Analysis of ZnO Thin Film as Thermal Interface Material for High Power Light Emitting Diode Application

2016 ◽  
Vol 138 (1) ◽  
Author(s):  
S. Shanmugan ◽  
O. Zeng Yin ◽  
P. Anithambigai ◽  
D. Mutharasu
Keyword(s):  
Thin Film ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Light Emitting Diode ◽  
Thermal Interface Material ◽  
Zno Thin Film ◽  
Thermal Interface ◽  
Light Emitting ◽  
Thermal Paste ◽  
Cu Substrates

All solid-state lighting products produce heat which should be removed by use of a heat sink. Since the two mating surfaces of light emitting diode (LED) package and heat sink are not flat, a thermal interface material (TIM) must be applied between them to fill the gaps resulting from their surface roughness and lack of coplanarity. The application of a traditional TIM may squeeze out when pressure is applied to join the surfaces and hence a short circuit may result. To avoid such a problem, a thin solid film based TIM has been suggested. In this study, a zinc oxide (ZnO) thin film was coated on Cu substrates and used as the TIM. The ZnO thin film coated substrates were used as heat sink purposes in this study. The prepared heat sink was tested with 3 W green LED and the observed results were compared with the results of same LED measured at bare and commercial thermal paste coated Cu substrates boundary conditions. The influence of interface material thickness on total thermal resistance (Rth-tot), rise in junction temperature (TJ), and optical properties of LED was analyzed. A noticeable reduction in Rth-tot (5.92 K/W) as well as TJ (ΔTJ = 11.83 °C) was observed for 800 nm ZnO thin film coated Cu substrates boundary conditions when compared with bare and thermal paste coated Cu substrates tested at 700 mA. Change in TJ influenced the thermal resistance of ZnO interface material. Improved lux level and decreased correlated color temperature (CCT) were also observed with ZnO coated Cu substrates.

Thermal Resistance Analysis of High Power Light Emitting Diode Using Aluminum Nitride Thin Film-Coated Copper Substrates as Heat Sink

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
S. Shanmugan ◽  
D. Mutharasu
Keyword(s):  
Thin Film ◽  
Aluminum Nitride ◽  
Thermal Resistance ◽  
High Power ◽  
Heat Sink ◽  
Light Emitting Diode ◽  
Thermal Interface Material ◽  
Circuit Board ◽  
Light Emitting ◽  
Cu Substrate

AlN thin film was coated over Cu substrate (575 mm2) with 400 nm thickness using DC sputtering for thermal interface material (TIM) application. Aluminum Nitride (AlN)-coated Cu substrate (AlN/Cu) was used as a heat sink for 3-W green light emitting diode (LED). The thermal transient curve was recorded for given LED attached with bare Cu and AlN-coated Cu substrate at three different driving currents. LED attached on AlN/Cu showed the reduced raise in junction temperature (TJ) by 2.59 °C at 700 mA. The LED/TIM/AlN/Cu boundary condition was not supported to reduce the TJ. The total thermal resistance (Rth-tot) was reduced for AlN-coated Cu substrate at 350 mA. The thermal resistance between metal core printed circuit board and Cu substrate (Rth-b-hs) was also observed as low for AlN-coated Cu substrates compared with other boundary conditions measured at 700 mA. The observed results were supported for the use of AlN thin film as TIM in high power LEDs.

Thermal resistance of high power LED influenced by ZnO thickness and surface roughness parameter

2016 ◽  
Vol 33 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Shanmugan Subramani ◽  
Mutharasu Devarajan
Keyword(s):  
Thin Film ◽  
Surface Roughness ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Roughness Parameter ◽  
Junction Temperature ◽  
Zno Thin Film ◽  
Content Type ◽  
Cu Substrates

Purpose – The purpose of this research is to study the effect of thickness and surface properties of ZnO solid thin film for heat dissipation application in LED. Heat dissipation in electronic packaging can be improved by applying a thermally conductive interface material (TIM) and hence the junction temperature will be maintained. ZnO is one of the oxide materials and used as a filler to increase the thermal conductivity of thermal paste. The thickness of these paste-type material cannot be controlled which restricts the heat flow from the LED junction to ambient. The controlled thickness is only possible by using a solid thin-film interface material. Design/methodology/approach – Radio Frequency (RF)-sputtered ZnO thin film on Cu substrates were used as a heat sink for high-power LED and the thermal performance of various ZnO thin film thickness on changing total thermal resistance (R th-tot) and rise in junction temperature were tested. Thermal transient analysis was used to study the performance of the given LED. The influence of surface roughness profile was also tested on the LED performance. Findings – The junction temperature was high (6.35°C) for 200 nm thickness of ZnO thin film boundary condition when compared with bare Cu substrates. Consecutively, low R th-tot values were noticed with the same boundary condition. The 600 nm thickness of ZnO thin film exhibited high R th-tot and interface resistance than the other thicknesses. Bond Line Thickness of the interface material was influenced on the interface thermal resistance which was decreased with increased BLT. Surface roughness parameter showed an immense effect on thermal transport, and hence, low R th (47.6 K/W) value was noticed with low film roughness (7 nm) as compared with bare Cu substrate (50.8 K/W) where the surface roughness was 20.5 nm. Originality/value – Instead of using thermal paste, solid thin film ZnO is used as TIM and coated Cu substrates were used as a heat sink. The thickness can be controlled, and it is a new approach for reducing the BLT between the metal core printed circuit board and heat sink.

Reduction of Thermal Resistance and Optical Power Loss Using Thin-Film Light-Emitting Diode (LED) Structure

2015 ◽  
Vol 62 (11) ◽  
pp. 6925-6933 ◽  
Author(s):  
Huan Ting Chen ◽  
Yuk Fai Cheung ◽  
Hoi Wai Choi ◽  
Siew Chong Tan ◽  
S. Y. Hui
Keyword(s):  
Thin Film ◽  
Thermal Resistance ◽  
Power Loss ◽  
Light Emitting Diode ◽  
Optical Power ◽  
Light Emitting

Thermal conduction characteristics of silicone composites including ultrasonic-treated graphite

2021 ◽  
pp. 002199832110595
Author(s):  
Weontae Oh ◽  
Jong-Seong Bae ◽  
Hyoung-Seok Moon
Keyword(s):  
Thermal Conductivity ◽  
Ultrasonic Treatment ◽  
Thermal Conduction ◽  
Light Emitting Diode ◽  
Thermal Interface Material ◽  
Ultrasonic Power ◽  
Lighting System ◽  
Thermal Interface ◽  
Light Emitting ◽  
Inorganic Oxides

The microstructural change of graphite was studied after ultrasonic treatment of the graphite. When the graphite solution was treated with varying ultrasonic power and time, the microstructure changed gradually, and accordingly, the thermal conductivity characteristics of the composite containing the as-treated graphite was also different with each other. Thermal conductivity showed the best result in the silicone composite containing graphite prepared under the optimum condition of ultrasonic treatment, and the thermal conductivity of the composite improved proportionally along with the particle size of graphite. When the silicone composite was prepared by using a mixture of inorganic oxides and graphite rather than graphite alone, the thermal conductivity of the silicone composite was further increased. A silicone composite containing graphite was used for LED (light emitting diode) lighting system as a thermal interface material (TIM), and the temperature elevation due to heat generated, while the lighting was actually operated, was analyzed.

Packaging of High Power UV-LED Modules on Ceramic and Aluminum Substrates

2012 ◽  
Vol 2012 (1) ◽  
pp. 000225-000232 ◽  
Author(s):  
Marc Schneider ◽  
Benjamin Leyrer ◽  
Christian Herbold ◽  
Stefan Maikowske
Keyword(s):  
Thermal Resistance ◽  
Heat Sink ◽  
Input Power ◽  
Thermal Interface Material ◽  
Maximum Temperature ◽  
Thermal Interface ◽  
Uv Led ◽  
Forward Current ◽  
Water Cooler ◽  
Forced Air

An LED module consisting of 98 UV-LEDs with an emission wavelength of 395 nm placed on a ceramic substrate of 211 mm2 is presented. The module is cooled by a forced air heat sink as well as a high performance microstructured water cooler to lower the thermal resistance. For high thermal conductance a liquid metal as the thermal interface material between substrate and heat sink is used. With the forced air heat sink a maximum irradiance of 27.3 W/cm2 at a forward current of 700 mA and 220 W electrical input power was achieved. The microstructured water cooler enabled an almost doubling of the electrical input power (430 W) while maintaining the chip's maximum temperature. For a reduction of the module's thermal resistance a thick film process for aluminum sheet metal substrates was developed. A prototype LED module with 25 UV-LED chips on an area of 54 mm2 achieved a maximum optical power density of 31.6 W/cm2 at a forward current of 900 mA using a forced air heat sink. For an improved cooling of the LED chips a chip-on-heat sink-technology with embedded water cooling channels is developed to eliminate the thermal interface between substrate and heat sink.

Room temperature electroluminescence from arsenic doped p-type ZnO nanowires/n-ZnO thin film homojunction light-emitting diode

2014 ◽  
Vol 25 (4) ◽  
pp. 1955-1958 ◽  
Author(s):  
Hongwei Liang ◽  
Qiuju Feng ◽  
Xiaochuan Xia ◽  
Rong Li ◽  
Huiying Guo ◽  
...  
Keyword(s):  
Thin Film ◽  
Room Temperature ◽  
Light Emitting Diode ◽  
Zno Nanowires ◽  
Zno Thin Film ◽  
Light Emitting ◽  
P Type

Transparent and Photo-stable ZnO Thin-film Transistors to Drive an Active Matrix Organic-Light- Emitting-Diode Display Panel

2009 ◽  
Vol 21 (6) ◽  
pp. 678-682 ◽  
Author(s):  
Sang-Hee K. Park ◽  
Chi-Sun Hwang ◽  
Minki Ryu ◽  
Shinhyuk Yang ◽  
Chunwon Byun ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Light Emitting Diode ◽  
Zno Thin Film ◽  
Active Matrix ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light
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