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Phosphor-in-glass (PiG) patterned with micro-cone arrays, which can be fabricated by photolithography and inductively coupled plasma dry etching methods, is proposed to enhance light extraction efficiency (LEE) of white light-emitting diodes (LEDs) package. The effects of microstructure arrays on the LEE of LEDs are investigated by optical simulations and experiments. Optical performance of the LED...
We directly demonstrate a dielectric optical magnetic mirror using phase-locked mid-infrared time-domain spectroscopy. This magnetic mirror is formed by micron-sized cubes of tellurium fabricated on a dielectric substrate.
Angular color uniformity (ACU) of a king of popular remote phosphor coating LED packaging with spherical phosphor shape with uniform thickness was invested by the Monte Carlo ray tracing method. The simulation results indicate the yellowish ring can't be avoided under uniform phosphor thickness in angular range of 0°–180°. The optimized phosphor geometry was proposed whose thickness gradually reduces...
In keeping with consumer preferences for ever more high-performance products, a requirement exists for precise autofocusing microscope systems for the inspection processes in mass production lines. Accordingly, a precise autofocusing microscope is proposed based on the reduction of the geometrical fluctuations of a laser light source, in which, the geometrical fluctuations of the laser light source...
In this study, we firstly analyse the requirements both in optical and thermal fields in theory. With the results of theoretical analysis, we design the application specific light emitting diode (LED) packaging (ASLP) with optimized structure parameters and appropriate packaging materials. According to this design, several samples are made and tested. The test results show that the LED packaging can...
YAG: Ce phosphor is widely used in LED industry with powder form to mix with silicone. The phosphor particle size is important by affecting optical performance of white LEDs in terms of luminous flux and angular color uniformity. This paper constructed a white LED optical model referring to CREE white LEDs. The optical simulation reveals that 2 μm phosphor particle presents the lowest luminous flux...
In keeping with consumer preferences for ever more high-performance products, a requirement exists for precise and fast auto-focusing microscope systems for the inspection processes in mass production lines. Accordingly, the present study proposes a precise and fast laser-based auto-focusing microscope system in which an auto-focusing capability is achieved by using a position feedback signal from...
A dual-confocal auto-focus sensing module for measuring defocusing positions of specimens in laser machining systems or inspecting devices is proposed. This sensing module can improve the detecting accuracy by analyzing and fitting signals from the difference between the dual optical paths, and miniaturize the optical apparatus with the superior integrated optical design. This auto-focusing module...
Low light extraction efficiency (LEE) is one of the most challenging points for light-emitting diode (LED) array packaging. Analysis of LEE enhancement of LED array packaging with micro-structures on packaging silicone is presented. To obtain high LEE, micro-structures including inversed cone, inversed frustum of a pyramid (FP) and V-groove are introduced. Two types of LED chips consisting of conventional...
LED's luminous efficiency increases rapidly in recent years, many novel illumination applications with LEDs are emerging. Based on the analysis of LED's characteristics, our optimization scheme and design methods for LED taxiway lamps are proposed. A novel LED lamp using in navigation of the taxiway of the airport is designed as an example. The simulation results demonstrate that the light utilization...
We report on the controllable band-gap structure and nonlinear localized states of light in two-dimensional photonic superlattices. Bright gap solitons and vortex solitons residing in an additional mini-gap due to the extra periodicity are presented.
The color uniformity is a critical index in the evaluation of high quality white light emitting diodes (LEDs). The main factor affecting the color distribution is the state of the phosphor. The secondary factor is the optical structure. This paper analyzes two parameters of the phosphor layer (thickness and concentration) and six optical structures. Results indicate that the structures with reflector...
Optical analysis is critical to the evaluation of an LED MR16 lamp, especially when the lamp is still in its early stage of development and applications and when optimization is needed for making use of unique characteristics of LEDs. In this study, optical research of a 3W LED MR16 lamp was conducted. The experimental results demonstrated that the LED MR16 lamppsilas angle of full width at half intensity...
The state of phosphor will greatly influence the packaging performance such as luminous efficiency, quality of white light and color uniformity. The analysis presents that the small variations of thickness and concentration could significantly influence the light extraction efficiency and the correlated color temperature (CCT). With the increase of thickness and concentration, the light extraction...
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