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Your search keyword '"Qin, Zong"' showing total 5 results
Start Over Author "Qin, Zong" Journal applied optics
5 results on '"Qin, Zong"'

4. Integral freeform illumination lens design of LED based pico-projector

Author

Zhao, Shuang, Wang, Kai, Chen, Fei, Qin, Zong, and Liu, Sheng

Subjects
Liquid crystals -- Research, Mathematical optimization -- Analysis, Polarization (Light) -- Influence
Abstract

In this paper, an illumination lens design for a LED-based pico-projector is presented. Different from the traditional illumination systems composed by lens group, the integral illumination lens consists of a total internal reflector (TIR) and a freeform surface. TIR acts as collimation lens and its top surface formed by a freeform surface reshapes the nonuniform circular light pattern generated by TIR to be rectangular and uniform. Diameter and height of the lens are 16 and 10 mm, respectively. An optimization method to deal with the problem of extended light source is also presented in detail in this paper. According to the simulation results of the final optimized lens, 77% (neglecting the effect of polarization) of the power of light source is collected on liquid crystal on silicon panel with a 16?9 ratio and illumination uniformity achieves 92%.

Published
2013

5. Digital halftoning method with simultaneously optimized perceptual image quality and drive current for multi-tonal electrophoretic displays

Author

Qin, Zong, Wang, Hsin-I, Chen, Zi-Yu, Chen, Chun-Ho, Tien, Pei-Lin, Liu, Mei-Hwa, Liu, Shu-Cheng, Hung, Chi-Mao, Tsai, Chuan-Chuan, and Huang, Yi-Pai

Abstract

While using digital halftoning to achieve multi-tones in a 1 bit electrophoretic display (EPD), e.g., a three-pigment chromatic EPD, the drive current is significantly increased because of frequently reversed pixel values. Aimed at this issue, this study first establishes a model that can accurately predict the drive current from image content. Next, based on the direct binary search method, a new halftoning method is proposed by constructing a combined merit function that incorporates both the perceptual image quality and the drive current. As a result, in experiments using a 13.5 in. three-pigment EPD and several test images, compared with the well-developed error-diffusion method, the proposed method produces little image quality degradation, whereas the drive current increase with respect to the minimum current of the EPD is reduced from 71.8 to 33.0 mA, for a significant reduction of 54.0%.

Published
2020

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