Uncover the Degradation Science of Silicone Under the Combined Temperature and Humidity Conditions

Singh, Preetpal; Tan, Cher Ming

doi:10.1109/access.2017.2778289

Cited by 18 publications

(16 citation statements)

References 33 publications

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“…Destructive analysis of the LED encapsulation and molding parts revealed that cracks were observed in both components. However, the cause of such cracks in both encapsulation and molding parts of the LED package were different as reported by Singh et.al [33,34].…”

Section: Failure Analysis Of Leds At On State During Met Testmentioning

confidence: 77%

“…The discoloration in the molding part and encapsulation of the white LEDs were found to be more severe as compared to blue LEDs due possibly to the excess heat generated by the phosphor layer during the light conversion process [33]. Destructive analysis of the LED encapsulation and molding parts revealed that cracks were observed in both components.…”

Section: Failure Analysis Of Leds At On State During Met Testmentioning

confidence: 95%

“…To further understand the root cause of this degradation, optical microscope imaging was used to observe changes in LEDs after every 24 hours of testing. The optical images revealed heavy discoloration of the LEDs which was suspected to be in the silicone encapsulation and molding part of the LEDs as shown in Figure 4 [33].…”

Section: Failure Analysis Of Leds At On State During Met Testmentioning

confidence: 99%

“…Degradation Analysis of Silicone as Encapsulation and Molding Material in High Power LEDs DOI: http://dx.doi.org/10.5772/intechopen.107956 encapsulation of the blue LEDs. The depth of cracks on the encapsulant was quite minimal where average depth was around 3 μm for blue LEDs and that for white degraded LED encapsulant, it is almost negligible and not able to measure using optical microscope [33]. Scanning Electron Microscopy (SEM) was employed to further investigate the surface of the blue and white degraded LED's encapsulant and compared to a fresh LED encapsulant.…”

Section: Analysis Of Encapsulant Degradationsmentioning

confidence: 99%

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Degradation Analysis of Silicone as Encapsulation and Molding Material in High Power LEDs

Shabir¹,

Tan²

2023

Light-Emitting Diodes - New Perspectives

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Applications of LEDs have increased significantly, and increasing outdoor applications are observed. Some outdoor applications require high reliability as their failure can lead to hazardous consequences. Examples are their applications in automotive, street lamp lighting etc. To ensure the reliability of LEDs in outdoor applications, reliability test that include humidity on the LEDs must be done. However, it is found that accelerated life test of LEDs at high humidity level cannot be extrapolated to standard condition of lower humidity as the mechanism of degradation depends critically on humidity level. In fact, the degradation of LEDs in outdoor applications is mainly due to the degradation of their encapsulation and housing materials (or called packaging material as a whole) instead of the semiconductor chip itself. The decrease in lumen is the results of crack and discoloration of the LED packaging material. Detail understanding of the failure physics of the packaging material for LED under humidity is needed for extrapolation performed at accelerated stress condition so that LED luminary reliability can be predicted. This chapter reviews the different types of degradation physics of the packaging material using ab-initio simulation with excellent verification from experiments. The method of extrapolation is therefore derived from the physics-based model after detailed understanding of the degradation physics of LEDs. The model also provides strategy for industry to prolong the usage of LEDs in outdoor applications, either through materials or operating conditions selection.

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Section: Failure Analysis Of Leds At On State During Met Testmentioning

confidence: 77%

Section: Failure Analysis Of Leds At On State During Met Testmentioning

confidence: 95%

Section: Failure Analysis Of Leds At On State During Met Testmentioning

confidence: 99%

Section: Analysis Of Encapsulant Degradationsmentioning

confidence: 99%

See 2 more Smart Citations

Degradation Analysis of Silicone as Encapsulation and Molding Material in High Power LEDs

Shabir¹,

Tan²

2023

Light-Emitting Diodes - New Perspectives

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“…A possible reason is cited as von Mises stress at the interface due to hygroscopic stress caused by moisture ingression over time [34]. It is postulated that higher relative humidity levels cause further moisture inception leading to greater degrees of delamination which has been shown to be a mechanism for white LED light degradation [35].…”

Section: Degradation Investigation By Physical Analysesmentioning

confidence: 99%

A Practical Degradation Based Method to Predict Long-Term Moisture Incursion and Color Change in High Power LEDs

Law

Lim

2018

IEEE Photonics J.

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The effect of relative humidity on LEDs and how the moisture incursion is associated to the color shift is studied. This paper proposes a different approach to describe the lumen degradation of LEDs due to the long-term effects of humidity. Using the lumen degradation data of different types of LEDs under varying conditions of relative humidity, a humidity based degradation model (HBDM) is developed. A practical estimation method from the degradation behaviour is proposed to quantitatively gauge the effect of moisture incursion by means of a humidity index. This index demonstrates a high correlation with the color shift indicated by the LED's yellow to blue output intensity ratio. Physical analyses of the LEDs provide a qualitative validation of the model, which provides good accuracy with longer periods of moisture exposure. The results demonstrate that the HBDM is an effective indicator to predict the extent of the long-term impact of humidity and associated relative color shift.

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Introduction

Tan

Singh

2023

Reliability and Failure Analysis of High-Power LED Packaging

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Uncover the Degradation Science of Silicone Under the Combined Temperature and Humidity Conditions

Cited by 18 publications

References 33 publications

Degradation Analysis of Silicone as Encapsulation and Molding Material in High Power LEDs

Degradation Analysis of Silicone as Encapsulation and Molding Material in High Power LEDs

A Practical Degradation Based Method to Predict Long-Term Moisture Incursion and Color Change in High Power LEDs

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