In this paper,high-power LED with many integrated chips is used as thermal resistance analysis research object, and we do thermal resistance testing technology research on it. We put forward the thermocouple point con...In this paper,high-power LED with many integrated chips is used as thermal resistance analysis research object, and we do thermal resistance testing technology research on it. We put forward the thermocouple point contact test method. According to the principle that LED forward voltage changes with temperature,LED heat sink to surface temperature distribution is studied directly in the test,and then we analyze the thermal resistance of high-power LED with many integrated chips when its secondary packaging is introduced. This method makes the measurement of thermal resistance of LED more rapid and convenient. It provides an effective assessment method for the analysis of high power LED device design and engineering application.展开更多
A series of high phase purity blue light excitable yellow-emitting LaSiN:xCephosphors were synthesized by the high temperature solid state reactions method. The structure and luminescent properties were investigated. ...A series of high phase purity blue light excitable yellow-emitting LaSiN:xCephosphors were synthesized by the high temperature solid state reactions method. The structure and luminescent properties were investigated. The phase structure was studied by means of X-ray diffraction, structures refinements and energy dispersive X-ray spectroscopy. The phosphors effectively excited by the light of450 nm and show intense yellow emission at 535 nm with FWHM of 115 nm corresponding to the5 d →~2 Fand 5 d →~2 Ftransitions of Ce. In addition,the optimized LaSiN:0.14 Ceexhibits a weak thermal quenching, which remains 98.2% of the initial emission intensity when heated to 200 ℃,the thermal quenching properties exhibit a modest decline when the temperature returned to room temperature. The above results indicate that LaSiN:Cecan be regarded as a high promising phosphor for applications in high power white-light LED.展开更多
This paper summarizes different kinds of heat sinks on the market for high power LED lamps. Analysis is made on the thermal model of LED, PCB and heat sink separately with a simplified mode provided. Two examples of s...This paper summarizes different kinds of heat sinks on the market for high power LED lamps. Analysis is made on the thermal model of LED, PCB and heat sink separately with a simplified mode provided. Two examples of simulation are illustrated as a demonstration for the thermal simulation as guidance for LED lamp design.展开更多
The package and system level temperature and thermal stress distributions of 10 W light emitting diode （LED） with 4 chips and 100 W LED with 100 chips were investigated using finite element analysis. The chips were ...The package and system level temperature and thermal stress distributions of 10 W light emitting diode （LED） with 4 chips and 100 W LED with 100 chips were investigated using finite element analysis. The chips were arranged on a Si sheet which is soldered on the copper/diamond composite slug with very high conductivity. The experimental results show that the maximal temperature appears in the chips of both two high power LEDs packages. Compared with the 10 W LEDs package with 4 chips array, the heat issue caused by stacking and coupling of the heat in 100 W LEDs package with 100 chips array is more serious. The chip temperature in the center of the array is much higher, and it decreases with the distance between the chip and the center of LEDs increases. Great thermal stress lies between the chips and the solder, which will reduce the reliability of the package.展开更多
This paper provides an analytical approach to determine the optimum pitch by utilizing a thermal resistance network, under the assumption of constant luminous efficiency. This work allows an LED array design which is ...This paper provides an analytical approach to determine the optimum pitch by utilizing a thermal resistance network, under the assumption of constant luminous efficiency. This work allows an LED array design which is mounted on a printed circuit board （PCB） attached with a heat sink subject to the natural convection cooling. Being validated by finite element （FE） models, the current approach can be shown as an effective method for the determination of optimal component spacing in an LED array assembly for SSL.展开更多
基金Sponsored by the Heilongjiang Provincial Project(Grant No.12511121)the Harbin City Innovation Talent Project(Grant No.2011RFXXG019)the National Science and Technology Support Project(Grant No.2012BAH28F02)
文摘In this paper,high-power LED with many integrated chips is used as thermal resistance analysis research object, and we do thermal resistance testing technology research on it. We put forward the thermocouple point contact test method. According to the principle that LED forward voltage changes with temperature,LED heat sink to surface temperature distribution is studied directly in the test,and then we analyze the thermal resistance of high-power LED with many integrated chips when its secondary packaging is introduced. This method makes the measurement of thermal resistance of LED more rapid and convenient. It provides an effective assessment method for the analysis of high power LED device design and engineering application.
基金Project supported by the National Basic Research Program of China(2014CB643801)
文摘A series of high phase purity blue light excitable yellow-emitting LaSiN:xCephosphors were synthesized by the high temperature solid state reactions method. The structure and luminescent properties were investigated. The phase structure was studied by means of X-ray diffraction, structures refinements and energy dispersive X-ray spectroscopy. The phosphors effectively excited by the light of450 nm and show intense yellow emission at 535 nm with FWHM of 115 nm corresponding to the5 d →~2 Fand 5 d →~2 Ftransitions of Ce. In addition,the optimized LaSiN:0.14 Ceexhibits a weak thermal quenching, which remains 98.2% of the initial emission intensity when heated to 200 ℃,the thermal quenching properties exhibit a modest decline when the temperature returned to room temperature. The above results indicate that LaSiN:Cecan be regarded as a high promising phosphor for applications in high power white-light LED.
文摘This paper summarizes different kinds of heat sinks on the market for high power LED lamps. Analysis is made on the thermal model of LED, PCB and heat sink separately with a simplified mode provided. Two examples of simulation are illustrated as a demonstration for the thermal simulation as guidance for LED lamp design.
基金Funded by the High-Tech Research and Development Program of China (No. 2008AA03Z505)
文摘The package and system level temperature and thermal stress distributions of 10 W light emitting diode （LED） with 4 chips and 100 W LED with 100 chips were investigated using finite element analysis. The chips were arranged on a Si sheet which is soldered on the copper/diamond composite slug with very high conductivity. The experimental results show that the maximal temperature appears in the chips of both two high power LEDs packages. Compared with the 10 W LEDs package with 4 chips array, the heat issue caused by stacking and coupling of the heat in 100 W LEDs package with 100 chips array is more serious. The chip temperature in the center of the array is much higher, and it decreases with the distance between the chip and the center of LEDs increases. Great thermal stress lies between the chips and the solder, which will reduce the reliability of the package.
文摘This paper provides an analytical approach to determine the optimum pitch by utilizing a thermal resistance network, under the assumption of constant luminous efficiency. This work allows an LED array design which is mounted on a printed circuit board （PCB） attached with a heat sink subject to the natural convection cooling. Being validated by finite element （FE） models, the current approach can be shown as an effective method for the determination of optimal component spacing in an LED array assembly for SSL.
