Search

The major factors associated with the manufactured structures and photon emission intensity distribution must be accurately identified for the complicated optical design parameters associated with micro-LED pixels. This study presents the methodologies and reveals the sequential calculating protocol in each layer for pixel-level optical simulations, based on which the boundary condition errors associated with common optical simulations can be corrected. Moreover, the optical effect on each epitaxial layer of the micro-LED design is revealed, and the rationality of the setting of the finite-radius receiver with a pseudo-extended substrate material is also explained with respect to the intrinsic and extrinsic pixel-intensity distribution properties. Finally, the design of experiments DOE L18 orthogonal array table is demonstrated by the Taguchi method to explore the principal factors for the parameter design of the micro-LED layers. The results indicate that the sapphire thickness, the P-GaN layer, the buffer layers, and an additional substrate plate are the four significant factors that primarily influence the luminous power and the corresponding uniformity on the exit pupil of micro-LEDs. Based on the luminous power uniformity, the signal-to-noise ratio in the sapphire thickness is 16.9, and the extended substrate plate is 9.8, which is ∼10 times > the interaction design parameter, such as the etching angle and reflective index of the extended substrate of the micro-LED pixel. These specific design factors can be the major optimization parameters for cost control and performance improvement.

The optimal use of energy resources is the central dogma for green technology and bio-optics. Reflectors provide a simple and fundamental structure for energy transport from a light emitting diode (LED) chip, and an appropriately designed reflector can reduce the fabrication cost of secondary optics for the LED. This paper demonstrates the role of three proposed reflector geometric factors in the two performance metrics - uniformity and collected energy (power), for designing LED reflectors. Through canonical factor analysis, a linear structure equation for LED reflector is suggested, and the methodology for designing the optimal shape is discussed. In addition, a generalized factor and a synthesis response are proposed for a more comprehensive investigation of optical performance. Results indicate a key parameter for balancing the optical performance, and the effects of various parameters and the trade-offs are revealed. [ABSTRACT FROM AUTHOR]

The article presents a study which discusses the solid-state light sources model of phosphor-based light-emitting diode (LED). The study uses the ray tracing procedure along with the suitable LED emission apodization pattern checked through the signal-to-noise ratio examination on the illuminating plane and color coordinates determined by energy ratios. The study revealed that the illumination and color patterns can be restored, however, several factor influence the color distribution of LED.

A conference paper about the uniformity improvement of the light emitting diode (LED) illumination system is presented. It compares the three different types of lens such as the hemispheroid, unoptimized and the lens after optimization. It discusses the non-spherical lens design approach used to optimize and improve the extraction energy and the spatial uniformity of the LED illumination system. It reveals that the new developed lens can improve uniformity from 28.4% to 64%.

In this study, we aimed to validate a novel light field virtual reality (LFVR) system for estimating refractive errors in the human eye. Fifty participants with an average age of 22.12 ± 2.2 years (range 20–30 years) were enrolled. The present study compared spherical equivalent (SE) and focal line measurements (F1 and F2) obtained by the LFVR system with those obtained by established methods, including closed-field and open-field autorefractors, retinoscopy, and subjective refraction. The results showed substantial agreement between the LFVR system and the traditional methods, with intraclass correlation coefficients (ICC) for SE ranging from 82.7% to 86.7% (p < 0.01), and for F1 and F2 from 80.7% to 86.4% (p < 0.01). Intra-repeatability for F1 and F2 demonstrated strong agreement, with ICC values of 88.8% and 97.5%, respectively. These findings suggest that the LFVR system holds potential as a primary tool for refractive error measurement in optical care, offering high agreement and repeatability compared to conventional methods. [ABSTRACT FROM AUTHOR]

In Taiwan, issues in technology education (TE), such as indeterminate core mission and unclear role, could be addressed through an objective knowledge map of research to discern directions of development and prospects. This study explores sub-fields, genres, characteristics, and trends in TE research in Chinese and English over 24 years through bibliometric co-citation analysis using two databases: Web of Science and Airiti Library. As per the findings: (1) TE research has been progressing slowly in Taiwan, while it is developing rapidly elsewhere; Disciplines integrated with TE include education and educational research, engineering, computer science, social sciences, and medicine; (2) Research topics have evolved from industrial arts, technical and vocational education, technological literacy education, and curriculum development, to pedagogical skills of teachers of technology; Other countries focus on "professional development of technology teachers," while Taiwan emphasizes "curriculum and teaching materials;" (3) Clusters from different periods are complementary, and research topics and fronts reflect continuity. (4) "Assessment," as a research dimension, has received insufficient attention. Insights into the evolution of research topics and research fronts are offered for technology educators. [ABSTRACT FROM AUTHOR]

Although apodization patterns have been adopted for the analysis of sputtering sources, the analytical solutions for the film thickness equations are yet limited to only simple conditions. Empirical formulations for thin film sputtering lacking the flexibility in dealing with multi-substrate conditions, a suitable cost-effective procedure is required to estimate the film thickness distribution. This study reports a cross-discipline simulation program, which is based on discrete particle Monte-Carlo methods and has been successfully applied to a non-imaging design to solve problems associated with sputtering uniformity. Robustness of the present method is first proved by comparing it with a typical analytical solution. Further, this report also investigates the overall all effects cause by the sizes of the deposited substrate, such that the determination of the distance between the target surface and the apodization index can be complete. This verifies the capability of the proposed method for solving the sputtering film thickness problems. The benefit is that an optical thin film engineer can, using the same optical software, design a specific optical component and consider the possible coating qualities with thickness tolerance, during the design stage. [ABSTRACT FROM AUTHOR]

This report proposes a graphical-like approach for simulating the Hamiltonian of the t-J model. The two spin states are modeled by the two emitting layer, the kinematics of the electrons and the causalities between the operators are satisfied through the event cone. Operators and the event cone are integrated together, and the results indicate that this approach can provide information during the evolution of the t-J model. In addition, parameters that can be accessed by this approach are consistent with general requirements on values of t and J in the t-J model. Furthermore, our approach also includes the solution with vanishing hopping amplitude (tij = 0) and the H∞ solution. [ABSTRACT FROM AUTHOR]

-doped and -doped nanowires have been prepared to compare the substitution effect on the microstructural and magnetic properties. The XRD patterns of both compositions with single diffraction peak (002) show the same wurtzite hexagonal structure. The growth rate of the nanowires were enhanced by doping, which were different from the suppression of growth rate by doping. Room temperature ferromagnetism is observed for all , -doped and -doped nanowires. The saturation magnetizations are 0.102, 0.232 and 0.04 emu/g for , -doped and -doped nanowires, respectively. The results showed that the ferromagnetism is restrained by doping, but enhanced by the doping. [ABSTRACT FROM AUTHOR]

Fresnel-like prism arrays are designed using geometric ray optics and fabricated on a curved surface according to specific focal length requirements. In this study, the tolerance of Fresnel-like prism structures on arbitrary surfaces was investigated. Compact equations (iterative and non-iterative) based on analytical formulation can be helpful in exploring the sensitivity associated with the fabrication of Fresnel-like structures. The curved surface in this study revealed a linear relationship between maximum angular tolerance and the angle of incident rays. An understanding of such linearity is a key issue in the fabrication of lenses as well as in the sensitivity formulae used for optical structures in the development of next-generation optics. [ABSTRACT FROM AUTHOR]

SUMMARY The finite element method with linear elastic assumption for predicting the intraocular pressure (IOP) readings after reshaping of the corneal structure is demonstrated in the present study. Twelve effective eye measurements in seven subjects were examined using the TOPCON LX-10, a noncontact intraocular pressure measurement technique, before and after laser-assisted in situ Keratomileusis surgery. A linear elastic model was introduced to reduce possible errors from a complicated anisotropic model with uncertain tissue parameters. Linear relationship between the simplified removal depth of laser-assisted in situ Keratomileusis and predicted IOP was expected, and the comparisons between measurements and the predicted model were made. The results indicated that the expected IOP readings are close to the measurement IOP values, while larger errors occur at smaller IOP conditions. In conclusion, the linear elastic finite element approach can already reveal parameters that influence measurement data the most, and the interaction between parameters was higher than we had expected. This helps us to build the confidence on implementing the anisotropic model.Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Liquid crystals have been recognized as practical adaptive optical components for imaging and nonimaging applications. We have studied a liquid crystal lens without power modulation, as distinct from a focus modulating lens, and have simulated the effects of transient birefringence on the energy distribution on the focal plane. Our results indicate that owing to the particular transient spreading energy patterns on the focal plane, a focusing reversal phenomenon takes place during the operation of this lens, and the characteristic of the modulation transfer function (MTF) of this device indicates that this lens can serve as a spatial frequency filter. [ABSTRACT FROM AUTHOR]