Conference Paper

Humidity Effect on the Degradation of Packaged Ultra-bright White LEDs

Sch. of EEE, Nanyang Technol. Univ., Singapore, Singapore
DOI: 10.1109/EPTC.2008.4763548 Conference: Electronics Packaging Technology Conference, 2008. EPTC 2008. 10th
Source: IEEE Xplore

ABSTRACT Many ultra-bright light-emitting diodes (LEDs), especially the white LEDs, are being actively developed for solid-state lighting and many other commercial applications. Hence, it is important to evaluate and understand the failure mechanisms that affect the performance characteristics and lifetimes of these new LEDs. This study concerns the humidity effect on the degradation of GaN-based packaged white LEDs. Under the accelerated humidity test, the LEDs showed a degradation of optical output. With the mixture statistical distribution analysis method, it is noted that the luminous flux degradation of the packaged white LEDs is dependent on more than two failure mechanisms. Two of the failure mechanisms are observed to follow the lognormal distribution. With detailed spectrum analysis and by employing the parameters extraction method, one of the two failure mechanisms that follow the lognormal distribution is observed to be caused by chip related failure due to the accumulated moisture in the encapsulation. For the other failure mechanism, phosphor degradation is noted to be the primary cause.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Manufacturing companies face frequently changing market demands, time-to-market pressure, continuously emerging new technologies and global competition. To quick respond to ever-changing environment, the intra-enterprise integration of key technology applications is one of the fundamental requirements of the management and supervisory control systems at plant level. This paper presents an event-driven service oriented framework within which main services provided by manufacturing systems at different levels can be effectively managed in a holistic manner. The framework is derived from the analysis of fundamental requirements of three key services of manufacture systems, namely DRAM (dynamic resource allocation and management), RCAR (real-time control and auto-recovery), PMDP (performance monitoring, diagnosis and prognosis). The conceptual designs of the main components of the framework are presented, which include information data model, event triggering and message exchange mechanism as well as Shop-floor Service Bus that enables service oriented architecture.
    01/2009; DOI:10.1109/AIM.2009.5229981
  • [Show abstract] [Hide abstract]
    ABSTRACT: Reliability issues in solid state lighting (SSL) devices based on light emitting diodes (LED) is of major concern as it is a limiting factor to promote these optoelectronic devices for general lighting purposes. This postulate is even truer for high power devices in which high current and thus high thermal load are involved. In order to increase reliability and lighting efficacy, LED designs related to thermal management are evolving parallel to LED research and development. However there are still some issues mainly related to the degradation of LED’s constituents with time involving a faster decay of the lightning efficacy. In order to increase reliability of SSL devices, components presenting self-repairing properties could be implemented. In this review we will first briefly expose the state of the art on inorganic semiconductor based LED research and development, trends and challenges that lead to an increase of lighting efficiency. In a second part the different failure mode occurring for SSL devices have been compiled highlighting what are the main mechanism influencing and limiting LED reliability. Strong from this knowledge, in the last part, self-healing concepts will be proposed to further improve LED’s reliability.
    Microelectronics Reliability 01/2012; 52(1):71-89. DOI:10.1016/j.microrel.2011.08.013 · 1.21 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The increasing demand for light emitting diodes (LEDs) has been driven by a number of application categories, including display backlighting, communications, medical services, signage, and general illumination. The construction of LEDs is somewhat similar to microelectronics, but there are functional requirements, materials, and interfaces in LEDs that make their failure modes and mechanisms unique. This paper presents a comprehensive review for industry and academic research on LED failure mechanisms and reliability to help LED developers and end-product manufacturers focus resources in an effective manner. The focus is on the reliability of LEDs at the die and package levels. The reliability information provided by the LED manufacturers is not at a mature enough stage to be useful to most consumers and end-product manufacturers. This paper provides the groundwork for an understanding of the reliability issues of LEDs across the supply chain. We provide an introduction to LEDs and present the key industries that use LEDs and LED applications. The construction details and fabrication steps of LEDs as they relate to failure mechanisms and reliability are discussed next. We then categorize LED failures into thirteen different groups related to semiconductor, interconnect, and package reliability issues. We then identify the relationships between failure causes and their associated mechanisms, issues in thermal standardization, and critical areas of investigation and development in LED technology and reliability.
    Microelectronics Reliability 05/2012; 52(5). DOI:10.1016/j.microrel.2011.07.063 · 1.21 Impact Factor

Preview (2 Sources)

Available from