Performance Analysis of Various Types of High Power Light Emitting Diodes

2018 ◽  
pp. 91-98 ◽  
Author(s):  
Kamalika Ghosh ◽  
Debashis Raul
Keyword(s):  
High Power ◽  
Light Emitting Diode ◽  
Life Time ◽  
Effect Of Temperature ◽  
Light Sources ◽  
Test Results ◽  
Light Emitting ◽  
Tropical Countries ◽  
Cause Of Failure ◽  
Very High

Solid state, energy efficient light emitting diode (LED) technology is coming up to replace the conventional gas discharge, etc. light sources. Although declared life of LED is very high but in tropical countries their life time appears very short. This phenomenon is becoming the most drawbacks for usage of LED. To search out the reason for the failure lead to undertake thorough study on the performance of LED specifically on the various environmental conditions. Experimentation was carried out with various types of commercially available high power LED. Failure in tropical countries may be due to effect of temperature. Test results have been noted at various major parts of LEDs, e.g. die, and sink area. Detail analysis of test results at various parts of LEDs in different conditions tends to have some idea about the cause of failure of the LEDs in tropical countries with high ambient temperature and less scope of heat generation by the light source.

Reliability of High-Power Light Emitting Diode Attached With Different Thermal Interface Materials

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Xin Li ◽  
Xu Chen ◽  
Guo-Quan Lu
Keyword(s):  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Temperature Cycling ◽  
Fluorescent Light ◽  
Light Sources ◽  
Light Emitting ◽  
Die Attach ◽  
Nanosilver Paste ◽  
Interconnection Material

As a solid electroluminescent source, white light emitting diode (LED) has entered a practical stage and become an alternative to replace incandescent and fluorescent light sources. However, due to the increasing integration and miniaturization of LED chips, heat flux inside the chip is also increasing, which puts the packaging into the position to meet higher requirements of heat dissipation. In this study, a new interconnection material—nanosilver paste is used for the LED chip packaging to pursue a better optical performance, since high thermal conductivity of this material can help improve the efficiency of heat dissipation for the LED chip. The bonding ability of this new die-attach material is evaluated by their bonding strength. Moreover, high-power LED modules connected with nanosilver paste, Sn3Ag0.5Cu solder, and silver epoxy are aged under hygrothermal aging and temperature cycling tests. The performances of these LED modules are tested at different aging time. The results show that LED modules sintered with nanosilver paste have the best performance and stability.

Light-emitting diodes as light sources for spectroscopy: Sensitivity to temperature

2017 ◽  
Vol 25 (6) ◽  
pp. 416-422 ◽  
Author(s):  
Clinton J Hayes ◽  
Kerry B Walsh ◽  
Colin V Greensill
Keyword(s):  
Ambient Temperature ◽  
Near Infrared ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Junction Temperature ◽  
Effect Of Temperature ◽  
Light Sources ◽  
Spectral Variation ◽  
Light Emitting ◽  
Full Intensity

Understanding of light-emitting diode lamp behaviour is essential to support the use of these devices as illumination sources in near infrared spectroscopy. Spectral variation in light-emitting diode peak output (680, 700, 720, 735, 760, 780, 850, 880 and 940 nm) was assessed over time from power up and with variation in environmental temperature. Initial light-emitting diode power up to full intensity occurred within a measurement cycle (12 ms), then intensity decreased exponentially over approximately 6 min, a result ascribed to an increase in junction temperature as current is passed through the light-emitting diode. Some light-emitting diodes displayed start-up output characteristics on their first use, indicating the need for a short light-emitting diode ‘burn in’ period, which was less than 24 h in all cases. Increasing the ambient temperature produced a logarithmic decrease in overall intensity of the light-emitting diodes and a linear shift to longer wavelength of the peak emission. This behaviour is consistent with the observed decrease in the IAD Index (absorbance difference between 670 nm and 720 nm, A670–A720) with increased ambient temperature, as measured by an instrument utilising light-emitting diode illumination (DA Meter). Instruments using light-emitting diodes should be designed to avoid or accommodate the effect of temperature. If accommodating temperature, as light-emitting diode manufacturer specifications are broad, characterisation is recommended.

scholarly journals IN VITRO DEVELOPMENT OF YELLOW LAPACHO (BIGNONIACEAE) USING HIGH-POWER LIGHT EMITTING DIODE

2018 ◽  
Vol 42 (5) ◽  
Author(s):  
Ezequiel Enrique Larraburu ◽  
Gonzalo Sanchez Correa ◽  
Berta Elizabet Llorente
Keyword(s):  
In Vitro Culture ◽  
High Power ◽  
Stomatal Density ◽  
Light Emitting Diode ◽  
Dry Weight ◽  
Light Sources ◽  
Multiplication Rate ◽  
Light Emitting ◽  
Shoot Dry Weight

ABSTRACT Handroanthus ochraceus (yellow lapacho) is a medicinal, ornamental and timber tree which can be propagated by in vitro culture. Conventional methods use fluorescent lighting (FL), whereas light emitting diode (LED) has been used for this purpose only recently. The aim of this work was to evaluate the effects of FL and high-power LED (HP-LED) on the in vitro multiplication and rooting of yellow lapacho at different irradiances (15 to 60 µmol m-2s-1). Epicotyls obtained from half-siblings was multiplicated in WPM (Woody Plant Medium) supplemented with 20 µM benzilaminopurine and 1 mM IBA (indolebutiric acid). For rooting, shoots were cultured for 3 days in ½WPM supplemented with 50 µM IBA and for 42 days in auxin-free ½WPM under HP-LED or FL lighting. Under HP-LED, the multiplication rate of shoots increased significantly (61%) from 20 to 40 µmol m-2s-1 respect to FL. Differences in abaxial stomatal density and size were observed between light sources at 20 µmol m-2s-1. High HP-LED irradiance produced the highest rooting percentage. In the rooting stage, the marginal means of treatments without factors interaction showed that HP-LED irradiances significantly increased shoot length by 20%, shoot fresh weight by 77% and shoot dry weight by 30% in comparison to the values under FL. The maximum values calculated from the regression curves were around 50 µmol m-2 s-1 for HP-LED for all parameters except root lenght whereas were around 20 µmol m-2 s-1 for FL for all parameters except fresh and dry weigth of shoot. Here we show that HP-LED lighting improve in vitro culture of H. ochraceus, reduced 81% energy consumption respect to FL and uses only a multispectral LED instead of different single color LEDs. Therefore, HP-LED could be useful for the micropropagation of tree species contributing to sustainable agriculture and ecological restoration of degraded areas.

Heat Transfer Enhancement of the Liquid-Cooled LED Illumination Module

2013 ◽  
Vol 284-287 ◽  
pp. 768-772 ◽  
Author(s):  
Rong Yuan Jou
Keyword(s):  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Light Sources ◽  
The Finite Element Method ◽  
Liquid Cooling ◽  
Light Emitting ◽  
A Tec ◽  
Heat Sink Design ◽  
Temperature And Flow Fields

High-power light emitting diode (LED) modules offer several advantages over conventional light sources, but require effective thermal management for optimal performance, such as liquid cooling or thermoelectric cooling (TEC). This study compared the thermal performance of high-power LEDs with liquid cooling and TEC using both the finite element method and experiments. We considered a mutichip module in which the LEDs are immersed in one of three different cooling fluids in a metal enclosure with passive cooling or a TEC module. In the experiments, temperatures were measured by thermocouples. The temperature and flow fields of the liquid-cooled package inside the enclosure were analyzed in detail using a numerical model, and the results were validated against the experimental measurements. In this paper, we discuss the major design considerations when using liquid cooling and TEC. Our results show that for the illumination module considered in this study, appropriate heat sink design is crucial to optimizing performance with TEC, which can enhance the heat dissipation for small and compact LED modules.

Wafer-Level Light Emitting Diode (WL-LED) Chip Simplified Package for Very-High Power Solid-State Lighting (SSL) Source

2016 ◽  
Vol 37 (2) ◽  
pp. 197-200 ◽  
Author(s):  
Yibin Zhang ◽  
Jianwei Xu ◽  
Mingdi Ding ◽  
Desheng Zhao ◽  
Hongjuan Huang ◽  
...  
Keyword(s):  
Solid State ◽  
High Power ◽  
Light Emitting Diode ◽  
Solid State Lighting ◽  
Wafer Level ◽  
Light Emitting ◽  
Very High

Life-time estimation of high-power blue light-emitting diode chips

2009 ◽  
Vol 49 (9-11) ◽  
pp. 1231-1235 ◽  
Author(s):  
Jeung-Mo Kang ◽  
Jae-Wook Kim ◽  
Jeong-Hyeon Choi ◽  
Du-Hyun Kim ◽  
Ho-Ki Kwon
Keyword(s):  
Blue Light ◽  
High Power ◽  
Light Emitting Diode ◽  
Time Estimation ◽  
Life Time ◽  
Light Emitting

Effect of Temperature and Current on Luminous Efficiency of High Power LED

2011 ◽  
Vol 347-353 ◽  
pp. 310-313 ◽  
Author(s):  
Feng Rao ◽  
Zhi Chen Ge ◽  
Jin Lian Zhu
Keyword(s):  
Energy Saving ◽  
White Light ◽  
High Power ◽  
Light Emitting Diode ◽  
Luminous Efficiency ◽  
Effect Of Temperature ◽  
Light Emitting ◽  
Led Light ◽  
High Power Led ◽  
Changing Rate

Luminous efficiency of high power white light LED (light emitting diode) at different temperature and driver current is measured with the photometric, chromatic and electric characteristics analyzer. It is shown that the luminous efficiency decreases as the temperature and (or) the driver current increases. The highter the driver current is, the more strongly temperature worsens the efficiency. However, the changing rate of efficiency with current is similar at different temperature. At last, a luminous efficiency model with temperature and current is constructed. This research is very important for the design of energy-saving LED lamps.

scholarly journals The Development of LED-Based Dental Light Using a Multiplanar Reflector Design

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Chi-Chang Hsieh ◽  
Yan-Huei Li
Keyword(s):  
Energy Consumption ◽  
Energy Saving ◽  
High Power ◽  
Light Emitting Diode ◽  
Luminous Flux ◽  
International Standards ◽  
Light Sources ◽  
Light Emitting ◽  
Standards And Regulations ◽  
Reduce Energy Consumption

A multiplanar reflector was designed to enhance the application efficiency of light-emitting diode (LED) light sources that can be employed as LED-based dental lights. This study used a high-power LED developed by Nichia, that is, a single LED capable of providing a total luminous flux of 120 lm, as the primarily light source to design and develop an LED-based dental light. This LED complies with the international standards and regulations stipulated in ISO 9680:2007. The light spots produced by the prototype were rectangular, with a length of 200 mm and a width of 100 mm. These light spots achieved maximum illumination of 12,000 lux. The use of LEDs can reduce energy consumption from 50 W to 3 W, providing an energy saving of more than 90%.

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