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An OLED Taillight Revolution: From Point Light Sources to Segmented Area Light Sources
摘要： OLEDs have been applied in automotive taillamp applications since 2016, and as they overcome their biggest obstacles—including reliability and cost—they are ready for a larger rollout.
关键词： automotive lighting,taillight,reliability,cost,OLED
更新于2025-09-11 14:15:04
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Investigation of Current-Driven Degradation of 1.3 μm Quantum-Dot Lasers Epitaxially Grown on Silicon
摘要： This work investigates the degradation processes affecting the long-term reliability of 1.3 μm InAs quantum-dot lasers epitaxially grown on silicon. By submitting laser samples to constant-current stress, we were able to identify the physical mechanisms responsible for the optical degradation. More specifically, the samples (i) exhibited a gradual increase in threshold current, well correlated with (ii) a decrease in sub-threshold emission, and (iii) a decrease in slope efficiency. These variations were found to be compatible with a diffusion process involving the propagation of defects toward the active region of the device and the subsequent decrease in injection efficiency. This hypothesis was also supported by the increase in the defect-related current conduction components exhibited by the electrical characteristics, and highlights the role of defects in the gradual degradation of quantum dot laser diodes. Electroluminescence measurements were used to provide further insight in the degradation process.
关键词： silicon photonics,semiconductor defects,degradation,reliability,Quantum dots,laser diodes
更新于2025-09-11 14:15:04
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AIP Conference Proceedings [AIP Publishing ADVANCES IN BASIC SCIENCE (ICABS 2019) - Bahal, India (7–9 February 2019)] ADVANCES IN BASIC SCIENCE (ICABS 2019) - Profit analysis of a uni-directional and non revertible 1+1 protection switching scheme in optical communication process
摘要： The present paper examines availability and profit analysis of a system comprising four optical lines out of which two are operative (working paths) and the other two are hot-standby (protection paths). Each working line has its own hot standby. On the failure of the working path, signal is received from its own protection path and the failed unit is gone under repair immediately by a repairman. If a working path and its corresponding protection path both get failed then system is said to be failed. The system is analyzed by making use of regenerative point technique. Various measures of system effectiveness as well as expression for finding the profit have been obtained.
关键词： 1+1 Protection Scheme,availability,reliability,profit analysis
更新于2025-09-11 14:15:04
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Mission Profile-Oriented Control for Reliability and Lifetime of Photovoltaic Inverters
摘要： With the aim to increase the competitiveness of solar energy, the high reliability of Photovoltaic (PV) inverters is demanded. In PV applications, the inverter reliability and lifetime are strongly affected by the operating condition that is referred to as the mission profile (i.e., solar irradiance and ambient temperature). Since the mission profile of PV systems is location-dependent, the inverter reliability performance and lifetime can vary considerably in practice. That is, from the reliability perspective, PV inverters with the same design metrics (e.g., component selection) may become over- or under-designed under different mission profiles. This will increase the overall system cost, e.g., initial cost for over-designed cases and maintenance cost for under-designed cases, which should be avoided. This paper thus explores the possibility to adapt the control strategies of PV inverters to the corresponding mission profiles. With this, similar reliability targets (e.g., component lifetime) can be achieved even under different mission profiles. Case studies have been carried out on PV systems installed in Denmark and Arizona, where the lifetime and the energy yield are evaluated. The results reveal that the inverter reliability can be improved by selecting a proper control strategy according to the mission profile.
关键词： capacitor,reliability,lifetime,PV inverters,mission profile,power device,control
更新于2025-09-11 14:15:04
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White LEDs With High Optical Consistency Packaged Using 3D Ceramic Substrate
摘要： Packaging efficiency and optical performances are important indexes for white light-emitting diodes (WLEDs) packaging. In this letter, wafer-level WLEDs packaging were presented by printing phosphor on three-dimensional (3D) ceramic substrate to improve packaging efficiency and optical consistency. The 3D ceramic substrate was prepared by repeatedly electroplating copper cups on the planar direct plated copper (DPC) ceramic substrate. The phosphor concentration was adjusted to realize natural white light. The fabrication errors of the 3D ceramic substrate and the optical performances of WLED modules were analyzed to evaluate the optical consistency of the WLED modules packaged by using 3D ceramic substrate. Consequently, the fabrication errors of 3D ceramic substrate are less than 1%. When the phosphor concentration was set at 12.5 wt%, the packaged LEDs achieve a natural white light with luminous efficiency (LE) of 94.55 lm/W, correlated color temperature (CCT) of 5915 K, and chromaticity coordinate of (0.3166, 0.3345). The WLED modules exhibit small standard deviations in LE (1%), color rendering index (1%), correlated color temperature (98 K), and high reliability. The results indicate that the WLEDs packaged using 3D ceramic substrate have excellent optical consistency.
关键词： direct plated copper (DPC) ceramic substrate,optical performance,White light-emitting diodes (WLEDs),LED packaging,reliability
更新于2025-09-11 14:15:04
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Reliability Characterization and Modelling of High Speed Ge Photodetectors
摘要： Understanding the origin and protocols to induce performance degradations of silicon photonics high speed photodetector represent a major issue for the qualification of the reliability of these devices. Using advanced characterization technics, it is shown that the dark current, the photonic current and the cut-off frequency of the photodiode can be degraded during voltage stress of 106 s, which could ultimately induce some significant device performance drift and failure. An explanation of these degradations is presented based on both electrical observed characterization degradations of both dark current and responsivity can indeed be modeled by a single carrier lifetime degradation, attributed to an impacting an increase of the surface recombination rate, unexpected in the this model are photocurrent. The results obtained with experimentally confirmed by extracting the activation energy of the dark current, before and after stress. The improved physical understanding of the degradation is expected to lead to shorter test protocols for silicon photonics devices.
关键词： carrier lifetime electrical characterization,Silicon photonics,activation energy,Ge photodetectors reliability
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE 69th Electronic Components and Technology Conference (ECTC) - Las Vegas, NV, USA (2019.5.28-2019.5.31)] 2019 IEEE 69th Electronic Components and Technology Conference (ECTC) - Assessment of Accelerometer Versus LASER for Board Level Vibration Measurements
摘要： The ongoing trend to deploy ICs in more complex and harsher applications, entails precise evaluation of solder joint reliability of components subjected to vibration loads. For this, a good understanding of the PCB vibrational motion during a board level vibration test is essential. This can only be achieved by a well characterized vibration test setup. The vibration motion can be recorded by using a contact-based measurement approach, using an accelerometer, or a contactless measurement configuration, i.e. using a Laser Doppler Vibrometer (LDV). This paper evaluates both measurement techniques by recording the PCB dynamic response, i.e. the resonance frequency and peak-to-peak displacement, in a board level vibration test set up. Bare and assembled printed circuit boards (PCBs) are investigated using different PCB form factors and package outlines (Wafer Level Chip Scale Package (WLCSP) and Ball Grid Array (BGA)), showing that LDV enables better lateral resolution and a more accurate measurement solution. Especially when the weight of the accelerometer cannot be neglected compared to the weight of the component on the PCB. An accelerometer is shown to perturb the PCB vibration motion. It is found that depending upon the test objectives and PCB electronic system involved, both techniques can be used as complementary to one another. The accelerometer weight may give rise to substantial modification of vibration response which can be used to simulate the presence of a component on a bare PCB. In addition, both methods are expected to recognize the same trends when e.g. studying the environmental impact during vibration tests. Finally, the experimental observations are also confirmed using a Finite Element Model (FEM).
关键词： board level reliability,LASER Doppler Vibrometer,Wafer Level Chip Scale Package,vibration test,modal analysis,PCB dynamic response
更新于2025-09-11 14:15:04
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Long-Term Behavior of Hydrogenated Amorphous Silicon Thin-Film Transistors Covered With Color Filters for Use in Optical Sensors
摘要： This work investigates the long-term behavior of photo thin-film transistors (TFTs) that are covered with color filters and based on hydrogenated amorphous silicon (a-Si:H) technology. Based on the electrical characteristics and the optical responses of these TFTs as measured under different stress conditions, a new method for driving a photo TFT with a negative gate-source voltage is proposed to suppress the degradation of the photocurrent. The effectiveness of the newly proposed method is verified using our previously developed white-light photocurrent gating (WPCG) structure, the measurement of photocurrents, and the established models of red, green, and blue photo TFTs. An accelerated lifetime test of the fabricated circuit was carried out at 70 ?C and under the illumination of ambient light for 504 hours, demonstrating that the proposed method improves the long-term reliability of optical sensors.
关键词： optical sensor,Hydrogenated amorphous silicon thin-film transistor,long-term reliability
更新于2025-09-11 14:15:04
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Comparison and perspective of conventional and LED lighting for photobiology and industry applications
摘要： Electrical lighting systems benefit the plant photobiology field in numerous ways, but comprehensive knowledge of external environment factors is required, rather than choosing the latest lighting technology.
关键词： electrical lighting,LEDs,HPS,reliability,photobiology
更新于2025-09-11 14:15:04
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Heat degradation of sputter-deposited Cu(In,Ga)Se2 solar cells and modules: Impact of processing conditions and bias
摘要： We report accelerated heat degradation studies on fully encapsulated Cu(In,Ga)Se2 modules as a function of film growth parameters, in particular back contact selenization (preeSe), as well as the impact of bias (light/voltage) during heat degradation. We show that pre-Se conditions have a profound effect on the heat stability of the device, whereby reduced preeSe, while increasing initial efficiency, results in strong heat degradation, driven by a combination of reduced space-charge region and reduced minority carrier lifetime (as evident from external quantum efficiency measurements) in the light-soaked state and resulting in strong degradation of short-circuit current. This is also accompanied by a stronger increase in the shallow acceptor concentration (as measured by capacitance-voltage profiling) in the degraded state, suggesting that the SeeCu divacancy complex (VSe-VCu) is likely responsible. In this case, appearance of a high concentration of deep acceptor states accompanies increased shallow doping upon light-soaking, with the former reducing bulk lifetime and the latter further affecting electron collection due to narrow depletion width. This result suggests that bulk structural properties of the absorber film are strongly impacted by the back contact selenization conditions, making the film more susceptible to heat degradation. In the second part of this paper we show that electrical or light bias during heat exposure reduces degradation, in particular almost fully eliminating the above short-circuit current loss. This is a surprising result as usually the positive effects of bias are attributed to interfacial changes, while our results demonstrate that bulk properties can be improved as well.
关键词： Absorber,Interface,Defects,Thin film solar cell,Heat degradation,Reliability,Light soaking,Copper indium gallium selenide
更新于2025-09-11 14:15:04