Browsing by Author "Hung, Chien-Hsiang"

Now showing 1 - 8 of 8

An iterative model of diffuse illumination from bidirectional photometric data
(2009-01-19)
Tien, Chung-Hao
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Hung, Chien-Hsiang
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光電工程學系
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顯示科技研究所
;
光電工程研究所
This paper presents a methodology for including the photometric raw data sets into the diffuse illumination design process. The method is based on computing the luminance distribution on the outgoing side of diffusing elements from measured bidirectional scattering distribution functions (BSDFs). The model is limited to specimens that create rotationally symmetric scattering distribution. The calculation procedure includes the linear superposition and the correcting feedback. As an application example, the method is verified by a commercially available diffusing sheet illuminated by a 32-inch backlighting module. Close agreement (correlation coefficient = 98.6%) with the experimental measurement confirmed the validity of the proposed procedure. (C) 2009 Optical Society of America
Microlens array by ink-jet technology for LCD backlight applications
(2008)
Hung, Chien-Hsiang
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Yu, Tsung-Han
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Cheng, Jung-An
;
Chang, Chi-Hsien
;
Hsiau, Yi-Hau
This research uses Ink-jet printer process to fabricate microlens on the bottom of a LGP in a fast and cost-effective way. Compared with typical dot printing method, Ink-jet printing is able to save 50% material consumption. In addition, the microlens with UV-curable epoxy could be well controlled in the radius, contact angle and arbitrary arrangement. A 20x20cm(2) LGP can be fabricated with desired microlens pattern within 10 seconds, which exhibits a potential to apply ink-jet process upon the high-speed mass production.
Microlens Arrays by Direct-Writing Inkjet Print for LCD Backlighting Applications
(2009-04-01)
Tien, Chun-Hao
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Hung, Chien-Hsiang
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Yu, Tsung-Han
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光電工程學系
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顯示科技研究所
In this paper, we demonstrated the Inkjet print method to fabricate a ultraviolet (UV)-curable epoxy microlens deflecting array with controllable curvature and filling factor, by which a 7-in light guide plate with 82% uniformity and 70% light efficiency was successfully implemented. The microlenses can be directly formed by plastic discharged by inkjet head, eliminating the need for molds and slashing development time. Proposed method will certainly has a promising impact on rapid proto-typing and other specialized microfeatures due to its simplicity and versatility.
Modeling Diffuse Components by Bidirectional Scatter Distribution Function for LCD Applications
(2009)
Hung, Chien-Hsiang
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Tien, Chung-Hao
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光電工程學系
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Department of Photonics
This paper presents a methodology for including the photometric rain data sets into the diffuse illumination in display system. The method is based on computing the luminance distribution on the outgoing side of diffusing elements from measured bidirectional scattering distribution functions (BSDFs). The calculation procedure includes the linear superposition and the feedback. As an application example, the method is verified by a commercially available diffusing sheet illuminated by a 32-inch backlighting module. Close agreement (correlation coefficient = 98.6%) with the experimental measurement confirmed the validity of the proposed procedure.
Optical Properties of Visible-light Excited Phosphor Sheet (VEPS) System
(2009)
Xiao, Bo-Wen
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Hung, Chien-Hsiang
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Huang, Hsin-Tao
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Huang, Yi-Pai
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Tien, Chung-Hao
The optical properties in Visible-light Excited Phosphor Sheet (VEPS) system were discussed and calculated. Different to the conventional LED backlight with white LEDs, VEPS system applies blue LED chips to excite the extrinsic flat YAG-phosphor layer to perform uniform and flat lighting, that can further reduce the backlight thickness. A theoretical model was developed to optimize the structure of VEPS system. Consequently, the optimized result was demonstrated on the small-sized VEPS module.
Phosphor-converted LED modeling by bidirectional photometric data
(2010-09-13)
Hung, Chien-Hsiang
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Tien, Chung-Hao
;
光電工程學系
;
顯示科技研究所
;
光電工程研究所
For the phosphor-converted light-emitting diodes (pcLEDs), the interaction of the illuminating energy with the phosphor would not just behave as a simple wavelength-converting phenomenon, but also a function of various combinations of illumination and viewing geometries. This paper presents a methodology to characterize the converting and scattering mechanisms of the phosphor layer in the pcLEDs by the measured bidirectional scattering distribution functions (BSDFs). A commercially available pcLED with conformal phosphor coating was used to examine the validity of the proposed model. The close agreement with the measurement illustrates that the proposed characterization opens new perspectives for phosphor-based conversion and scattering feature for white lighting uses. (C) 2010 Optical Society of America
Planar Lighting by Blue LEDs Array with Remote Phosphor
(2010)
Tien, Chung-Hao
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Hung, Chien-Hsiang
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Xiao, Bo-Wen
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Huang, Hsin-Tao
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Huang, Yi-Pai
A novel direct-emitting LED backlit for LCDs was demonstrated. Unlike the conventional white LED schemes for display applications, proposed blue light excited planar lighting (BLPL) exploits blue LED chip to remotely excite the YAG-phosphor film and thus render a uniform planar source, where the YAG-phosphor acts as the diffuser film and wavelength down converter simultaneously. Based on the diffusing characterization of YAG-phosphor layer, we examined the optical properties of the BLPL system in viewpoints of uniformity, luminance and mixing capability. Consequently, a prototype 10-mm-thickness BLPL module was demonstrated with 86% uniformity and 9800 nits without using any diffuser film or light guiding plate.
UV excited flat lighting (UFL) system for LCD-TV backlight application
(2008)
Huang, Hsin-Tao
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Hung, Chien-Hsiang
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Huang, Yi-Pai
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Tien, Chung-Hao
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Tsai, C. C.
Different to the conventional visible-CCFL backlight, UV excited flat lighting (UFL) applies UV-CCFL to irradiate 254 nm wavelengths to excite extrinsic phosphor layer to perform uniform and flat lighting for LCD-TV applications. UFL can yield longer life time due to less phosphor damage. Additionally, high color rendering, minor color deviation, wider FWHM (Fall width at half maximum) angle, and better lamp mura relaxation, were demonstrated to achieve a high quality display with slim backlight module.