Browsing by Author "Chien, Ming-Chin"

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Cluster LEDs mixing optimization by lens design techniques
(2011-07-04)
Chien, Ming-Chin
;
Tien, Chung-Hao
;
光電工程學系
;
顯示科技研究所
;
Department of Photonics
This paper presents a methodology analogous to a general lens design rule to optimize step-by-step the spectral power distribution of a white-light LED cluster with the highest possible color rendering and efficiency in a defined range of color temperatures. By examining a platform composed of four single-color LEDs and a phosphor-converted cool-white (CW) LED, we successfully validate the proposed algorithm and suggest the optimal operation range (correlated color temperature = 2600-8500 K) accompanied by a high color quality scale (CQS > 80 points) as well as high luminous efficiency (97% of cluster's theoretical maximum value). (C) 2011 Optical Society of America
Computational Lighting by a LED-based System
(2012)
Chien, Ming-Chin
;
Tien, Chung-Hao
;
光電工程學系
;
Department of Photonics
A methodology analogous to a general lens design rule was proposed to step-by-step optimize the spectral power distribution (SPD) of a composite light-emitting diodes (LEDs) cluster. The computation is conducted for arbitrary SPD combination for the applications in radiometry, photometry and colorimetry, respectively. Based on the matrix computation, a spectrally tunable source is implemented to strategically manipulate the chromaticity, system efficiency and light quality according to all kinds of operational purposes. By the R/G/B/A/CW light engine with graphic utility interface, the cluster engine was experimentally validated to offer a wide-ranged operation in ambient temperature (T-a = 10 degrees C to 100 degrees C) with high color quality scale (CQS > 85 points) as well as high luminous efficiency (LE > 100 lm/watt) over the chromaticity point from 2800K to 8000K.
LED light lit for field-sequential-color backlight system
(2007)
Chien, Ming-Chin
;
Chen, Cho-Chih
;
Yang, Su-Chin
;
Lu, Yen-Hsing
;
Kuo, Hao-Chung
A 7-inch backlight module consisting of ten isolated micro-structured linear light pipes and two side-collimating bars was developed with serial full-color Light Emitting Diodes (LEDs) as light source for a field-sequential-color liquid-crystal display (FSC-LCD) system. The collimating lighting system not only yields a narrow angular light distribution, but also effectively diminishes the occurrence of color dependence in the scanning backlight for FSC applications. For each linear light pipes, only 3. 6 % of optical power leaked out to the neighboring divisions, meanwhile, the divergent angles of extraction light were controlled to +/- 17 degrees and +/- 31 degrees at two orthogonal directions respectively.
Multispectral mixing scheme for LED clusters with extended operational temperature window
(2012-03-12)
Chien, Ming-Chin
;
Tien, Chung-Hao
;
光電工程學系
;
顯示科技研究所
;
光電工程研究所
LEDs have changed the concept of illumination not only in an expectation of the highest electroluminance efficiency but also in tremendous chances for smart lighting applications. With a cluster mixing, many studies were addressed to strategically manipulate the chromaticity point, system efficiency and color rendering performance according to different operational purposes. In this paper, we add an additional thermal function to extend the operational thermal window of a pentachromatic R/G/B/A/CW light engine over a chromaticity from 2800K to 8000K. The proposed model is experimentally validated to offer a full operable range in ambient temperature (T-a = 10 degrees to 100 degrees C) associated with high color quality scale (above 85 points) as well as high luminous efficiency (above 100 lm/watt). (C) 2012 Optical Society of America
Multispectral mixing scheme for smart LED-based lighting system
(2012)
Chiang, Song-Bor
;
Chien, Ming-Chin
;
Tien, Chung-Hao
;
光電工程學系
;
Department of Photonics
LED cluster is probably the most relevant among the emerging solid-state lighting techniques. Impressive scenarios of a wide range of color quality and luminous efficiency have been obtained, mostly at the condition of constant ambient temperature. This paper removes the constraint in ambient temperature. We present a methodology analogous to a general lens design rule to optimize step-by-step the spectral power distribution of a white-light LED cluster. The scheme enables the users to determine the optimal operation to meet requirements such as light efficiency, color quality, or other figures of merit over a wide range of color temperatures. All main factors influencing the spectral power distribution (SPD) are discussed, alongside the implementation of a pentachromatic R/G/B/A/CW platform suitable for clinic use. The result shows the multispectral cluster can be modulated within the color temperature from 2800K to 8000K in the range ambient temperature (10 degrees C similar to 100 degrees C) with high color quality scale (CQS > 85 points) and the possibly highest luminous efficiency.
Region-partitioned LED backlight design for field sequential color LCD
(2007)
Chien, Ming-Chin
;
Tien, Chung-Hao
;
Chen, Cho-Chih
;
Lu, Yen-Hsing
;
光電工程學系
In this paper, a 7-inch backlight module consisting of ten isolated micro-structured linear light pipes and two side-collimating bars was developed with serial full-color LEDs as light sources for a field-sequential-color liquid-crystal display (FSC-LCD) system. The collimating lighting system not only yields a narrow angular light distribution, but also effectively diminishes color dependence in the scanning backlight for FSC applications. The crosstalk of the light from each linear light pipe leaking out to the neighboring divisions was measured; meanwhile, the divergent angles of extraction light were well controlled to about +/- 17 degrees and +/- 30 degrees at two orthogonal directions respectively.
Ultracompact backlight-reversed concentration optics
(2009-07-20)
Chien, Ming-Chin
;
Tung, Yu Lung
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Tien, Chung-Hao
;
光電工程學系
;
顯示科技研究所
We demonstrate a concentration scheme based on a reversed tracing concept utilizing a conventional sidelit backlighting configuration. The optical arrangement consists of a groove sheet and a wedge plate without any coating or surface treatment. The proposed layout simultaneously exhibits two main features: coupling the collimated solar radiance into a wedge plate and guiding the flux to the exit plane of the wedge plate for use in direct daylight. The measurement revealed an optical efficiency of 52% in conjunction with an inverse aspect ratio of 9.51. In addition to the two-dimensional sidelit scheme, the proposed structure can also be rotationally convolved and extended to a three-dimensional solar concentrator with a high concentration ratio, which will certainly have an impact on solar energy and other optical functions because of its simplicity and versatility (C) 2009 Optical Society of America