scholarly journals Cavity-excited Huygens’ metasurface antennas for near-unity aperture illumination efficiency from arbitrarily large apertures

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Ariel Epstein ◽  
Joseph P. S. Wong ◽  
George V. Eleftheriades
Keyword(s):  
Illumination Efficiency

scholarly journals Beam Pre-Shaping Methods Using Lenslet Arrays for Area-Based High-Resolution Vehicle Headlamp Systems

2020 ◽  
Vol 10 (13) ◽  
pp. 4569
Author(s):  
Yang Li ◽  
Marvin Knöchelmann ◽  
Roland Lachmayer
Keyword(s):  
High Resolution ◽  
Design Principles ◽  
Beam Shaping ◽  
Light Distribution ◽  
Distribution Area ◽  
New Methods ◽  
Lenslet Array ◽  
And Performance ◽  
Illumination Efficiency

High-resolution light distributions are lately in demand for vehicle headlamp systems as an innovative lighting approach. This lighting approach can realize functionalities, such as precise glare avoidance and on-road projection, which are useful for improving traffic comfort and safety. For achieving the required high-resolution light distribution, area-based projection technologies, such as DMD, LCD, and LCoS, are considered to be integrated into such headlamps. These projection devices demand rectangular illumination areas with specific light distributions to fulfill the requirements for illumination efficiency and performance in headlamp systems. Lenslet arrays, based on the principle of Köhler illumination, can effectively homogenize the light and shape it into rectangular shapes simultaneously. Such components are widely used in projection applications. However, they also show functional potentialities to be applied in high-resolution headlamps. This paper explains the design principles and methods of lenslet arrays for beam pre-shaping in headlamp systems. It validates the homogenization using a self-designed and manufactured lenslet array in a demonstrator in the first place. Afterward, this paper introduces two new methods for the centralized beam shaping required by some headlamps. These methods are validated by optical simulations.

On the Efficiency of Lighting by LEDs in Visual Work

2018 ◽  
pp. 81-87 ◽  
Author(s):  
Svetlana A. Amelkina ◽  
Olga E. Zheleznikova ◽  
Lyudmila V. Sinitsyna
Keyword(s):  
Human Body ◽  
Practical Importance ◽  
Negative Influence ◽  
Visual Fatigue ◽  
Working Capacity ◽  
Functional Indices ◽  
Illumination Efficiency ◽  
Reversible Nature ◽  
Visual Organ

It is experimentally found that LEDs illumination does not cause a negative influence on visual organs and human body as a whole. It is shown that changes of visual organ functional indices for visual operations are within the correspondent boundaries of physiological fluctuations and have a reversible nature. Integral indices of LEDs illumination efficiency from visual working capacity and visual fatigue degree are estimated. A practical importance of the obtained results is shown.

Illumination efficiency of a shaped Cassegrain system

1970 ◽  
Vol 18 (3) ◽  
pp. 411-412 ◽  
Author(s):  
B. Rao ◽  
S. Chen
Keyword(s):  
Illumination Efficiency

Heat Transfer Measurements of Compact High Power LED Illumination Cooled by Different Fluids

2010 ◽  
Author(s):  
Rong-Yuan Jou
Keyword(s):  
High Power ◽  
Silicone Oil ◽  
Thermal Imager ◽  
Liquid Cooling ◽  
Atmospheric Air ◽  
High Power Led ◽  
In Series ◽  
Measurement Methodology ◽  
Illumination Efficiency ◽  
Resistance Equation

The generated heats of high-power LED illumination will increase the LEDs’ working temperatures which may degrading the illumination efficiency and lifetimes of LED devices. In this study, the liquid cooling of directly immersed LEDs in different ambient of air or liquids is investigated by the experimental measurement methodology. For LEDs which are operated in series, the generated heats are dissipated into and stored in ambient fluids, then, the casing of lamp (usually acted as a heat sink structure) further conduct these heats and dissipate it into atmospheric air finally. In the experiments, different powers are sequentially input into the LEDs and different fluids, including air, silicone oil, and FC-40, respectively, are filled to cool the LEDs which are directly immersed in these fluids. Temperatures are measured by thermocouples and the IR thermal imager, respectively. Fluid-to-air thermal resistances and fluid temperatures are estimated by a proposed resistance equation. The calculated temperatures are within 10% of error as compared to experimental results. This resistance model is a very good way to quickly examine the fluid-to-air resistances if we want to design the liquid-cooled package of LED illumination.

DC Current-Induced Rollover of Illumination Efficiency of GaN-Based Power LEDs

2007 ◽  
Vol 19 (24) ◽  
pp. 2000-2002 ◽  
Author(s):  
Michael P. Liao
Keyword(s):  
Dc Current ◽  
Illumination Efficiency

scholarly journals High-efficiency, large-area lattice light-sheet generation by dielectric metasurfaces

Nanophotonics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 4043-4051
Author(s):  
Fenghua Shi ◽  
Jing Wen ◽  
Dangyuan Lei
Keyword(s):  
Spatial Resolution ◽  
Temporal Resolution ◽  
High Efficiency ◽  
Numerical Aperture ◽  
Light Sheet ◽  
Field Of View ◽  
Objective Lens ◽  
High Temporal Resolution ◽  
Light Sheet Microscopy ◽  
Illumination Efficiency

AbstractLattice light-sheet microscopy (LLSM) was developed for long-term live-cell imaging with ultra-fine three-dimensional (3D) spatial resolution, high temporal resolution, and low photo-toxicity by illuminating the sample with a thin lattice-like light-sheet. Currently available schemes for generating thin lattice light-sheets often require complex optical designs. Meanwhile, limited by the bulky objective lens and optical components, the light throughput of existing LLSM systems is rather low. To circumvent the above problems, we utilize a dielectric metasurface of a single footprint to replace the conventional illumination modules used in the conventional LLSM and generate a lattice light-sheet with a ~3-fold broader illumination area and a significantly leveraged illumination efficiency, which consequently leads to a larger field of view with a higher temporal resolution at no extra cost of the spatial resolution. We demonstrate that the metasurface can manipulate spatial frequencies of an input laser beam in orthogonal directions independently to break the trade-off between the field of view and illumination efficiency of the lattice light-sheet. Compared to the conventional LLSM, our metasurface module serving as an ultra-compact illumination component for LLSM at an ease will potentially enable a finer spatial resolution with a larger numerical-aperture detection objective lens.

High Illumination Efficiency Linear Light Source Using Light Emitting Diodes

2007 ◽  
Vol 46 (2) ◽  
pp. 563-565 ◽  
Author(s):  
Di Feng ◽  
Jaehwan Yoo ◽  
Kaname Nagatani ◽  
Wookyu Kim ◽  
HyeongChae Kim
Keyword(s):  
Light Source ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
High Illumination ◽  
Illumination Efficiency
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