scholarly journals Light Source for 21st Century: LED (Light Emitting Diode)

2005 ◽  
Vol 81 (12) ◽  
pp. 1010-1011
Author(s):  
Yosuke NISHIKAGE
Keyword(s):  
Light Source ◽  
21St Century ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Led Light

1.331μm Narrow-Bandwidth Light Source Based on Polymer Micro-Blazed Grating

2008 ◽  
Author(s):  
Hairong Wang ◽  
Xianni Gao ◽  
Guoliang Sun ◽  
Yulong Zhao ◽  
Zhuangde Jiang
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Diffraction Order ◽  
Blazed Grating ◽  
Light Emitting ◽  
Led Light ◽  
Narrow Bandwidth ◽  
Narrow Width ◽  
The Cost

In order to detect methane (CH4) accurately and reliably, this paper presents a sensor which consists of infrared diode, fixtures, blazed grating, to realize the extremely narrow-bandwidth light at wavelength of 1.331μm. Based on factors such as compatibility with the transmission characteristics of silica fiber and the cost, a LED (light-emitting diode) with center wavelength of 1.3μm is selected. The LED light is modulated as the parallel light beam. As the light is incident in a micro-blazed grating with certain angle, by diffraction and interference, the light will output the maximum light intensity of its diffraction order at 1.331 μm, which just is an absorption peak of CH4. Micro-blazed grating applied here is low cost and easy replication by various ways, which makes extreme narrow width wavelength possible. Simulation and analysis indicate the designed prototype can output 1.331μm with bandwidth from 1.32907μm to 1.332495μm. With the light source basing on light dividing system, more reliable and higher sensitive measurement of the dangerous gases such as methane and carbon monoxide (CO) can be realized.

Effects of light source spectrum and background colour on the perception of paintings

2019 ◽  
Vol 52 (1) ◽  
pp. 36-63
Author(s):  
L Bellia ◽  
F Fragliasso ◽  
E Stefanizzi
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Source Spectrum ◽  
Light Emitting ◽  
Colour Temperature ◽  
Test Room ◽  
Led Light ◽  
Lighting Conditions ◽  
Set Up ◽  
Effect Of Light

This paper presents an experiment on the effect of light on the perception of paintings. The experiment was performed in a test-room where a typical museum exhibition set-up was simulated. Two different paintings were shown to 44 participants, under different light scenes obtained by using tuneable LED (Light Emitting Diode) wallwashers. To set the light scenes, the following parameters were modified: correlated colour temperature of the lighting, illuminance on the painting and the colour of the background wall. Participants answered a questionnaire to assess the perception of the paintings’ colours, the lighting conditions and the pleasantness of the exhibition set-up. The results demonstrated that illuminance is the parameter mainly affecting perception, for both paintings. However, correlated colour temperature and wall colour, as well as the combination of the three different considered parameters, can more or less influence perception depending on the chromatic composition of the painting.

scholarly journals Polymerization quality testing of composite resins cured by led light source

2003 ◽  
Vol 50 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Larisa Blazic ◽  
Slavoljub Zivkovic ◽  
Dejan Pantelic ◽  
Vladimir Pipic
Keyword(s):  
Light Source ◽  
Light Exposure ◽  
Light Emitting Diode ◽  
Composite Resins ◽  
Curing Time ◽  
Light Emitting ◽  
Led Light ◽  
Depth Of Cure ◽  
Dental Tissues ◽  
Hard Dental Tissues

The quality of interface between composite resin materials and hard dental tissues is highly dependent on the polymerization light source. Newly developed blue light- emitting diode units for light polymerization of dental restorative materials are the most innovative light source technology in dentistry nowadays. The aim of this work was to estimate the depth of cure of five different light-activating composite resins exposed to different irradiation times (5s, 10s, 20s and 40s) when the experimental LED light source was used. The tested materials were: Tetric Ceram (Vivadent), Point 4 (Kerr), Admira (VOCO), Filtek Z250 (3M) and Diamond Lite (DRM Lab., Inc). The depth of cure testing was determined using a penetrometer. Results after 40s curing time were as following: the deepest depth of cure was achieved after application of Filtek Z 250, Diamond Lite Point 4 and Tetric Ceram. For the restorative material Admira was found the lowest depth of cure for the light exposure of 40s. An experimental LED light source achieved a sufficient depth of cure (over 2 mm) for all tested materials after curing time of 10s. The polymerization light source spectral distribution should be considered in addition to irradiance as a depth of cure indicator.

Retinal endoilluminator toxicity of xenon and light-emitting diode (LED) light source: rabbit model

2013 ◽  
Vol 33 (3) ◽  
pp. 192-196 ◽  
Author(s):  
Bahri Aydin ◽  
Erdem Dinç ◽  
Ş. Necat Yilmaz ◽  
U. Emrah Altiparmak ◽  
Fatma Yülek ◽  
...  
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Rabbit Model ◽  
Light Emitting ◽  
Led Light

scholarly journals Design of a Secondary Freeform Lens of UV LED Mosquito-Trapping Lamp for Enhancing Trapping Efficiency

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 335 ◽  
Author(s):  
Wei-Hsiung Tseng ◽  
Diana Juan ◽  
Wei-Cheng Hsiao ◽  
Cheng-Han Chan ◽  
Hsin-Yi Ma ◽  
...  
Keyword(s):  
Light Intensity ◽  
Intensity Distribution ◽  
Light Emitting Diode ◽  
Trapping Efficiency ◽  
Axially Symmetric ◽  
Light Intensity Distribution ◽  
Light Emitting ◽  
Led Light ◽  
Uv Led ◽  
Freeform Lens

In this study, our proposed ultraviolet light-emitting diode (UV LED) mosquito-trapping lamp is designed to control diseases brought by insects such as mosquitoes. In order to enable the device to efficiently catch mosquitoes in a wider area, a secondary freeform lens (SFL) is designed for UV LED. The lens is mounted on a 3 W UV LED light bar as a mosquito-trapping lamp of the new UV LED light bar module to achieve axially symmetric light intensity distribution. The special SFL is used to enhance the trapping capabilities of the mosquito-trapping lamp. The results show that when the secondary freeform surface lens is applied to the experimental outdoor UV LED mosquito-trapping lamp, the trapping range can be expanded to 100π·m2 and the captured mosquitoes increased by about 300%.

Comparison of the effects of operating microscopes with light emitting diode and halogen light source on the eye: a rabbit study

2021 ◽  
pp. 1-7
Author(s):  
Bahri Aydın ◽  
Armagan Ozgur ◽  
Huseyin Baran Ozdemir ◽  
Pınar Uyar Gocun ◽  
Mehmet Arda Inan ◽  
...  
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Halogen Light ◽  
Halogen Light Source

scholarly journals Analysis on High-Power Seaport LED Luminaire with Uniform Light Distribution Based on Optimized Lens and Heatsink

2021 ◽  
Vol 11 (9) ◽  
pp. 4035
Author(s):  
Jinsheon Kim ◽  
Jeungmo Kang ◽  
Woojin Jang
Keyword(s):  
Light Source ◽  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Light Distribution ◽  
Light Sources ◽  
Led Light ◽  
High Power Led ◽  
Distribution Requirement ◽  
Lighting Application

In the case of light-emitting diode (LED) seaport luminaires, they should be designed in consideration of glare, average illuminance, and overall uniformity. Although it is possible to implement light distribution through auxiliary devices such as reflectors, it means increasing the weight and size of the luminaire, which reduces the feasibility. Considering the special environment of seaport luminaires, which are installed at a height of 30 m or more, it is necessary to reduce the weight of the device, facilitate replacement, and secure a light source with a long life. In this paper, an optimized lens design was investigated to provide uniform light distribution to meet the requirement in the seaport lighting application. Four types of lens were designed and fabricated to verify the uniform light distribution requirement for the seaport lighting application. Using numerical analysis, we optimized the lens that provides the required minimum overall uniformity for the seaport lighting application. A theoretical analysis for the heatsink structure and shape were conducted to reduce the heat from the high-power LED light sources up to 250 W. As a result of these analyses on the heat dissipation characteristics of the high-power LED light source used in the LED seaport luminaire, the heatsink with hexagonal-shape fins shows the best heat dissipation effect. Finally, a prototype LED seaport luminaire with an optimized lens and heat sink was fabricated and tested in a real seaport environment. The light distribution characteristics of this prototype LED seaport luminaire were compared with a commercial high-pressure sodium luminaire and metal halide luminaire.

scholarly journals Influences of Spectral Power Distribution on Circadian Energy, Visual Comfort and Work Performance

2021 ◽  
Vol 13 (9) ◽  
pp. 4852
Author(s):  
Jack Ngarambe ◽  
Inhan Kim ◽  
Geun Young Yun
Keyword(s):  
Light Source ◽  
Power Distribution ◽  
Work Performance ◽  
Spectral Power ◽  
Light Emitting Diode ◽  
Essential Element ◽  
Visual Comfort ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Spectral Power Distribution

Spectral power distribution (SPD) is an essential element that has considerable implications on circadian energy and the perception of lit environments. The present study assessed the potential influences of SPD on energy consumption (i.e., considering circadian energy), visual comfort, work performance and mood. Two lighting conditions based on light-emitting diode (LED) and organic light-emitting diode (OLED) were used as proxies for SPDs of different spectral content: dominant peak wavelength of 455 nm (LED) and 618 nm (OLED). Using measured photometric values, the circadian light (CL), melatonin suppression (MS), and circadian efficacy (CE) of the two lighting sources were estimated via a circadian-phototransduction model and compared. Additionally, twenty-six participants were asked to evaluate the said lit environments subjectively in terms of visual comfort and self-reported work performance. Regarding circadian lighting and the associated energy implications, the LED light source induced higher biological actions with relatively less energy than the OLED light source. For visual comfort, OLED lighting-based conditions were preferred to LED lighting-based conditions, while the opposite was true when considering work performance and mood. The current study adds to the on-going debate regarding human-centric lighting, particularly considering the role of SPD in energy-efficient and circadian lighting practices.

scholarly journals Optimal Color Lighting for Scanning Images of Flat Panel Display using Simplex Search

2018 ◽  
Vol 4 (11) ◽  
pp. 133
Author(s):  
HyungTae Kim ◽  
EungJoo Ha ◽  
KyungChan Jin ◽  
ByungWook Kim
Keyword(s):  
Image Quality ◽  
Light Source ◽  
Light Emitting Diode ◽  
Optical Filters ◽  
Flat Panel Display ◽  
Flat Panel ◽  
Light Emitting ◽  
Simplex Search ◽  
Inspection Systems ◽  
Color Control

A system for inspecting flat panel displays (FPDs) acquires scanning images using multiline charge-coupled device (CCD) cameras and industrial machine vision. Optical filters are currently installed in front of these inspection systems to obtain high-quality images. However, the combination of optical filters required is determined manually and by using empirical methods; this is referred to as passive color control. In this study, active color control is proposed for inspecting FPDs. This inspection scheme requires the scanning of images, which is achieved using a mixed color light source and a mixing algorithm. The light source utilizes high-power light emitting diodes (LEDs) of multiple colors and a communication port to dim their level. Mixed light illuminates an active-matrix organic light-emitting diode (AMOLED) panel after passing through a beam expander and after being shaped into a line beam. The image quality is then evaluated using the Tenenbaum gradient after intensity calibration of the scanning images. The dimming levels are determined using the simplex search method which maximizes the image quality. The color of the light was varied after every scan of an AMOLED panel, and the variation was iterated until the image quality approached a local maximization. The number of scans performed was less than 225, while the number of dimming level combinations was 20484. The proposed method can reduce manual tasks in setting-up inspection machines, and hence is useful for the inspection machines in FPD processes.

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