Browsing by Author "Wang, Chih-Ming"

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Efficiency evaluation of a hybrid miniaturized concentrated photovoltaic for harvesting direct/diffused solar light
(2019-03-01)
Tsao, Wei-Chen
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Zeng, Qiu-Chun
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Yeh, Yu-Hsiang
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Tsai, Chih-Hung
;
Hong, Hwen-Fen
In this paper, a miniaturized concentrator photovoltaic (CPV) system is experimentally demonstrated based on a hot embossing silicone lens array with a size of 2 cm x 2 cm. Owing to the small size of the lens array, the total track of the CPV system can be as small as 4 cm. Consequently, the weight of the CPV system can be much lower than conventional bulky CPV system. For harvesting the diffuse solar radiation, perovskite solar cells are mounted adjacent to a multi junction solar cell. Theoretically, the short-circuit current of the CPV system can be enhanced from 48.1 to 85.5 mA for gamma = 0.7. The enhancement can be much higher for off-normal incident light. This kind of hybrid CPV system will be useful for cloudy weather and also useful for compensating the loss caused by the miss-alignment of the tracking module.
Functional imprinting structures on GaN-based light-emitting diodes for light pattern modulation and light extraction efficiency enhancement
(2010-07-01)
Tu, Sheng-Han
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Wu, Shang-Yen
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Lee, Yeeu-Chang
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Pan, Jui-Wen
;
Kuo, Cheng-Huang
In this study, we demonstrated a simple method that can be used to simultaneously modulate the far field pattern and enhance the light extraction of GaN-based light-emitting diodes (LEDs). In this method, microstructures were imprinted on a reliable spin-on-glass surface on top of a transparent conductive layer. The far-field pattern was modulated using microoptical structures, and at the same time, the light extraction was enhanced owing to the small refractive index difference and surface roughness. There was no decrease in the electrical performance of these devices. The peak intensity shifted from 0 to 22A degrees in one-dimensional (1D) asymmetrically blazed periodic structures, and a flattened distribution with a uniform intensity within a span of 110A degrees was observed in two-dimensional (2D) symmetrically periodic structures. This method achieved 13 and 40% light enhancements for 1D and 2D structures, respectively.
Global solution of achromatic Total Internal Reflection prism in projection system
(2018-12-01)
Pan, Jui-Wen
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Li, Jhong-Syuan
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Wang, Chih-Ming
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光電系統研究所
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Institute of Photonic System
In this paper, an achromatic total internal reflection (TIR) prism set, consisting of two stacked prisms, is designed to reduce the lateral color aberration of a mini projector with light-emitting-diode (LED) light sources. Two different types of the prism set are proposed. Type 1 prism set is the first prism with a small Abbe number material stacked with the second prism with a large Abbe number material. By analyzing the optical properties of the proposed ATIR prism sets, we are able to choose an appropriate optical material combination of the prism set. For type 1 prism set, the corresponding lateral color aberration is 0.65 mu m and the size is 2306 mm(3). Nevertheless, the type 1 suffers from efficiency loss of 15.5%. For type 2 prism set, the corresponding lateral color aberration is 0.61 mu m and the compact prism size is 3000 mm(3). Although the size of type 2 prism set is larger than that of type 1, the efficiency loss can be as low as 1%.
High concentration and homogenized Fresnel lens without secondary optics element
(2011-09-01)
Pan, Jui-Wen
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Huang, Jiun-Yang
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Wang, Chih-Ming
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Hong, Hwen-Fen
;
Liang, Yi-Ping
In this paper, we design a single concentrator to homogenize and concentrate the solar energy. The proposed concentrator only consisted of an array of refraction prisms. In order to homogenize the irradiance, all pitches of the Fresnel concentrator focus on the different position of the receiver. Finally, the Fresnel lens that achieves the uniformity of U is 14.6. An acceptance angle of 0.305 degrees is achieved without using additional secondary optics. Full Width at Half Maximum (FWHM) of illumination distribution is 1.4 mm. (C) 2011 Elsevier B.V. All rights reserved.
Integration of Non-Lambertian LED and Reflective Optical Element as Efficient Street Lamp
(2010-06-21)
Pan, Jui-Wen
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Tu, Sheng-Han
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Sun, Wen-Shing
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Wang, Chih-Ming
;
Chang, Jenq-Yang
A cost effictive, high throughput, and high yield method for the increase of street lamp potency was proposed in this paper. We integrated the imprinting technology and the reflective optical element to obtain a street lamp with high illumination efficiency and without glare effect. The imprinting technique can increase the light extraction efficiency and modulate the intensity distribution in the chip level. The non-Lambertian light source was achieved by using imprinting technique. The compact reflective optical element was added to efficiently suppress the emitting light intensity with small emitting angle for the uniform of illumination intensity and excluded the light with high emitting angle for the prevention of glare. Compared to the conventional street lamp, the novel design has 40% enhancement in illumination intensity, the uniform illumination and the glare effect elimination. (C) 2010 Optical Society of America
Optical properties of light emitting diodes with a cascading plasmonic grating
(2010-12-06)
Wang, Chih-Ming
;
Tsai, Yao-Lin
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Tu, Sheng-Han
;
Lee, Chien-Chieh
;
Kuo, Cheng-Huang
In this paper, the polarization dependent optical properties of InGaN/GaN multi-quantum wells (MQWs) LED with cascading plasmonic gratings are investigated using an angle-resolved photoluminescence (ARPL) spectrometer. The plasmonic gratings consist of two Ag gratings with a half-pitch displacement. The ARPL spectra of the TE-TM state present a broadband emission with resonance dips occasioned by the SP resonance while the TM-TE state presents resonance peaks with low sideband emission. The resonance properties can be tuned by modifying the geometric parameters of the plasmonic grating. The ARPL spectrum of the LED sample with pure GaN 1D grating is also measured and discussed. The investigated plasmonics LED represents resonance optical properties different from the conventional surface relief LED, which can be used in special applications. (C) 2010 Optical Society of America
Second Harmonic Light Manipulation with Vertical Split Ring Resonators
(2019-02-15)
Tsai, Wei-Yi
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Chung, Tsung Lin
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Hsiao, Hui-Hsin
;
Chen, Jia-Wern
;
Lin, Ren Jie
The second harmonic generation (SHG) of vertical and planar split-ring resonators (SRRs) that are broken centro-symmetry configurations at the interface of metal surface and air is investigated. Strong interactions, better electromagnetic field confinements, and less leakage into the substrate for vertical SRRs are found. Experimental results show a 2.6-fold enhancement of SHG nonlinearity, which is in good agreement with simulations and calculations. Demonstrations of 3D metastructures and vertical SRRs with strong SHG nonlinearity majorly result from magnetic dipole and electric quadrupole clearly provides potential applications for photonics and sensing.
Single stage transmission type broadband solar concentrator
(2010-06-21)
Wang, Chih-Ming
;
Huang, Hung-I
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Pan, J. W.
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Kuo, Hung-Zen
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Hong, Hwen-Fen
In this paper, a single stage solar cell concentrator is designed and discussed. The proposed concentrator consists of refraction prisms and total internal reflection prisms in the inner and outer areas, respectively. In order to compensate for dispersion, all odd zones gather the light onto the - D position, while all even zones gather the light onto the + D position. Finally, the hybrid concentrator achieves optical efficiency of 89.8% for normally incident light without an antireflection coating. An acceptance angle of +/- 0.78 degrees at 1dB loss is achieved without using additional secondary optics. In addition, the fabrication tolerance is also analyzed. (C) 2010 Optical Society of America