Kun Shan University

About: Kun Shan University is a education organization based out in Tainan City, Taiwan. It is known for research contribution in the topics: Heat transfer & Thin film. The organization has 1992 authors who have published 2928 publications receiving 45685 citations. The organization is also known as: Kūnshān Kējì Dàxué.

Spatially tunable photonic bandgap of wide spectral range and lasing emission based on a blue phase wedge cell.

Abstract: This study demonstrates for the first time a continuously tunable photonic bandgap (PBG) of wide spectral range based on a blue phase (BP) wedge cell. A continuously shifting PBG of the BP wedge cell occurs due to the thickness gradient of the wedge cell at a fixed temperature. The wedge cell provides a gradient of boundary force on the LCs and thus forms a distribution of BP crystal structure with a gradient lattice. Additionally, a spatially tunable lasing emission based on a dye-doped BP (DDBP) wedge cell is also demonstrated. The tunable band of the PBG and lasing emission is about 130 nm and 70 nm, respectively, which tuning spectral ranges are significantly wider than those of CLC and DDCLC wedge cells, respectively. Such a BP device has a significant potential in applications of tunable photonic devices and displays.

Polarization characteristics of diffracted beams from twisted nematic gratings fabricated by the photoalignment effect in dye-doped liquid-crystal films

Abstract: The polarization characteristics of diffracted beams from twisted nematic (TN) gratings are investigated. The TN grating is fabricated by exploiting the photoalignment effect in a dye-doped homogeneous liquid-crystal film. Experimental results indicate that the irradiation of an azo-dye-doped liquid-crystal film with appropriate light can induce dye adsorption on a glass substrate. The adsorbed dyes then reorient the liquid-crystal director perpendicular to the pump-beam polarization. The polarizations of the diffracted beams from such a TN grating are systematically studied. The experimental results correlate well with theory. Additionally, the TN grating can be used as a polarization beam splitter.

Robust tracking control for a class of uncertain electrically driven robots

Abstract: The problem of designing robust tracking controls for a large class of robots actuated by brushed direct current motors is addressed. This class of electrically driven robots can be perturbed by plant uncertainties, unmodelled time-varying perturbations and external disturbances. Adaptive neural network (or fuzzy) systems are employed to approximate the behaviours of uncertain dynamics, and the variable structure system control algorithm is used to efficiently eliminate the effect of both the approximation error and the time-varying perturbation. Consequently, a hybrid robust adaptive dynamic feedback tracking controller is developed such that all the states and signals of the closed-loop system are bounded and the asymptotic bound on the trajectory tracking error can be made arbitrarily small. Finally, simulation examples are presented to demonstrate the effectiveness and the tracking performance of the proposed control algorithm.

Optical Design of LCOS Optical Engine and Optimization With Genetic Algorithm

Abstract: This paper demonstrates an optical design of miniature of LCOS optical engine and optics with white light-emitting diode (LED) and the most importantly, proposes a new optimization method for non-image optics via Genetic Algorithm (GA) written in Optical Software ASAP, in order to achieve best performance for light efficiency and uniformity. Thanks to the development of modern digital equipment, optimization work for non-image optics plays a role in modern optical engineering. So far Least Damping Square, Taguchi Fuzzy, and simulation annealing methods have been introduced and some of them has been applied to many items of commercial simulation software. However, GA is first introduced in this paper for non-image optical design and optimization, although it has been for many years been used as effective optimization method in image optics; In this paper, GAs are written in the form of macro language from ASAP. During the design process, we used one OPTEK Technology OVS3WBCR44 LED as the light source of the general projection display. Because of the extensiveness of the LEDs, the collection efficiency within the desired acceptance angle was not expected to be high. Due to the particular acceptance angle (cone), we needed a condenser lens system, which satisfied the light small angle incident to 0.59-in liquid-crystal-on-silicon (LCOS) pixels. The optical engine in this paper is designed for a compact LCOS projector with a white LED light source and the employment of an LCOS panel has been reduced to one piece in order to get the best volumetric size. Optical design specification is mainly for an 11" projected screen, whose objective distance is close to 420 mm with fixed focal lens. GA methods are applied in this research in order to achieve maximum brightness and uniformity. Compared to traditional optimization methods, such as Least Damping Square, the GA used in this research gives reasonably good results.

Design of a Triple-Passband Microstrip Bandpass Filter with Compact Size

Abstract: This paper presents the triplepassband microstrip bandpass filter (BPF) with compact size Two sets of the coupled asymmetric stepped impedance resonators (SIRs) and uniform impedance resonators (UIRs) are arranged for generating the triple-passband properties It is convenient to control the triple-passband properties by tuning the impedance ratio (K) and length ratio (γ) of the asymmetric SIRs The UIRs are also employed to enhance the coupling between the coupled resonators at 3rd passband The filter is designed at 24/52/82 GHz and achieves nearly 50% circuit size reduction compared with the previous works This study provides a simple method to design a triple-passband filter with compact circuit size Experimental verification is provided, and good agreement has been found between simulation and measurement