Browsing by Author "Shen, C. -Y."

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A novel lens cap designed for the RGB LEDs installed in an ultra-thin and directly lit backlight unit of large-sized LCD TVs
(2008-02-01)
Chao, Paul C-P.
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Shen, C. -Y.
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Chiu, C. -W.
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Huang, J. -S.
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Kao, Y. -Y.
The objective of this study is to design a novel cone-shaped lens cap on LEDs in order to achieve high optical efficiency in an ultra-thin directly lit RGB LED backlight unit (BLU) for large-sized LCD TVs. The use of the novel lens cap could play the role of a diffuser, a low light-efficiency component in a BLU, in order to gain higher efficiency and simultaneously provide satisfactory uniformity in light distribution. The novel cone-shaped lens is coated with aluminum on the outside surface of the cone for mirroring effects to reflect most of the LED emitted light horizontally and then reflect the light at the BLU boundaries, and then, finally to the output plane. In this way, bright spots on the output plane of the BLU can be avoided, leading to increased uniformity. Simulations were conducted to design and optimize varied aspects of the designed lens and BLU, including the cone angle of the proposed lens and the LED spacing (pitch). To further achieve color balance, a known Genetic Algorithm is used to search for the optimal angular placement of each RGB LED, resulting in better color balance. Finally, a prototype BLU for large-sized 37-in. LCD TVs with the proposed lens was built to verify the expected performance.
Achieving color balance of a large sized BLU directly-lit by LEDs capped with customized optical lenses
(2008)
Chao, Paul C. -P.
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Shen, C. -Y.
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Chiu, C. -W.
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Huang, J. -S.
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Wang, C-L.
The objective of this study is to develop a high color balance thin RGB LED backlight unit (BLU) for large-sized LCD-TVs. Genetic Algorithm is employed to search the optimal angular placement of each RGB LED and gain the condition of better color mixing for achieving high color balance of BLU.
Nanoindentation Study of FePt Thin Films Deposited by Radio Frequency Magnetron Sputtering
(2016-03)
Chiu, Y. -J.
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Shen, C. -Y.
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Jian, S. -R.
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Chang, H. -W.
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Juang, J. -Y.
The microstructural and nanomechanical properties of Fe0.5Pt0.5 (FePt) thin films deposited on the glass substrates by radio frequency magnetron sputtering were investigated. Specifically, this study focused mainly on the effects of post-annealing on the evolvement of film microstructure and its correlation with the associated nano-mechanical properties. The X-ray diffraction (XRD) results indicated the FePt films were largely equiaxed with the average grain size being increased from similar to 27 nm to similar to 105 nm as the annealing temperature was raised from 400 degrees C to 700 degrees C. The associated film hardness and Young\'s modulus, as derived from the nano-indentation measurements, were decreased from 14.4 +/- 6.8 GPa and 194.2 +/- 9.1 GPa to 8.1 +/- 0.2 GPa and 153.8 +/- 6.5 GPa, respectively. The nano-mechanical properties of the present FePt films were well described by the Hall-Petch relation.
Novel lens design for ultra-thin, high efficiency of light utilization, direct type RGB LED backlight module
(2007-01-01)
Shen, C. -Y.
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Chiu, C. -W.
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Chao, Paul C. -P.
;
Huang, J. -S.
;
Wang, C. L.
The objective of this study is to design a novel cone-shaped lens for achieving high optical efficiency for an ultra-thin, direct type RGB LED backlight unit (BLU). The usage of the novel lens could replace the commonly used diffuser plate for gaining higher efficiency and providing satisfactory uniformity of BLU. FMC7- 2