Browsing by Author "Yang, Tsung-Hsun"

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Analysis of a lens-array modulated coaxial holographic data storage system with considering recording dynamics of material
(2017-09-18)
Yu, Yeh-Wei
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Yang, Chi-Hsiang
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Yang, Tsung-Hsun
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Lin, Shiuan-Huei
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Sun, Ching-Cherng
In the first time, a simulation model with considering the recording dynamics of material is built and is used to simulate evolution of the grating strength of the recorded hologram in a coaxial volume holographic memory system. In addition, phase modulation by lens array in the reference is introduced and observed to perform better diffracted signal quality and higher shifting selectivity, in both simulation and experiment. The use of lens array is found to provide multiple advantages in volume holographic memory system. The new simulation model potentially can be used to precisely design the system to obtain higher diffracted signal quality, higher shifting selectivity, and reduction of M# consumption and increase of storage capacity. (C) 2017 Optical Society of America
Design of a Bicycle Head Lamp Using an Atypical White Light-Emitting Diode with Separate Dies
(2019-12-01)
Lin, Hsin-Jung
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Sun, Ching-Cherng
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Wu, Chi-Shou
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Lee, Xuan-Hao
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Yang, Tsung-Hsun
To the best of our knowledge, this is the first demonstration of a design for a bicycle head lamp with a high-contrast cutoff line using an atypical white light-emitting diode (LED) with two separate dies. The precise optical model was created by setting the weighting factor on the emitting surface. The downward reflector was designed and fabricated to produce a high-contrast cutoff line in both short- and long-axis orientations, but a yellowish outer pattern was observed. A modified two-color optical model was created to describe the yellowish patterns in both orientations and explain the yellowish effect. Such an effect was caused by the larger coverage area of the phosphor than that by the blue dies. To reduce the yellowish effect near the cutoff line, a specific phosphor area was blocked in the experiment. The yellowish effect was greatly reduced, and the contrast across the cutoff line was enhanced. The presented technology is useful for designing a high-contrast light pattern with such an atypical white LED.
Design of an LED Spot Light System with a Projection Distance of 10 km
(2019-10-01)
Wu, Chi-Shou
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Chen, Kuan-Yu
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Lee, Xuan-Hao
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Lin, Shih-Kang
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Sun, Ching-Cherng
We designed a spot light system with an illumination range of 10 km. In the designed system, an appropriate white light-emitting diode (LED) was selected according to the exitance and injection power required. Subsequently, through a first-order optical design, the geometry of the lens and reflector was determined using geometrical calculation. Because the central illuminance of the projection spot of the reflector was 2.5 times that of the cover lens, we first considered the fabrication error of the reflector. According to the adjustment of the optimized distance between the white LED and reflector, we modified the design of the cover lens to fit the new location of the white LED. An LED spot light module containing 16 spot light units was used. The module's power injection was only 68.2 W. Because of the excellent performance of the designed system in terms of the divergence angle of the projection beam and maximum luminous intensity, which were 1.6 degrees and 2,840,000 cd, respectively, the projection distance of the LED spot light module was 3.37 Km, according to the ANSI regulation. Finally, a spot light system with nine modules and capable of achieving a projection distance of 10 km was successfully fabricated.
Gray code encoding and decoding method applied to holographic storage devices
(2009-08-27)
Ou-Yang, Mang
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Chen, Yu-Ta
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Sun, Ching-Cherng
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Yang, Tsung-Hsun
A gray code encoding and decoding method applied to holographic storage devices is proposed. The encoding method uses gray levels of a 2D detector to encode a certain amount of original bits of the original data, and then sends them to a spatial light modulator (SLM) for encryption. The decoding method corrects the received gray levels to the original gray levels, and then compares the maximum gray level with the original gray levels to decode the original gray level into binary data. The proposed encoding and decoding method can better make use of storage locations of the 2D detector and get a code rate close to 1.
Illuminance and Starting Distance of the Far Field of LED-Array Luminaire Operated at Short Working Distance
(2020-05-01)
Sun, Ching-Cherng
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Lin, Yi-Syuan
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Yang, Tsung-Hsun
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Lin, Shih-Kang
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Lee, Xuan-Hao
A luminaire with a light-emitting diode (LED) array can provide hotspot illumination in a short range. Therefore, a design of a luminaire with the largest central illuminance (LCI) and a high uniformity is warranted. In this paper, we present a study of illuminance variation with respect to the distance of an illumination target of a luminaire with LED array. The emission property of the luminous intensity is characterized by the cosine power law or the divergent angle of full width at half maximum (FWHM). A real LED module is designed to create the simulation for different luminaire types. The occurrence of the LCI and the far-field region are observed. Our results demonstrate that the LCI distance remains shorter than the starting distance of the far field (SDFF). To simplify the simulation, we propose the replacement of the real LED module with a point or flat-extended source. Such light sources must be equipped with the specific cosine power factor corresponding to the divergent angle of the FWHM of the LED module. These light sources are acceptable for describing illumination characteristics, including the SDFF. Our results may facilitate the design of LED-array luminaires operated at short working distances, such as reading lighting or illumination in microscopes.
Optical servo with high design freedom using spherical-wave Bragg degeneracy in a volume holographic optical element
(2019-11-25)
Yu, Yeh-Wei
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Shu, Chung-Mou
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Sun, Ching-Cherng
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Hsieh, Po-Kai
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Yang, Tsung-Hsun
A novel optical sensor is proposed and demonstrated with the use of spherical-wave Bragg degeneracy of a volume holographic optical element. Bragg degeneracy can be performed perfectly for a volume hologram written by two plane waves or spherical waves. But only spherical reference light is useful to perform severe shifting selectivity in one direction and Bragg degeneracy in another direction. The experiment corresponding to theoretical simulation was demonstrated in a volume holographic optical element, which was an optical servo for a collinear volume holographic disc. Through clever design, the displacement response of the tracking beam was observed for a magnification magnitude of 980% to the displacement of the probe beam so that the resolution requirement of the photosensor can be reduced. Besides, a high linearity of the displacement response was observed. To discover the design freedom, a theoretical study of the displacement response was done for the servo by two spherical waves. The linearity, the magnification magnitude, and the diffraction efficiency were examined and the property of the Bragg degeneracy was figured out. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Optics and Photonics of Taiwan International Conference: Introduction by the feature editors
(2014-08-01)
Fuh, Andy Y. -G.
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Khoo, Iam Choon
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Lin, Tsung-Hsien
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Huang, Yi-Pai
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Chien, Liang-Chy
This Applied Optics feature issue is dedicated to the Optics and Photonics of Taiwan International Conference (OPTIC 2013), held 5-7 December 2013 in Zhongli (Chung-Li), Taiwan. The conference takes place every year at different universities in Taiwan. This feature issue is particularly focused on a broad range of topics covered under subconference VII (Display Technology), and also includes topics pertaining to display technology under other subconferences. In addition, the feature issue is open to all other researchers in the related area. (C) 2014 Optical Society of America
Optics and Photonics of Taiwan International Conference: Introduction by the feature editors
(2014-08-01)
Fuh, Andy Y. -G.
;
Khoo, Iam Choon
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Lin, Tsung-Hsien
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Huang, Yi-Pai
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Chien, Liang-Chy
This Applied Optics feature issue is dedicated to the Optics and Photonics of Taiwan International Conference (OPTIC 2013), held 5-7 December 2013 in Zhongli (Chung-Li), Taiwan. The conference takes place every year at different universities in Taiwan. This feature issue is particularly focused on a broad range of topics covered under subconference VII (Display Technology), and also includes topics pertaining to display technology under other subconferences. In addition, the feature issue is open to all other researchers in the related area. (C) 2014 Optical Society of America
Phosphor-free GaN-based transverse junction light emitting diodes for the generation of white light
(2006-11-01)
Shi, J. -W.
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Huang, H. -Y
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Wang, C. -K.
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Sheu, J. -K.
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Lai, W. -C.
We demonstrate a GaN-based phosphor-free near-white-light light-emitting-diode (LED) structure that operates in the visible wavelengths and offers broadening and flattening optical bandwidth performance. The incorporation of GaN-based dual wavelengths (blue and green) multiple-quantum-wells with a transverse p-n junction produces a device which can directly generate stable and near visible white-light emissions. The shape of the optical spectra (440-560 nm) are invariable from low to very high levels of bias currents. The problems of nonuniform carrier distribution and bias dependent electrolumineseence. spectra that occur in traditional phosphor-free white-light or near-white-light LEDs (with vertical p-n junctions) are eliminated by the demonstrated structure.
Reduction of phase error on phase-only volume-holographic disc rotation with pre-processing by phase integral
(2020-09-14)
Yu, Yeh-Wei
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Chen, Yuan-Cheng
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Huang, Kun-Hao
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Cheng, Chih-Yuan
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Yang, Tsung-Hsun
In this paper, we present a study of observation of phase error of a volume holographic storage disc during the reading process when the disc is rotated or displaced in the theoretical calculation and the corresponding experiment. This additional phase error will dramatically decrease the bit error rate of a phase-only signal, even applying double-frequency shearing interferometry to retrieve the stored phase signal. Then we propose a novel approach to solve the problem. The stored signal is pre-processed by phase integral along the shearing direction so that applying the integral process to decode the phase signal is not necessary in the readout process. The proposed approach effectively reduces the error in phase retrieval and will be useful when applying double-frequency shearing interferometry in the readout process for volume holographic storage. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Simulation and Comparison of the Lighting Efficiency for Household Illumination with LEDs and Fluorescent Lamps
(2013-10-01)
Sun, Wen-Shing
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Tien, Chuen-Lin
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Pan, Jui-Wen
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Yang, Tsung-Hsun
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Tsuei, Chih-Hsuan
The design of the LEDs lighting in general household illumination was proposed and compared with the fluorescent lighting in this study. Using the LED as a light source would promote energy saving lighting for household illumination purposes. We used the LightTools and DIALux software to design and simulate different standards of illuminance, different correlated color temperatures and different color rendering indices for household environments. The power consumption and efficiency of traditional illuminated light sources and an LED light source with the same standard of illuminance for lighting the household environment were analyzed and compared with each other. Finally, our results show the advantages of using white-light LEDs for lighting and household illumination.
Simulation and Comparison of the Lighting Efficiency for Household Illumination with LEDs and Fluorescent Lamps
(2013-10-01)
Sun, Wen-Shing
;
Tien, Chuen-Lin
;
Pan, Jui-Wen
;
Yang, Tsung-Hsun
;
Tsuei, Chih-Hsuan
The design of the LEDs lighting in general household illumination was proposed and compared with the fluorescent lighting in this study. Using the LED as a light source would promote energy saving lighting for household illumination purposes. We used the LightTools and DIALux software to design and simulate different standards of illuminance, different correlated color temperatures and different color rendering indices for household environments. The power consumption and efficiency of traditional illuminated light sources and an LED light source with the same standard of illuminance for lighting the household environment were analyzed and compared with each other. Finally, our results show the advantages of using white-light LEDs for lighting and household illumination.