scholarly journals Luminous Intensity Field Optimization for Antiglare LED Desk Lamp without Second Optical Element

2020 ◽  
Vol 10 (7) ◽  
pp. 2607 ◽  
Author(s):  
Zhi-Ting Ye ◽  
Chieh Chang ◽  
Mao-Chieh Juan ◽  
Kuei-Jung Chen
Keyword(s):  
Light Emitting Diode ◽  
Optical Element ◽  
Spatial Effect ◽  
Experimental Results ◽  
Luminous Intensity ◽  
Beam Angle ◽  
Intensity Curve ◽  
Light Emitting ◽  
Human Eye ◽  
Intensity Field

This study proposes a model of a light module with an optimized luminous intensity field for realizing an antiglare light-emitting diode (LED) desk lamp without a second optical element. We simulated different luminous intensity field profiles to analyze the unified glare rating (UGR) and illumination uniformity performance of a desk lamp. The spatial effect of UGR and the illumination uniformity affect eye comfort. The light module was set to different beam angles without a second optical element, louver structure, and reflective element on the luminaire to compare different UGRs and uniformity values for evaluating human eye comfort. The simulation and experimental results indicated that the luminous intensity curve for a beam angle of 90° achieved an illumination uniformity of 80% and a UGR of 18.1 at a height of 45 cm, thus realizing a human-friendly antiglare desk lamp.

The effectiveness of light-emitting diode lighting for providing circadian stimulus in office spaces while minimizing energy use

2019 ◽  
Vol 52 (2) ◽  
pp. 167-188 ◽  
Author(s):  
C Jarboe ◽  
J Snyder ◽  
MG Figueiro
Keyword(s):  
Energy Use ◽  
Spectral Power ◽  
Light Emitting Diode ◽  
Visual Performance ◽  
Luminous Intensity ◽  
Light Emitting ◽  
Lighting Conditions ◽  
Office Space ◽  
Discomfort Glare ◽  
Architectural Lighting

Architectural lighting has traditionally addressed visual performance and horizontal illuminance on the work plane, later focussing on energy efficiency, while only recently paying particular regard to human health outcomes. The present study evaluated the effectiveness of several light-emitting diode lighting strategies for delivering circadian stimulus to occupants of a typical office space while minimizing energy use. The study employed photometric simulations in a typical open-office space, delivering a criterion circadian stimulus of 0.3 to calculation points modelled at the simulated occupants’ eye level. Six luminaire types, two luminous intensity distributions, six spectral power distributions and two horizontal illuminances were evaluated, resulting in 144 unique lighting conditions. Additionally, the study calculated the discomfort glare for selected luminaires with the highest total lumen output, smallest aperture and direct-only luminous intensity distributions at the higher of the two horizontal illuminances (500 lx). The most impactful strategy involved supplementing common overhead lighting with a desktop luminaire delivering light directly to the simulated office occupants’ eyes, which provided greater circadian stimulus and used less energy than overhead luminaires that were capable of delivering the criterion circadian stimulus of 0.3.

scholarly journals ADVANCED SAFETY SYSTEM FOR AUTOMOBILES THROUGH VEHICLE TO VEHICLE COMMUNICATION USING LIFI

2020 ◽  
Vol 6 (10) ◽  
pp. 31-36
Author(s):  
Sheik Shameem Mohamed Yousuff Raja ◽  
Nithiish Chellaiah ◽  
Goharnath Murali ◽  
Niresh J
Keyword(s):  
Light Emitting Diode ◽  
Control Unit ◽  
Vehicle Control ◽  
Safety System ◽  
Speed Limit ◽  
Light Emitting ◽  
Led Light ◽  
Human Eye ◽  
Vehicle Communication ◽  
Vehicle To Vehicle

The new vehicle execution has been persistently improved and the examination resultsidentifying with the wellbeing of vehicle driving have additionally been consistently announcedand illustrated, it is attempting to discover an equalization point between the advancement ofvehicle speed limit and the assurance of driver's security. Li-Fi is a VLC, visible lightcommunication innovation that manages move of information through enlightenment byremoving fibre from optics by sending information through a LED light that fluctuates in theforce quicker than a human eye can pursue. In this undertaking we attempt to build up aframework to give the before mishap data to the vehicle control unit with the goal that itempowers the vehicle to anticipate the occurrence of mishap. Vehicle to vehicle correspondenceis the best arrangement that has been utilized so as to decrease vehicles' mishaps. The proposedutilization of Li-Fi innovation in this task involves the light emitting diode (LED) bulbs asmethods for network by sending information through light range as an optical remote vehiclefor signal engendering. Truth be told, the use of LED dispenses with the need of complex remotesystems and conventions.

scholarly journals Joule Thief Sebagai Boost Converter Daya LED Menggunakan Sel Volta Berbasis Air Laut

2018 ◽  
Vol 4 (2) ◽  
pp. 52
Author(s):  
Anwar Mujadin ◽  
Suci Rahmatia
Keyword(s):  
Electromagnetic Field ◽  
Electric Current ◽  
Light Emitting Diode ◽  
Boost Converter ◽  
Experimental Results ◽  
Power Transfer ◽  
Light Emitting ◽  
Electric Circuits ◽  
Led Lights

<p><em>Abstrak – </em><strong>Joule-Thief adalah salah satu rangkaian listrik  untuk konservasi  energi dengan menggunakan teknis medan elektromagnetik arus transien pada sebuah coil. Sirkuit ini dioperasikan menggunakan  sebuah MOSFET sebagai saklar untuk meregenerasi  tegangan dan arus listrik dalam satuan waktu kemudian disalurkan pada beban light emitting diode (LED). Dari hasil eksperimental,  sel volta berbasis air laut dengan tegangan jepit 0.8V mampu mengaktifkan lampu LED dengan konfigurasi rangkaian serial. Hasilnya menunjukkan bahwa power transfer maksimum dari sirkuit Joule-thief sangat efektif sebagai pemasok daya beban 60 LED.</strong></p><p><strong> </strong></p><p><strong><em>Kata Kunci </em></strong><em>- <strong> </strong>Joule Thief, Boost Converter Daya LED, Sel Volta Berbasis Air Laut<strong></strong></em></p><p><em> </em></p><p><em>Abstract –</em> <strong>Joule-Thief is one of the electric circuits for conservation energy by using electromagnetic field trancient current in a coil. This circuit is operated using a MOSFET as a switch to regenerating the voltage and current flowing along the coil. The electric current accumulates in the coil then in unity of time will be supplied to the light emitting diode (LED) load. From experimental results, water sea voltaic cells based with 0.8V clamp voltage are able to activate LED lights in serial circuit configurations. The results shown that power transfer joule-thief circuit is very effective capable of supplying LED up to 60 LEDs.</strong></p><p><strong> </strong></p><p><strong><em>Keywords </em></strong><em>- Joule Thief, </em><em>Boost Converter Power LED</em><em>, </em><em>Sea-Based Voltaic Cells</em><em></em></p>

Freeform lens design for light-emitting diode uniform illumination by using a method of source–target luminous intensity mapping

2015 ◽  
Vol 54 (28) ◽  
pp. E146 ◽  
Author(s):  
Jin-Jia Chen ◽  
Ze-Yu Huang ◽  
Te-Shu Liu ◽  
Ming-Da Tsai ◽  
Kuang-Lung Huang
Keyword(s):  
Light Emitting Diode ◽  
Luminous Intensity ◽  
Lens Design ◽  
Uniform Illumination ◽  
Light Emitting ◽  
Intensity Mapping ◽  
Freeform Lens

Luminous intensity correction method for misalignment-induced measurement error of light-emitting diode arrays

2018 ◽  
Vol 51 (3) ◽  
pp. 432-446
Author(s):  
HY Wu ◽  
HB Cheng ◽  
YP Feng ◽  
X Chen
Keyword(s):  
Intensity Distribution ◽  
Measurement Errors ◽  
Light Emitting Diode ◽  
Correction Method ◽  
Luminous Intensity ◽  
Practical Application ◽  
Light Emitting ◽  
Physical Measurements ◽  
Test Distance ◽  
Operating Methods

To eliminate axial misalignment-induced measurement errors of discrete light-emitting diode arrays in the far-field condition, a robust and effective method for correcting the measured luminous intensity distribution is proposed. The precision of the correction can be determined beforehand by setting a criterion which can also be used to determine the required test distance. To validate the feasibility and practicability of the proposed approach, numerical simulations of light-emitting diode arrays with three kinds of typical luminous intensity distributions were performed. In addition, the test distances as a function of the light-emitting diode luminous intensity distribution, packing density and dimensions under translational misalignment were analysed. Some beneficial operating methods and rules for practical application are summarised. Finally, physical measurements of several experimental examples were collected. The correction results agreed with the desired data and again proved the utility of the presented method.

Inspection of electronics packages using the efficient perception technique

2004 ◽  
Vol 21 (2) ◽  
pp. 41-44 ◽  
Author(s):  
Z.W. Zhong ◽  
Y. Jiang
Keyword(s):  
Visual Inspection ◽  
Light Emitting Diode ◽  
Experimental Results ◽  
Inspection System ◽  
Gray Level ◽  
Light Emitting ◽  
Led Lighting ◽  
Electronics Packages ◽  
Sparrow Model

When engineers choose and arrange proper lighting sources for an inspection system, many of them rely on their own experience or guesswork without any guidance of theories. This paper discusses the efficient perception technique, i.e. the Torrance‐Sparrow model and its application to the selection and configuration of light emitting diode (LED) lighting sources for a package visual inspection system. Inspection of several typical package samples has been evaluated. The image changes of the sample packages are explained using the Torrance‐Sparrow model. The experimental results with the actual gray level values of the images are compared.

Compact collimators designed with point approximation for light-emitting diodes

2016 ◽  
Vol 50 (2) ◽  
pp. 303-315
Author(s):  
T Luo ◽  
G Wang
Keyword(s):  
Design Method ◽  
Light Emitting Diode ◽  
Lens Design ◽  
Beam Angle ◽  
Optical Efficiency ◽  
Light Emitting ◽  
Chip Size ◽  
Practical Performance ◽  
Freeform Lens ◽  
Collimating Lens

We present a novel freeform lens design method for application to light-emitting diode collimating illumination. The lens is designed with a point-source assumption to form compact collimators. The method is derived from a basic geometric-optics analysis and the associated construction approach. By using this method, a compact collimating lenses with an aspect ratio = 0.181 is developed. With optimization of initial parameters, a highly collimating lens for a Cree XP-E LED (chip size: 1.2 mm × 1.2 mm) with an optical efficiency of 88.5% under a beam angle of ± 1.9° is constructed by simulation. To verify the practical performance of the lens, a prototype of the collimator lens is also made. This has light distribution compatible with the simulation results.

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