scholarly journals Development and Validation of a Novel Setup for LEDs Lifetime Estimation on Molded Interconnect Devices

Instruments ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 28 ◽  
Author(s):  
Mahdi Soltani ◽  
Moritz Freyburger ◽  
Romit Kulkarni ◽  
Rainer Mohr ◽  
Tobias Groezinger ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Functional Integration ◽  
Consumer Electronics ◽  
Light Sources ◽  
Circuit Boards ◽  
Light Emitting ◽  
Compact Design ◽  
Long Term Behavior ◽  
Molded Interconnect Devices

Higher energy efficiency, more compact design, and longer lifetime of light-emitting diodes (LEDs) have resulted in increasing their market share in the lighting industry, especially in the industries of consumer electronics, automotive, and general lighting. Due to their robustness and reliability, LEDs have replaced conventional light sources, such as fluorescent lamps. Many studies are examining the reliability of LEDs as such or investigating their long-term behavior on standard printed circuit boards (PCB). However, the thermal performance of LEDs mounted on nonconventional substrates is still not explored enough. An interesting example for this is the molded interconnect devices (MID), which are well known for the great design freedom and the great potential for functional integration. These characteristics not only underline the main abilities of the MID technology, but also present some challenges concerning thermal management. The long-term behavior of LEDs on MID is still quite untapped and this prevents this technology from consolidating its existence. In this context, this work highlights a developed test setup aimed at investigating LEDs, mounted on molded interconnect devices, under combined stress conditions. The results of the reliability study, as well as the resulting lifetime model, are also illustrated and discussed.

scholarly journals Parametric Compact Thermal Models of Power LEDs

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1724 ◽  
Author(s):  
Marcin Janicki ◽  
Tomasz Torzewicz ◽  
Przemysław Ptak ◽  
Tomasz Raszkowski ◽  
Agnieszka Samson ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Light Emitting Diodes ◽  
Operating Conditions ◽  
Junction Temperature ◽  
Light Sources ◽  
Cold Plate ◽  
Circuit Boards ◽  
Thermal Models ◽  
Light Emitting ◽  
Main Factor

Light-emitting diodes are nowadays the most dynamically developing type of light sources. Considering that temperature is the main factor affecting the electrical and lighting parameters of these devices, thermal models are essential subcomponents of the multidomain models commonly used for simulation of their operation. The authors investigated white power light-emitting diodes soldered to Metal Core Printed Circuit Boards (MCPCBs). The tested devices were placed in a light-tight box on a cold plate and their cooling curves were registered for different diode heating current values and various preset cold plate temperatures. These data allowed the computation of optical and real heating power values and consequently the generation of compact thermal models in the form of Foster and Cauer RC ladders. This also rendered possible the analysis of the influence of the considered factors on the compact model element values and their parametrization. The resulting models yield accurate values of diode junction temperature in most realistic operating conditions and they can be easily included in multidomain compact models of power light emitting diodes.

scholarly journals Evaluation of printed-circuit boards materials for high temperature operation

2017 ◽  
Vol 2017 (HiTEN) ◽  
pp. 000057-000062
Author(s):  
Oriol Aviño-Salvado ◽  
Wissam Sabbah ◽  
Cyril Buttay ◽  
Hervé Morel ◽  
Pascal Bevilacqua
Keyword(s):  
High Temperature ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Physical Measurements ◽  
Epoxy Material ◽  
High Temperature Operation

ABSTRACT This article presents the long term (1000 h) behaviour of two printed-circuit board materials (Panasonic R1755V, a high-TG glass-epoxy composite and Arlon 85N, a polyimide-based laminate) stored at high temperature (190 °C). Tests are performed in air and in nitrogen atmospheres. Electrical and physical measurements are performed regularly (once per week). Almost no degradation is observed for both materials, when stored in nitrogen. On the contrary, the board stored in air show the consequences of ageing. This is especially true for the glass-epoxy material, which becomes unusable after 2 weeks, because of large swelling.

scholarly journals E-Watse in Africa: A Serious Threat to the Health of Children

2021 ◽  
Vol 18 (16) ◽  
pp. 8488
Author(s):  
Tamba S. Lebbie ◽  
Omosehin D. Moyebi ◽  
Kwadwo Ansong Asante ◽  
Julius Fobil ◽  
Marie Noel Brune-Drisse ◽  
...  
Keyword(s):  
Developing Countries ◽  
Printed Circuit Boards ◽  
Electrical Equipment ◽  
Developed Countries ◽  
Toxic Substances ◽  
Circuit Boards ◽  
Valuable Metals ◽  
Surrounding Areas ◽  
Informal Settings

Waste electronic and electrical equipment (e-waste) consists of used and discarded electrical and electronic items ranging from refrigerators to cell phones and printed circuit boards. It is frequently moved from developed countries to developing countries where it is dismantled for valuable metals in informal settings, resulting in significant human exposure to toxic substances. E-waste is a major concern in Africa, with large sites in Ghana and Nigeria where imported e-waste is dismantled under unsafe conditions. However, as in many developing countries, used electronic and electrical devices are imported in large quantities because they are in great demand and are less expensive than new ones. Many of these used products are irreparable and are discarded with other solid waste to local landfills. These items are then often scavenged for the purpose of extracting valuable metals by heating and burning, incubating in acids and other methods. These activities pose significant health risks to workers and residents in communities near recycling sites. E-waste burning and dismantling activities are frequently undertaken at e-waste sites, often in or near homes. As a result, children and people living in the surrounding areas are exposed, even if they are not directly involved in the recycling. While toxic substances are dangerous to individuals at any age, children are more vulnerable as they are going through important developmental processes, and some adverse health impacts may have long-term impacts. We review the e-waste situation in Africa with a focus on threats to children’s health.

Enhancement of luminous flux of InGaAlP-based low-power SMD LEDs using substrates with different thermal resistances

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Muna Ezzi Raypah ◽  
Shahrom Mahmud ◽  
Mutharasu Devarajan ◽  
Anoud AlShammari
Keyword(s):  
Low Power ◽  
Printed Circuit Boards ◽  
Thermal Characteristics ◽  
Input Power ◽  
Luminous Flux ◽  
Optical Parameters ◽  
Circuit Boards ◽  
Aluminum Phosphide ◽  
Content Type ◽  
Light Emitting

Purpose Optimization of light-emitting diodes’ (LEDs’) design together with long-term reliability is directly correlated with their photometric, electric and thermal characteristics. For a given thermal layout of the LED system, the maximum luminous flux occurs at an optimal electrical input power and can be determined using a photo-electro-thermal (PET) theory. The purpose of this study is to extend the application of the luminous flux equation in PET theory for low-power (LP) LEDs. Design/methodology/approach LP surface-mounted device LEDs were mounted on substrates of different thermal resistances. Three LEDs were attached to substrates which were flame-retardant fiberglass epoxy (FR4) and two aluminum-based metal core printed circuit boards (MCPCBs) with thermal conductivities of about 1.0 W/m.K, 2.0 W/m.K and 5.0 W/m.K, respectively. The conjunction of thermal transient tester and thermal and radiometric characterization of LEDs system was used to measure the thermal and optical parameters of the LEDs at a certain range of input current and temperature. Findings The validation of the extended application of the luminous flux equation was confirmed via a good agreement between the practical and theoretical results. The outcomes show that the optimum luminous flux is 25.51, 31.91 and 37.01 lm for the LEDs on the FR4 and the two MCPCBs, respectively. Accordingly, the stipulated maximum electrical input power in the LED datasheet (0.185 W) is shifted to 0.6284, 0.6963 and 0.8838 W between the three substrates. Originality/value Using a large number of LP LEDs is preferred than high-power (HP) LEDs for the same system power to augment the heat transfer and provide a higher luminous flux. The PET theory equations have been applied to HP LEDs using heatsinks with various thermal resistances. In this work, the PET theory luminous flux equation was extended to be used for Indium Gallium Aluminum Phosphide LP LEDs attached to the substrates with dissimilar thermal resistances.

An FPGA-based monitoring system for reliability analysis

2017 ◽  
Vol 2017 (NOR) ◽  
pp. 1-4
Author(s):  
Christian Johansson ◽  
Jonas Arwidson ◽  
Torbjörn Månefjord
Keyword(s):  
Monitoring System ◽  
Failure Rate ◽  
Hot Spots ◽  
Printed Circuit Boards ◽  
Operating Conditions ◽  
Circuit Boards ◽  
Flexible System ◽  
Long Term Storage ◽  
Term Storage

Abstract Electronics density continue to increase which impacts the power density and thermal hot spots on the printed circuit boards. The reliability and prediction of the electronics failure rate is often related to the thermal stress induced during different operating conditions at the board. To get information about the environmental conditions and to assist in the prediction of a product's failure rate a monitoring system could be used. This paper presents a temperature monitoring function implemented in an FPGA using VHDL. The proposed system is composed of a number of temperature sensors together with a non-volatile MRAM memory for long-term storage. The solution offers a flexible system that could be scaled to an arbitrary number of sensors and be adapted to any FPGA or processor technology. To verify the concept, a climate chamber was used to simulate a number of different environmental settings followed by a reading of the data logged.

scholarly journals PCB Origami: A Material-Based Design Approach to Computer-Aided Foldable Electronic Devices

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Yoav Sterman ◽  
Erik D. Demaine ◽  
Neri Oxman
Keyword(s):  
Printed Circuit Boards ◽  
Electronic Materials ◽  
Electronic Devices ◽  
Circuit Boards ◽  
Light Emitting ◽  
Printed Circuit ◽  
3D Objects ◽  
Evaluation Strategies ◽  
Embedded Electronics ◽  
User Guidance

Origami is traditionally implemented in paper, which is a passive material. This research explores the use of material with embedded electronics such as printed circuit boards (PCB) as the medium for origami folding to create an interactive folding experience and to generate foldable objects with added functionalities. PCBs are produced as 2D shapes. By folding PCB arrays, it is possible to create 3D objects that contain electronic functions. Conductivity, output devices (such as light emitting diodes) and microcontroller computation can create an interactive folding experience, for user guidance and verification of the folding. We call this approach and methodology PCB origami. The work presented in this paper describes two unique interaction and fabrication techniques for creating and folding electronic materials. We demonstrate prototypes and present verification/evaluation strategies for guiding the user through the folding process.

scholarly journals PCB Origami: A Material-Based Design Approach to Computer-Aided Foldable Electronic Devices

2013 ◽  
Author(s):  
Yoav Sterman ◽  
Erik D. Demaine ◽  
Neri Oxman
Keyword(s):  
Printed Circuit Boards ◽  
Electronic Materials ◽  
Electronic Devices ◽  
Homogeneous Material ◽  
Circuit Boards ◽  
Light Emitting ◽  
Printed Circuit ◽  
3D Objects ◽  
Evaluation Strategies ◽  
Embedded Electronics

Origami is traditionally implemented in paper of homogeneous material properties. This research explores the use of material with embedded electronics such as PCB (Printed Circuit Boards) as the medium for origami folding in order to create an interactive folding experience and to generate foldable objects with added functionalities. PCBs are produced as 2D shapes. By folding PCB arrays it is possible to create 3D objects that contain electronic functions. Conductivity, output devices (such as Light Emitting Diodes) and microcontroller computation can create an interactive folding experience, for user guidance and verification of the folding. We call this approach and methodology PCB Origami. The work presented in this paper describes two unique interaction and fabrication techniques for creating and folding electronic materials. We demonstrate prototypes and present verification/evaluation strategies for guiding the user through the folding process.

scholarly journals Thermal Analysis of the Factors Influencing Junction Temperature of LED Panel Sources

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3941 ◽  
Author(s):  
Krzysztof Baran ◽  
Antoni Różowicz ◽  
Henryk Wachta ◽  
Sebastian Różowicz ◽  
Damian Mazur
Keyword(s):  
Printed Circuit Boards ◽  
Junction Temperature ◽  
Light Sources ◽  
Simulation Studies ◽  
Thermal Coupling ◽  
Circuit Boards ◽  
Optical Efficiency ◽  
Panel Model ◽  
Computational Fluid Dynamics Cfd ◽  
Air Flow Velocity

Limiting junction temperature Tj and maintaining its low value is crucial for the lifetime and reliability of semi-conductive light sources. Obtaining the lowest possible temperature of Tj is especially important in the case of LED panels, where in a short distance there are many light sources installed, between which there occurs mutual thermal coupling. The article presents results of simulation studies connected with the influence of construction and ambient factors that influence the value of junction temperature of exemplary LED panel sources. The influence of radiator’s construction, printed circuit boards, as well as the influence of ambient factors, such as ambient temperature Ta and air flow velocity v were subjected to the analysis. Numerical calculations were done in the FloEFD software of the Mentor Graphics company, which is based on computational fluid dynamics (CFD). For construction of the LED thermal panel model the optical efficiency ηo and real thermal resistance Rthj-c were determined in a laboratory for the applied light sources.

Effect of fillers on the metallization of laser-structured polymer parts

2017 ◽  
Vol 37 (2) ◽  
pp. 151-161 ◽  
Author(s):  
Andreas J. Fischer ◽  
Steve Meister ◽  
Dietmar Drummer
Keyword(s):  
Functional Integration ◽  
Three Dimensional ◽  
Circuit Boards ◽  
Matrix Polymer ◽  
Glass Spheres ◽  
The Matrix ◽  
Inorganic Fillers ◽  
Processing Properties ◽  
Molded Interconnect Devices

Abstract Molded interconnect devices offer great potential as a substitute for circuit boards, especially regarding three-dimensional shaping and functional integration. Applying circuits to polymer substrates can be performed by means of LPKF laser direct structuring® (LDS). There, the matrix polymer is filled with a special metal additive, enabling laser activation and subsequent metallization. Important effects emerge from additional inorganic fillers inside the matrix polymer, e.g. the (thermo)mechanical behavior and the processing properties. In this work, the degree to which inorganic fillers affect the quality of metallization is investigated. An increase in the plating thickness was successfully achieved by adding varying amounts of talc platelets (diameter 7 μm) to a PA10T-based copolyamide filled with 4 and 8 wt% LDS additive, in contrast to poor metal deposition adding only LDS additive. Additionally, talc and glass spheres with a diameter of 50 μm were used, leading to unsatisfactory metallization results. To explain this behavior, adhering LDS particles were found on the talc platelets with a diameter of 7 μm on the surface of the laser-structured specimen. The talc platelets and glass spheres of 50 μm were not available in sufficient dimensions on the surface and thus led to worse plating results.

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