accordingly. As demonstrated by the experimental results, the proposed setup is capable of carrying out a simple wavefront variation measurement in the microscopic scale.
Experimental Platforms and Die Design for Hot Stamping of a Patchwork Blank
(2017-01-01)
Chen, F. K.
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Hung, T. H.
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Hung, C. H.
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Huang, T. B.
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Chen, T. R.
The hot stamping of a patchwork blank is one of the forming processes being applied to manufacture automobile structural parts. In order to perform the finite element analysis for patchwork blank hot stamping process, the material behavior of blank and interface parameters between blank and tools are required in the finite element model. In this paper, the experimental platforms for obtaining interface parameters including coefficient of friction and interface heat transfer coefficient were established. Then, the finite element analysis model for patchwork blank hot stamping process was constructed. The forming mechanisms, stamping die design, and cooling system design were also examined in this study. Finally, the experimental interface parameters and stamping die design were applied to the finite element analysis for the hot stamping of a patchwork part.
Micromachined polarization beam splitter with adjustable leak ratio for optical pickup
(2007-07-01)
Tien, C. H.
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Hung, C. H.
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光電工程學系
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顯示科技研究所
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Department of Photonics
In this letter, we propose the optomechanical design and fabrication of a novel batched-processed polarization beam splitter (PBS) with an adjustable leak ratio for optical recording applications. The micro-PBS was fabricated by a 410-nm low stress silicon nitride Si3N4 membrane integrated with a bimorph actuator. A de drive voltage was applied to allow an adjustable leak ratio (0-0.24) with incident angle from 65 degrees to 75 degrees for operation in the different optical requirements (phase-change and magneto-optical disks) at lambda = 633 nm. The characteristics of the fabricated PBS are in close agreement with the theoretical calculations and confirm its feasibility.
Simulation of Velocity Distribution and Pressure Drop in Every Channel in the Printed Circuit Heat Exchanger
(2013)
Lo, H. P.
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Hung, C. H.
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Wang, C. C.
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機械工程學系
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Department of Mechanical Engineering
This study examines the performance of printed circuit heat exchangers (PCHE) operated at high temperature subject to the influence of inlet conditions. Simulations are made with three cold plates and three hot plates with mass flow ranging from 0.469kg/h to 4.697kg/h. The inlet temperatures of the cold side and hot side are 200 degrees C and 700 degrees C, respectively. The size of the plate is 272x55x1.65mm with straight channel in the cold side and Z-Shape channel in the hot plate. The simulation is carried out for three cases (Case1: V-c = 5 m/s, T-c = 200 degrees C, V-h = 5 m/s, T-h = 700 degrees C; Case2: V-c = 5 m/s, T-c = 200 degrees C, V-h = 10 m/s, T-h = 700 degrees C; Case3: V-c = 1 m/s, T-c = 200 degrees C, V-h = 5 m/s, T-h = 700 degrees C). It is found that the effect of inlet velocity on the temperature performance is quite significant, and the heat transfer coefficient is related to the mass flow rate. The distribution of mass flow rate within the channel casts significant effect on the outlet temperature. The calculated results indicated the effectiveness epsilon (Case1) is 0.72 which is much higher than those of Case2 (0.704) and Case3 (0.574). Yet the second cold plate shows the maximum temperature difference and the pressure drop in all three cases of simulation.