scholarly journals Comparison of Current–Voltage Response to Diagnostic X-rays of Five Light-Emitting Diode Strips

2019 ◽  
Vol 10 (1) ◽  
pp. 200 ◽  
Author(s):  
Edrine Damulira ◽  
Muhammad Yusoff ◽  
Suharti Sulaiman ◽  
Nur Zulkafli ◽  
Nur Zulkifli ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Low Cost ◽  
Voltage Response ◽  
White Led ◽  
X Rays ◽  
Light Emitters ◽  
Light Emitting ◽  
X Ray ◽  
Reproducibility Study ◽  
Current Voltage

Light-emitting diodes (LEDs) have miscellaneous applications owing to their low cost, small size, flexibility, and commercial availability. Furthermore, LEDs have dual applicability as light emitters and detectors. This study explores the current–voltage (C–V) response of LED strips exposed to diagnostic x-rays. Cold white, warm white, red, green, and blue LED strip colors were tested. Each strip consisted of 12 LED chips and was connected to a multimeter. The variable diagnostic x-ray parameters evaluated were kilovoltage peak (kVp), milliampere-seconds (mAs), and source-to-image distance (SID). The radiation dose was also measured using a dosimeter simultaneously exposed to x-rays perpendicularly incident on the strips. Lastly, the consistency of C–V responses, and any possible degradation after 1–2 months was also analyzed. Each LED strip color was ranked according to its C–V response in each of the investigated parameters. The LED strip color with the best cumulative rank across all the tested parameters was then examined for reproducibility. Our findings revealed that the C–V responses of LED strips are (a) generally low but measurable, (b) inconsistent and fluctuating as a consequence of kVp variations, (c) positively correlated to mAs, (d) negatively correlated to SID, and (e) positively correlated to dose. Overall results suggested cold white LED strip as most feasible for x-ray detection—in comparison to examined colors. Additionally, the reproducibility study using the cold white LED strip found a similar trend of C–V response to all variables except kVp. Outcomes indicate that LED strips have the potential to be exploited for detecting low dose (~0–100 mGy) diagnostic x-rays. However, future studies should be carried out to increase the low C–V signal.

scholarly journals Design and Analyze the Effect of InGaN Nano-Material in Light Emitting Diode towards Improving the Performance of Quantum Efficiency

2019 ◽  
Vol 8 (2) ◽  
pp. 6321-6325
Keyword(s):  
Active Region ◽  
Electric Field ◽  
Epitaxial Growth ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Ex Situ ◽  
Internal Electric Field ◽  
Light Emitters ◽  
Light Emitting ◽  
Nano Material

The efficiency of an InGaN light-emitting diode (LED) is critically dependent on internal electric field (IEF) exhibiting in its active region. In the present work we examined the properties of the NSSP light emitters. Also we developed a novel InGaN LED structure based on a Nano-structured semi-polar (NSSP) GaN template. This new structure can be fabricated on a mature c-plane substrate including low cost sapphire without any ex situ patterning. From this approach we got results in which we can see that with the help of RT PL, 30% enhancement in IQE will be observed in NSSP MQWs as compared to c-plane planar MQWs with the help of SEM and TEM imaging tools. We have successfully ramped up an MOCVD tool for the epitaxial growth of GaN LEDs for this study.

Porphyrin doping of dichloride-bis(5,7-dichloroquinolin-8-olato)tin(IV) complex for electroluminescence

2013 ◽  
Vol 17 (05) ◽  
pp. 351-358 ◽  
Author(s):  
Mohammad Janghouri ◽  
Ezeddin Mohajerani ◽  
Mostafa M. Amini ◽  
Naser Safari
Keyword(s):  
Molecular Orbital ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Energy Levels ◽  
Orbital Energy ◽  
Homogeneous Layer ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Fundamental Structure ◽  
Organic Light

A method for obtaining red emission from an organic-light emitting diode has been developed by dissolving red and yellow dyes in a common solvent and thermally evaporating the mixture in a single furnace. Dichlorido-bis(5,7-dichloroquinolin-8-olato)tin(IV) complex ( Q2SnCl2 , Q = 5,7-dichloro-8-hydroxyquinoline) has been synthesized for using as a fluorescent material in organic light-emitting diodes (OLEDs). The electronic states HOMO (Highest Occupied Molecular Orbital)/LUMO (Lowest Occupied Molecular Orbital) energy levels explored by means of cyclic voltammetry measurements. A device with fundamental structure of ITO/PEDOT:PSS (55nm)/PVK (90nm)/ Q2SnCl2/Al (180nm) was fabricated and its electroluminescence performance at various thicknesses of light emitting layer (LEL) of Q2SnCl2 is reported. By following this step, an optimal thickness for the doping effect was also identified and explained. Finally a device with fundamental structure of ITO/PEDOT:PSS (55nm)/PVK (90nm)/meso-tetraphenylporphyrin (TPP): Q2SnCl2 (75nm)/ Al (180nm) was fabricated and its electroluminescence performance at various concentrations of dye has been investigated. It is shown that this new method is promising candidate for fabrication of low cost OLEDs at more homogeneous layer.

Evaluation of Static Performance of Optoelectronic Semiconductor Devices under X-Rays Irradiation

2010 ◽  
Vol 173 ◽  
pp. 1-6 ◽  
Author(s):  
Haider F. Abdul Amir ◽  
Fuei Pien Chee
Keyword(s):  
Ionizing Radiation ◽  
Light Emitting Diode ◽  
Optoelectronic Devices ◽  
Third Party ◽  
Infrared Light ◽  
X Rays ◽  
Total Ionizing Dose ◽  
Light Emitting ◽  
Static Performance ◽  
Current Drives

In this research, optoelectronic devices consisted of an infrared light emitting diode and a phototransistor with no special handling or third party-packaging were irradiated to ionizing radiation utilizing x-rays. It was found that the devices under test (DUTs) undergo performance degradation in their functional parameters during exposure to x-rays. These damaging effects are depending on their current drives and also the Total Ionizing Dose (TID) absorbed. The TID effects by x-rays are cumulative and gradually take place throughout the lifecycle of the devices exposed to radiation.

Low Cost Cooling Device for High Power LED Lamps

2020 ◽  
Author(s):  
Pamela Martinez-Vega ◽  
Araceli Lopez-Badillo ◽  
J. Luis Luviano-Ortiz ◽  
Abel Hernandez-Guerrero ◽  
Jaime G. Cervantes
Keyword(s):  
Reference Model ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Cost Effective ◽  
Heat Sinks ◽  
Modern World ◽  
Type Model ◽  
Light Emitting

Abstract The modern world progressively demands more energy; according to forecasts energy consumption will grow at an average annual rate of 3 percent. Therefore, it is necessary to purchase products or devices that are efficient and environmentally friendly. Technology in LED (Light Emitting Diode) lighting is presented as an alternative to energy saving, since LEDs have proven to be extremely efficient, have a long service life and their cost-effective ratio is very good. However, the heat emitted by the LED chip must be dissipated effectively, since the overheating of the chip reduces the efficiency and lifetime of the lamp. Therefore, heat sinks that are reliable, efficient and inexpensive should be designed and built. The present work proposes new designs for heat sinks in LED lamps, some of the models in the design of the fins refer to the Fibonacci series. The models proposed in the present work that have a significant advantage are the Type 1E Model (5.2% mass savings and better thermal efficiency of 8.33%), GR Type 1 Model (3.12% lighter and 3.33% more efficient) and the GRL Type Model (4. 51% mass savings and 5.55% thermally more efficient) compared to the Type 2 Reference Model proposed by Jang et al. [12].

scholarly journals Preparation of Organic Light-Emitting Diode Using Coal Tar Pitch, a Low-Cost Material, for Printable Devices

PLoS ONE ◽  
2013 ◽  
Vol 8 (5) ◽  
pp. e62903 ◽  
Author(s):  
Miki Yamaoka ◽  
Shun-suke Asami ◽  
Nayuta Funaki ◽  
Sho Kimura ◽  
Liao Yingjie ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Low Cost ◽  
Coal Tar ◽  
Coal Tar Pitch ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light

Electrostatic Discharge Characteristics of InGaN/GaN Light-Emitting Diodes with Si-Doped Graded Superlattice

2015 ◽  
Vol 15 (10) ◽  
pp. 7733-7737 ◽  
Author(s):  
Kwanjae Lee ◽  
Cheul-Ro Lee ◽  
Jin Soo Kim ◽  
Jin Hong Lee ◽  
Kee Young Lim ◽  
...  
Keyword(s):  
Light Emission ◽  
Electrostatic Discharge ◽  
Light Emitting Diode ◽  
Emission Spectra ◽  
Small Variation ◽  
Injection Current ◽  
Light Emitting ◽  
Current Voltage ◽  
Gan Led ◽  
Si Doped

We report the influences of a Si-doped graded superlattice (SiGSL) on the electrostatic discharge (ESD) characteristics of an InGaN/GaN light-emitting diode (LED). For comparison, a conventional InGaN/GaN LED (C-LED) was also investigated. The luminous efficacy for the SiGSL-LED was 2.68 times stronger than that for the C-LED at the injection current of 20 mA. The resistances estimated from current–voltage (I–V) characteristic curves were 16.5 and 8.8 Ω for the C-LED and SiGSL-LED, respectively. After the ESD treatment at the voltages of 4000 and 6000 V, there was no significant change in the I–V curves for the SiGSL-LED. Also, there was small variation in the I–V characteristics for the SiGSL-LED at the ESD voltage of 8000 V. However, the I–V curves for the C-LED were drastically degraded with increasing ESD voltage. While the light emission was not observed at the injection current of 20 mA from the C-LED sample after the ESD treatment, the emission spectra for the SiGSL-LED sample were clearly measured with the output powers of 10.47, 9.66, and 7.27 mW for the ESD voltages of 4000, 6000, and 8000 V respectively.

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.

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