Browsing by Author "Huang, Hsin-Tao"

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A Direct-View Backlight With UV Excited Trichromatic Phosphor Conversion Film
(2010-04-01)
Huang, Hsin-Tao
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Tsai, Chuang-Chuang
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Huang, Yi-Pai
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光電工程學系
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顯示科技研究所
This work presents a novel ultraviolet (UV) excited flat lighting (UFL) system consisting of remote phosphor converter (RPC) for liquid-crystal display (LCD) backlight applications. A trichromatic RPC is excited using 254 nm UV lamps to achieve a slim, high color saturation and high luminance backlight. Experimental results indicate that the module thickness reduces to 14.5 mm, along with a high color saturation (92% of the NTSC standard) as well as a high luminance (573 cd/m(2)) when applied to large sized display (42-inch). Additionally, the proposed UFL backlight configuration has already been certified by a lifetime test to ensure the feasibility of proposed system in mass production.
Conformal phosphor coating using pulsed spray to reduce color deviation of white LEDs
(2010-06-21)
Huang, Hsin-Tao
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Tsai, Chuang-Chuang
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Huang, Yi-Pai
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光電工程學系
;
顯示科技研究所
This work presents a novel "pulsed spray (PS)" process for the coating of yellow YAG:Ce3+ phosphor on blue InGaN-based light emitting diodes (LEDs). To coat a phosphor layer of high quality on an LED chip surface, the PS approach is used and studied because of the uniform color distribution, providing a wide range of color temperatures. This PS coating approach applies phosphor by exploiting mechanical principles without risk of chemical pollution. Additionally, it can be applied to wire-bonded LEDs and an array of LED chips on a substrate to fabricate a large-area, planar illumination system of high optical quality, which is easy to manufacture. (C) 2010 Optical Society of America
Dual-Sided Slim LCD Display System with UV Excited Flat Backlight
(2009)
Huang, Hsin-Tao
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Tsai, Chuang-Chuang
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Huang, Yi-Pai
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Hsiao, Chun-Chung
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Chen, Sung-Po
Dual-sided LCD displays are ideally suited for the public information display (PID) application. The UV excited flat lighting (UFL) was successfully demonstrated to perform dual-sided illumination with the features of flat lighting, uniform luminance and high brightness on a 42 '' TFT-LCD display. Compared to conventional CCFL or LED lighting source, UFL is superior for the dual-sided display application with its slim backlight module profile and power saving.
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 Conformal Coating by a Novel Spray Method for White Light-emitting Diodes as Applied to Liquid-crystal Backlight Module
(2009)
Huang, Hsin-Tao
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Tsai, Chuang-Chuang
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Huang, Yi-Pai
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Chen, Jerry
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Lin, Jeremy
This work presents a novel pulsed spray process (PSP) for the conformal coating of yellow YAG:Ce(3+) phosphor on blue InGaN-based light emitting diodes (LEDs) for TFT-LCD backlight applications. This new approach exhibits much greater color spatial uniformity than conventional white LEDs coated with YAG phosphor by dispensing method. Unlike conformal coating by electrophorestic deposition (EPD), this new phosphor coating scheme of PSP represents an environmental friendly solution without Cr ion pollution. Additionally. PSP can be combined with an array blue chips on board (COB) in a manner that is compatible with large-area processing with high manufacture throughput, and can reduce the costs of TFT-LCD backlight applications.
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.
Planar Lighting System Using Array of Blue LEDs to Excite Yellow Remote Phosphor Film
(2011-01-01)
Huang, Hsin-Tao
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Huang, Yi-Pai
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Tsai, Chuang-Chuang
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光電工程學系
;
顯示科技研究所
This investigation demonstrates a novel light-emitting system with an array of blue light-emitting diodes (LEDs). Unlike a conventional lighting system that is constructed from white LEDs, the proposed planar lighting system uses blue LEDs to excite a YAG : Ce(3+) yellow phosphor film remotely, yielding a high lumen efficiency with uniform and planar light-emission. The phosphor film herein acts as a wavelength converter and a light diffuser simultaneously. The optical properties of the proposed lighting system, angular color deviation and light-emitting uniformity, are studied. Eventually, a high lumen efficiency (73.0 lm/W) and thin lighting module (7.5 mm-thick) was demonstrated without the use of any conventional diffuser plate or light guiding plate (LGP). A low color deviation (Delta u'v' = 0.025) and a high light-emitting uniformity (U(niformity) = 82%) were achieved. Hence, the proposed lighting system exhibited superior optical performance using a compact module.
Ultraviolet excitation of remote phosphor with symmetrical illumination used in dual-sided liquid-crystal display
(2010-08-01)
Huang, Hsin-Tao
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Tsai, Chuang-Chuang
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Huang, Yi-Pai
;
光電工程學系
;
顯示科技研究所
The UV-excited flat lighting (UFL) technique differs from conventional fluorescent lamp or LED illumination. It involves using a remote phosphor film to convert the wavelength of UV light to visible light, achieving high brightness and planar and uniform illumination. In particular, UFL can accomplish compact size, low power consumption, and symmetrical dual-sided illumination. Additionally, UFL utilizes a thermal radiation mechanism to release the large amount of heat that is generated upon illumination without thermal accumulation. These characteristics of the UFL technique can motivate a wide range of lighting applications in thin-film transistor LCD backlighting or general lighting. (C) 2010 Optical Society of America
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.