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Item type:Item, Design of aspheric lens to collimate and uniform irradiance of a light source with Lambertian angular distribution(2006-01-01) ;Cheng, Chieh-Jen ;Chern, Jyh-Long ;光電工程學系Department of PhotonicsA design of aspheric lens is proposed to collimate a light source of Lambertian angular distribution and generate homogenous irradiance. Two numerical solutions were calculated. One used even orders of general aspheres to describe the aspheric surfaces and the performance was evaluated by commercial optical software package Tracepro. Both of high numerical aperture (NA) of 0.79 and good RMS uniformity within 95% of designed area in the second surface of lens could be obtained. The reverse of this lens would be used in focusing and the simulated point spread function (PSF) is almost diffraction-limited. The other fitted both of aspheric surface with radial spline surface and the performance was evaluated by commercial optical software package OSLO. With the radial spline surface representation, the aspheric lens has a higher NA of 0.9; meanwhile, the uniformity was still good enough and PSF is also near diffraction-limited.Item type:Item, Liquid crystal lenses with tunable focal length(2017-01-01) ;Lin, Yi-Hsin ;Wang, Yu-Jen ;Reshetnyak, Victor ;光電工程學系Department of PhotonicsLenses with tunable focal length play important roles in nature by helping species avoid predators and capture prey. Many practical devices mimic lens concept for imaging, sensing, and detection. This review covers fundamental optics of lenses and its extension to lenses made of liquid crystals (LCs). Three main types of LC lenses are described, namely, lenses with curved surfaces, flat gradient-index lenses and composite lenses. The review discusses advantages of LC lenses over their isotropic counterparts, challenges in their fabrication and control, as well as a variety of potential applications. We also discuss the current challenges associated with nematic LC lenses and their solutions. LC lenses are already having significant impacts on optics and optometry, and these impacts will grow with discovering new LC materials and new lens designs.Item type:Item, Design of aspheric lens to collimate and uniform irradiance of a light source with Lambertian angular distribution - art. no. 63422F(2006) ;Cheng, Chieh-Jen ;Chern, Jyh-Long ;光電工程學系Department of PhotonicsA design of aspheric lens is proposed to collimate a light source of Lambertian angular distribution and generate homogenous irradiance. Two numerical solutions were calculated. One used even orders of general aspheres to describe the aspheric surfaces and the performance was evaluated by commercial optical software package Tracepro. Both of high numerical aperture (NA) of 0.79 and good RMS uniformity within 95% of designed area in the second surface of lens could be obtained. The reverse of this lens would be used in focusing and the simulated point spread function (PSF) is almost diffraction-limited. The other fitted both of aspheric surface with radial spline surface and the performance was evaluated by commercial optical software package OSLO. With the radial spline surface representation, the aspheric lens has a higher NA of 0.9; meanwhile, the uniformity was still good enough and PSF is also near diffraction-limited.Item type:Item, 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 PhotonicsLED 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.Item type:Item, Zoom lens design of mobilephone camera with global-explorer optimization - art. no. 66680P(2007) ;Hung, Chao-Yu ;Chern, Jyh-Long ;光電工程學系Department of PhotonicsUnlike the designs of common zoom lenses in literature, mobilephone applications demand an extremely short total track length (TTL), less around 10 mm. This short TTL request makes the zoom lens design of mobile phones unique. Also in viewing the cost advantage of CMOS sensor, we explore the mobilephone camera zoom lens with typical CMOS sensor format by global explorer (GE) optimization as well as the fundamental limitations. The basic lens forms for initial designs are deduced. Physically different merit functions have been developed to investigate how the best performance could be achieved. Furthermore, we also identify the improvements that could be achieved by GE optimization.