Investigation of Temperature Regime and Luminous Flux of Light-Emitting Element of Light Emitting Diode Lamp (original) (raw)

Study of Temperature Effect on Luminous Flux of High Power Chip on Board Light Emitting Diode

Communications in Physics, 2014

High power chip-on-board light emitting diode (HPCOBLED) is a promising solid state light technology for a variety of lighting applications. In this paper, we study temperature effect on luminous flux of HPCOBLED using VMI-PR-001 system of Vietnam Metrology Institute. The results show that when the case temperature (T c) increases, luminous flux decreases. In particular, when HPCOBLED is of high power, the decrease of luminous flux is larger. An explanation for this result is consumed power on the LED. We proposed HPCOBLED model modified from Hodapp's model using temperature gradient between p-n junction of device and heat radiator for description of the temperature effect on luminous flux of HPCOBLED. The calculation results for the modified HPCOBLED model match with those experimental values measured by the luminous flux measurement system (VMI-PR-001, Vietnam).

Thermal analysis of LED spot lighting device operating in external natural or forced heat convection

Microelectronics Reliability, 2013

A high brightness LED spot lighting device has been under examination. The device has one multichip LED module which nominal electric power is 15 W. A 3D simulation model has been created and simulated with Comsol Multiphysics software. The temperatures of the LED chip junction, the LED module and the heatsink and have been simulated using a finite-element-method (FEM) software. Simulations have been validated with measurements. Main heat flow paths and the associated thermal resistances in a stationary condition have been resolved. Simulations have been made for the case of external natural and forced external heat convection. Time dependent simulations resolved the time constants of the lamp. The time constants were calculated also by using the thermal resistances and heat capacities of the lamp. Use of thermal grease between the LED module and the heatsink reduces chip temperature. This has also been simulated. Photometric characteristics of the light device, especially luminous flux versus input electrical power and lamp temperature, have been measured. One LED spot light device with a defected LED module was found in photometric measurements and IR-imaging.

LED lamp - design and thermal management investigations

2012 35th International Spring Seminar on Electronics Technology, 2012

The aims of this work are connected with development of new method of LEDs' mounting onto the heat sink in lighting equipment. The technique involves usage of copper pins instead of standard MCPCBs. LEDs are soldered on copper pins. Mounting of LEDs demands boring holes in the heat sink and fixing copper pins into the holes by thermal conductive epoxy resin only. LED lamp is made using new technology and LEDs' thermal performance investigations are made at various ambient conditions (air temperatures from 20ºC to 45ºC) and different current values through LEDsup to 600 mA. Temperature regimes of operation of power LEDs soldered on MCPCBs and on copper pins (and mounted on heat sink) are experimentally tested and compared. Experimental results show that utilization of copper pins underneath LED thermal pads ensures good dissipation of heat, good manufacturability, enables varied designs of light equipment and is cost effective.

Design Methodology for Light-Emitting Diode Systems by Considering an Electrothermal Model

IEEE Transactions on Electron Devices, 2000

The knowledge about thermal, electrical, and photometrical characteristics of Light-Emitting Diodes (LEDs) is essential to achieve a good performance to the lighting system. This paper presents a methodology for designing LED systems. The main purpose is to provide an optimal operating point, considering the electrothermal design to achieve the maximum luminous flux for a given LED system. Based on two design routines, the proposed methodology brings the possibility to consider driver output current, heatsink size, and LED junction temperature in the system design. A mathematical analysis taking into account an LED electrothermal model is presented. Computational fluid dynamics simulation employing finite element method and experimental results validate the proposed methodology.

Influence of temperature in the performance of the LED lamp

Revista Brasileira de Aplicações de Vácuo, 2020

In this work, we analyze the temperature of the LED lamp of white emission with 9 W with or without the influence of the cooling process using a fan. The investigation was carried out by seven different methods: (1) Analysis of temperature close to LEDs inside the bulb (diffuser); (2) Analysis of temperature on LEDs without bulb; (3) Analysis of temperature on LEDs without bulb with cooling using a fan; (4) Analysis of temperature on LEDs board out of body lamp without bulb; (5) Analysis of temperature on LEDs board out of body lamp without bulb with cooling using a fan. This last analysis 5 exhibited better results, decreasing the significant temperature on the LED surface from ≈130ºC (found in analysis 2) to ≈45ºC. Due to good results exhibited in analysis 5, it was used in the illuminance measurements of the LED lamp without cooling in the analysis 6, and with a fan as analysis 7. Both results compared showed that using a fan had a great influence, and difference on the illuminance values by elapsed time from ≈47,000 lux without a fan (analysis 6) to ≈55,300 lux with fan (analysis 7), and also the use of a fan exhibited the lowest time of stabilization in 1 minute only.

Thermal Simulation and Analysis of the Single LED Module

JST: Smart Systems and Devices, 2021

Light Emitting Diodes (LED) shows an important role in replacing traditional lamps due to their longevity, high efficiency, and environment-friendly operation. However, a large portion of the electricity applied on LED converts to heat, raising up the p-n junction working temperature, and lowering the output-light quality and the LED lifetime as well. Therefore, thermal management for LED is one of the key issues in LEDs lighting application. In order to investigate the impact of each component of the LED module on the junction temperature of the LED, we have performed thermal simulations of a typical single LED module by using the finite element method. Effects of thermal conductivity and thickness of each module’s components on junction temperature were analyzed systematically. The results provided a detailed understanding of thermal behavior of a single LED module and established a crucial insight into thermal management design for high-power white LED lamp. Thermal-interface-mat...

Investigation of the LEDs heat sinks

IOSR Journal of Mechanical and Civil Engineering, 2016

Junction temperature is an important parameter in thermal management of LEDs (Light emitting diodes) system. The junction temperature of three different types of LED is calculated numerically. Three dimension numerical simulation using ANSYS-Icepak 15 software package is presented for all cases. Appropriate heat sink is designed for each type of LED and investigates the effect of the fins height on the junction temperature. The increasing in electrical current utilized to driving the LEDs has concentrate high notice on the thermal management in the evolution of LED system. A felicitous design should have minimum thermal resistance between the heat sink base and the junction that depends on conduction heat transfer. The results showed the increase in a heat sink height 10% dissipate more heat transfer from the LEDs system at approximately 15%.

Heat dissipation of high-power light emitting diode chip on board by a novel flat plate heat pipe

Applied Thermal Engineering, 2017

A new flat plate heat pipe (FPHP) which has many parallel-arranged micro-fins casted on the condensation surface was designed and fabricated. An experimental system for studying the thermal performance of this FPHP when applied for cooling high-power LED (light emitting diode) COBs (chip on board) was also set up. From experiments, the new FPHP is found to be more effective for heat dissipation of high-power LED COBs than the traditional FPHP. The thermal resistance of the new FPHP is 10-15% lowered and the temperature uniformity at the condensation surface of FPHP is approximately at the same level in comparison with the traditional FPHP. Numerical simulation with respect to LED COB cooling by the new FPHP was performed additionally. The obtained simulation results accord well with the experimental results, inter-proving the reliability of the obtained results and further corroborating the effectiveness of the new FPHP as applied for heat dissipation of high-power LED COBs.

Design and Thermal Analysis of High Power LED Light

2021

In the development of lighting technologies, light emitting diode (LED) technology plays an important role due to its high efficiency. LED lightening is the future of indoor and outdoor illumination solutions that all around of the world there is a widespread transition to save energy and have better quality illumination via LED-based solutions. On other hand, cooling of high power LED is crucial factor to utilize LED in high performance. In addition, finned heat sink could not be efficient based on the its geometry and usage areas due to the powder, the rain and the muds effects. In this study, an un-finned heat sink LED armature consisting of aluminum sheet metal was designed using a computer-aided-design (CAD) program. Furthermore, manufacturing of the heat sinks from sheet metal plates with bending machines enables to increase variety of LED armatures cheaply according to design requirements. Then, the thermal analysis of the system was conducted for the case of natural heat con...

Thermal Design of LED by DOE

Electrical and Electronics Engineering: An International Journal, 2015

The article analyses the influence of the design parameters of the structure of the heat sink with round pins on the junction temperature of the LED system. The study uses design of experiment (DOE) and thermal simulations to determine the factors that have the greatest impact to improve the cooling capacity and finding the optimal heat sink design. The results of thermal design and simulation of the LED system have been validated experimentally using a thermocouple and they show that the error between the experimentally measured and simulated temperature value of optimized heat sink structure is below 6%.