scholarly journals Compact Measurement of the Optical Power in High-Power LED Using a Light-Absorbent Thermal Sensor

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4690
Author(s):  
You-Young Kim ◽  
Jae-Young Joo ◽  
Jong-Min Kim ◽  
Sun-Kyu Lee
Keyword(s):  
High Power ◽  
Light Emitting Diode ◽  
Hot Spot ◽  
Thermal Power ◽  
Temperature Response ◽  
Reference Value ◽  
Optical Power ◽  
Junction Temperature ◽  
Integrating Sphere ◽  
Thermal Sensor

LED (Light-Emitting Diode) presents advantages such as luminescence, reliability, durability compared with conventional lighting. It has been widely applied for life, healthcare, smart farm, industry, and lighting from indoor to the automotive headlamp. However, the LED is vulnerable to thermal damage originated from the high junction temperature, especially in high power applications. Hence, it requires precise qualification on the optical power and the junction temperature from the pilot line to secure reliability. In this study, the photo-thermal sensor is proposed by employing a sheet-type thermocouple composed of photo-absorbent metal film and thermocouple. This sensor aims low-cost qualification in pilot line for high-power luminous devices and optical monitoring of costly luminaire such as automobile LED headlamp. The sensor is designed to detect the increased temperature response of LED hot spots from the transferred thermal power and absorbed optical power. The temperature response of each sheet-type thermocouple is utilized as a signal output of the absorbed optical power and hot spot temperature based on the introduced sensor equation. The proposed thermal sensor is evaluated by comparing the experiment with the measured reference value from the integrating sphere and the attached thermocouple at a junction. The experiment result reveals 3% of the maximum error for the optical power of 645 mW.

High Power LED Integrated With Silicon-Based Thermoelectric Cooler Package

2007 ◽  
Author(s):  
Ming-Ji Dai ◽  
Chih-Kuang Yu ◽  
Chun Kai Liu ◽  
Sheng-Liang Kuo
Keyword(s):  
High Power ◽  
Flip Chip ◽  
Light Emitting Diode ◽  
Infrared Camera ◽  
Junction Temperature ◽  
Integrating Sphere ◽  
Thermoelectric Cooler ◽  
High Power Led ◽  
Silicon Based ◽  
Light Efficiency

A new thermal management application of silicon-based thermoelectric (TE) cooler integrated with high power light emitting diode (LED) is investigated in present study. The silicon-based TE cooler herein is fabricated by MEMS fabrication technology and flip-chip assembly process that is used for high power LED cooling. An electrical-thermal conversion method is used to estimate the junction temperature of LED. Moreover, the Integrating Sphere is also used to measure the light efficiency of LED. The thermal images photographed by infrared camera demonstrated the cooling function of the silicon-based TE devices. The results also show that high power LED integrated with silicon-based thermoelectric cooler package can effectively reduce the thermal resistance to zero. In addition, the light efficiency of the LED (1W) will increase under low TE cooler input power (0.55W), which is about 1.3 times of that without TE cooler packaging.

Thermal Analysis of High Power Light Emitting Diodes Package

2011 ◽  
Vol 687 ◽  
pp. 215-221
Author(s):  
Yuan Yuan Han ◽  
Hong Guo ◽  
Xi Min Zhang ◽  
Fa Zhang Yin ◽  
Ke Chu ◽  
...  
Keyword(s):  
Finite Element Method ◽  
High Power ◽  
Thermal Field ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Convective Heat Exchange ◽  
Input Power ◽  
Junction Temperature ◽  
Original Structure ◽  
Light Emitting

With increasing of the input power of the chips in light emitting diode (LED)， the thermal accumulation of LEDs package increases. Therefore solving the heat issue has become a precondition of high power LED application. In this paper, finite element method was used to analyze the thermal field of high power LEDs. The effect of the heatsink structure on the junction temperature was also investigated. The results show that the temperature of the chip is 95.8°C which is the highest, and it meets the requirement. The conductivity of each component affects the thermal resistance. Convective heat exchange is connected with the heat dissipation area. In the original structure of LEDs package the heat convected through the substrate is the highest, accounting for 92.58%. Three heatsinks with fin structure are designed to decrease the junction temperature of the LEDs package.

5mm × 5mm Sized Slug on High Power LED Stress and Junction Temperature Analysis

2013 ◽  
Vol 404 ◽  
pp. 460-464
Author(s):  
Zaliman Sauli ◽  
Vithyacharan Retnasamy ◽  
Fairul Afzal Ahmad Fuad ◽  
Phaklen Ehkan ◽  
Rajendaran Vairavan ◽  
...  
Keyword(s):  
High Power ◽  
Light Emitting Diode ◽  
Input Power ◽  
Junction Temperature ◽  
Temperature Analysis ◽  
Single Chip ◽  
Physical Size ◽  
Light Emitting ◽  
Simulation Results ◽  
Incandescent Lamps

Conventional incandescent lamps are being replaced by high power light emitting diode as a lighting source due to it ascendancy in terms of physical size, performance, output and lifetime. Nevertheless, the reliability and efficiency of the LED is dependent on the junction temperature. This study presents the thermal simulation of single chip LED package with 5mm x5mmx 1mm aluminum heat slug. The junction temperature and stress of LED chip were evaluated using Ansys version 11. Input power of 0.1 W and 1 W were applied to the LED. The simulation results showed that at input power of 1W, the maximum junction temperature and stress of the LED chip is 112.91°C and 263.82Mpa respectively.

Thermal Characteristics of High-Power LED Packages with Dissipation Film

2013 ◽  
Vol 397-400 ◽  
pp. 1767-1771
Author(s):  
Cheng Yi Hsu ◽  
Yu Li Lin
Keyword(s):  
High Power ◽  
Diamond Film ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Thermal Characteristics ◽  
Large Change ◽  
Junction Temperature ◽  
Conduction Model ◽  
Element Analysis ◽  
Light Emitting

A simple, fast, and reliable characterization method for measuring junction temperature (Tj) on high power GaN-based light emitting diodes (LED) was presented in this study. Thermal characteristics of high power Light-emitting-diode have been analyzed by using a three-dimensional thermal conduction model. Maximum operation temperature has also been calculated. The induced thermal behaviors of the best package processes for LED device with diamond film were investigated by finite element analysis (FEA) and by experimental measurement. The large change of forward operation voltage with temperature in light emitting diodes is advantageously used to measure junction temperature. Using this method, junction temperature (Tj) of LED under various structures and chip mounting methods was measured. It was found that the junction temperature can be reduced considerably by using diamond film substrates to replace sapphire substrate. In this study, the junction temperature can be decreased by about 14.3% under 1.5W power and decreased by about 15.9% under 1W power for 1mm square die. The thermal resistance (RT) can be measured to be 14.8°C/W under 1.5W power and 16.6°C/W under 1.W power.

The Color Mixing White-Light LEDs

2013 ◽  
Vol 378 ◽  
pp. 440-443
Author(s):  
Chiu Jung Yang ◽  
Chien Sheng Huang ◽  
Chih Wei Chen ◽  
Po Wen Chen
Keyword(s):  
White Light ◽  
Light Emitting Diode ◽  
Optical Power ◽  
Integrating Sphere ◽  
Light Spectrum ◽  
Light Emitting ◽  
Driver Circuit ◽  
Color Mixing ◽  
Color Rendering

Thepaperis discussedin coloruniformity study.The experiment divided into two steps in this study,first is modules design and simulation. Second is fabrication and measurement.After measure the LEDs property, calculating the ratio of each colored LEDs by using Grassmanns Law,modeling by Solidworks, and simulating the front study by optical software TracePro.Using four-color mixing with self-developed formula to avoid the present white light emitting diode patent, and the four-color grains are Red, Green, Blue and adding Y to modify the overall quality of the mixed light.The phosphorproduceSteabler-Wronsk hardly in the high temperatureas compared tofour-color mixing.Using four-color mixing to producehigher color rendering index than yellow phosphor.Series-parallel array of grain arrangement adopted to achieve the high demand for uniformity, while simplifying the design conditions by a certain current instead of the general mixed light-driven complex driver circuit,the completion of the mixing module using integrating sphere, light spectrum on the spectrophotometer, optical power, color coordinates values, such as mixing uniformity measurements.The chromaticity coordinates errors after complete results of the mixing module measurement and simulation can be controlled under (0.01x, 0.01y).

Numerical Analysis for Thermal Performance of High Power Multi-Chip LED Packaging

2010 ◽  
Vol 139-141 ◽  
pp. 1433-1437
Author(s):  
Kai Lin Pan ◽  
Jiao Pin Wang ◽  
Jing Liu ◽  
Guo Tao Ren
Keyword(s):  
High Power ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Three Dimensional ◽  
Junction Temperature ◽  
Light Emitting ◽  
Die Attach ◽  
Dissipation Model ◽  
Key Issues

Heat dissipation and cost are the key issues for light-emitting diode (LED) packaging. In this paper, based on the thermal resistance network model of LED packaging, three-dimensional heat dissipation model of high power multi-chip LED packaging is developed and analyzed with the application of finite element method. Temperature distributions of the current multi-chip LED packaging model are investigated systematically under the different materials of the chip substrate, die attach, and/or different structures of the heat sink and fin. The results show that the junction temperature can be decreased effectively by increasing the height of the heat sink, the width of the fin, and the thermal conductivity of the chip substrate and die attach materials. The lower cost and higher reliability for LED source can be obtained through reasonable selection of materials and structure parameters of the LED lighting system.

Research Progress on Packaging Thermal Management Techniques of High Power LED

2011 ◽  
Vol 347-353 ◽  
pp. 3989-3994 ◽  
Author(s):  
Jian Xin Zhang ◽  
Ping Juan Niu ◽  
Da Yong Gao ◽  
Lian Gen Sun
Keyword(s):  
Thermal Management ◽  
High Power ◽  
Thermal Power ◽  
Light Output ◽  
Life Time ◽  
Thermal Design ◽  
Junction Temperature ◽  
Research Progress ◽  
High Heat Flux ◽  
High Power Led

In order to dominate the lighting market, LED needs more electrical power to be driven for higher brightness, thereby increasing thermal power dissipation, which contributes to a high heat flux of 85W/cm2 within a recent typical high power LED chip. And the junction temperature has direct influence upon the light output efficiency, device life time, emitting wavelength and reliability of LED. Therefore, effective removal of heat to maintain a safe junction temperature is the key to meet the future flux per LED requirements. Compared with other individual thermal resistances along the thermal path, thermal design for much lower packaging thermal resistance is more critical to improve the performances of LED. In this paper, major present technical researches on packaging thermal management were analyzed for high power LED, and the advantages and shortcomings of these techniques were respectively summarized. Besides, some suggestions were provided for further research in this area.

Compact Measurement of the Optical Power in High-Power LED Using a Light-Absorbent Thermal Sensor: A Recent Study

2021 ◽  
pp. 151-164
Author(s):  
Youyoung Kim ◽  
Jae-Young Joo ◽  
Jong-Min Kim ◽  
Sun-Kyu Lee
Keyword(s):  
High Power ◽  
Optical Power ◽  
Thermal Sensor ◽  
High Power Led

scholarly journals Analyzing Thermal Module Developments and Trends in High-Power LED

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Jung-Chang Wang
Keyword(s):  
Life Cycle ◽  
High Power ◽  
Light Emitting Diode ◽  
Junction Temperature ◽  
Light Emitting ◽  
Consumer Electronic ◽  
High Power Led ◽  
Fin Thickness ◽  
Good Agreement ◽  
Indoor And Outdoor

The solid-state light emitting diode (SSLED) has been verified as consumer-electronic products and attracts attention to indoor and outdoor lighting lamp, which has a great benefit in saving energy and environmental protection. However, LED junction temperature will influence the luminous efficiency, spectral color, life cycle, and stability. This study utilizes thermal performance experiments with the illumination-analysis method and window program (vapour chamber thermal module, VCTM V1.0) to investigate and analyze the high-power LED (Hi-LED) lighting thermal module, in order to achieve the best solution of the fin parameters under the natural convection. The computing core of the VCTM program employs the theoretical thermal resistance analytical approach with iterative convergence stated in this study to obtain a numerical solution. Results showed that the best geometry of thermal module is 4.4 mm fin thickness, 9.4 mm fin pitch, and 37 mm fin height with the LED junction temperature of 58.8°C. And the experimental thermal resistances are in good agreement with the theoretical thermal resistances; calculating error between measured data and simulation results is no more than ±7%. Thus, the Hi-LED illumination lamp has high life cycle and reliability.

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