Effect of Phosphor Encapsulant on the Thermal Resistance of a High-Power COB LED Module

Juntunen, Eveliina; Tapaninen, Olli; Sitomaniemi, Aila; Heikkinen, Ville

doi:10.1109/tcpmt.2013.2260796

Cited by 31 publications

(17 citation statements)

References 10 publications

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“…The structural details of the LED chips are neglected in the multi-domain model, since could not measure one chip only. Even so, following the procedure of Juntunen et al (Juntunen 2013), from the structure functions obtained by "ensemble measurement" of the LED array the thermal resistance was properly set. The luminous flux of a naked blue LED chip was calculated with the help of the phosphor layer model with the assumption that the phosphor layer properties were roughly the same as the custom phosphor layer properties.…”

Section: Structure Of Cob Devicementioning

confidence: 99%

“…There have been many studies published on modelling and simulation of different aspects of CoB (Chip on Board) LEDs. Some are dealing with thermal aspects only such as the paper by Juntunen et al (2013), but a publication by H. T. Chen et al (2015) describes a real multidomain simulation approach. In this paper a simple thermal resistance approach is used to represent the chips' thermal environment which, in our opinion is a too simple solution.…”

Section: Introductionmentioning

confidence: 99%

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Multi-Domain Characterization of Cob Leds

Hegedüs

Hantos

Németh

et al. 2019

PROCEEDINGS OF the 29th Quadrennial Session of the CIE

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In a recent European H2020 project on LED characterisation and modelling (Delphi4LED, www.delphi4LED.eu) the major target was to represent physical LED package types by their digital twins in form of multi-domain compact models. In this project a specific task was devoted to CoB LEDs. Phosphor converted white CoB LEDs are large area devices on a ceramic substrate of high thermal conductivity, with a few dozens of LED chips mounted, covered by a phosphor layer. Such devices represent real technical challenges both in terms of their physical measurement and modelling. In this paper we report on our work regarding measurement and modelling of such devices performed in the context of the aforementioned project.

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Section: Structure Of Cob Devicementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Multi-Domain Characterization of Cob Leds

Hegedüs

Hantos

Németh

et al. 2019

PROCEEDINGS OF the 29th Quadrennial Session of the CIE

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“…Based on this analysis, some researchers reported a much higher temperature inside silicone than the junction temperature of blue chip. The temperature inside the silicone volume varied from 195 °C to 316 °C [33]- [35], [26], depending on the LED products.…”

Section: Motivating Examplementioning

confidence: 99%

Rapid Degradation of Mid-Power White-Light LEDs in Saturated Moisture Conditions

Huang

Golubović²,

Koh

et al. 2015

IEEE Trans. Device Mater. Relib.

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Serious silicone carbonization has been reported in mid-power white light LEDs during highly-accelerated temperature and humidity stress test (HAST), even though the junction temperature of the LED chip is much lower than the critical temperature of silicone carbonization (300 °C). This paper presents a comprehensive investigation, through which, the effects of Joule heating and phosphor self-heating has been eliminated as main failure mechanisms. As a result, the over-absorption of blue lights by silicone bulk, is considered as the root cause for silicone carbonization. This is mainly due to the scattering effect of water particles inside the silicone materials, which can increase the silicone temperature significantly. Furthermore, finite element thermal simulation has also been performed, confirming the validity of failure mechanism.

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“…The LED has several advantages, such as low power dissipation and long term reliability. Thus it can replace the traditional light bulb for illumination [1][2]. But as the applying power to the LED is increased, the heat dissipation problem would reduce the efficiency dramatically [3][4].…”

Section: Introductionmentioning

confidence: 99%

A Novel High Power LED Module Design on Aluminum Board (COAB) by Packaging Multi-Die in both Series and Parallel

Lin¹,

Lin²

2016

Proceedings of the 2016 4th International Conference on Management, Education, Information and Control (MEICI 2016)

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To decrease the LED operating temperature this paper presents a novel high power LED COAB (Chip on Aluminum Board) bonding method, the heat dissipation performance was studied by packaging the multi-die in the combination of series and parallel. The trade-off parameters were the bonding distance and driving voltage. The dies were connected in a combination of 3 dies in series and 3 sets in parallel (3x3 square matrix pattern). If the separation distance of die bonding was 1.5mm, the temperatures on the top surface of center LED with driving voltage of 8 (9) Volts was 75.2 (90.5) ℃. On the other hand, if the separation distance reduced to 1.0mm with the driving voltage of 8 (9) Volts, then the temperatures at the top surface of center LED would be increased to 75.7 (115.2) ℃. Thus for the LEDs efficiency kept at 80％ of those at 25℃, the final choice of die bonding distance and driving voltage were 1.0mm and 8V, respectively.

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Effect of Phosphor Encapsulant on the Thermal Resistance of a High-Power COB LED Module

Cited by 31 publications

References 10 publications

Multi-Domain Characterization of Cob Leds

Multi-Domain Characterization of Cob Leds

Rapid Degradation of Mid-Power White-Light LEDs in Saturated Moisture Conditions

A Novel High Power LED Module Design on Aluminum Board (COAB) by Packaging Multi-Die in both Series and Parallel

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