scholarly journals Universal synthesis of conductive liquid network in polymers enabling elastic printed circuit board technology

2021 ◽  
Author(s):  
Jiheong Kang ◽  
Wonbeom Lee ◽  
Hyunjun Kim ◽  
Inho Kang ◽  
Hongjun Park ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Acoustic Field ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
System Level ◽  
Large Strains ◽  
Stretchable Electronics ◽  
Electronic Components ◽  
Conductive Liquid ◽  
Printed Circuit

Abstract Stretchable electronics are considered next-generation electronic devices in a broad range of emerging fields, including soft robotics1,2, biomedical devices3,4, human-machine interfaces5,6, and virtual or augmented reality devices7,8. A stretchable printed circuit board (S-PCB) is a basic conductive framework for the facile assembly of system-level stretchable electronics with various electronic components. Since an S-PCB is responsible for electrical communications between numerous electronic components, the conductive lines in S-PCB should strictly satisfy the following features: (i) metallic conductivity, (ii) constant electrical resistance during dynamic stretching, and (iii) tough interface bonding with various components9. Despite recent significant advances in intrinsically stretchable conductors10,11,12, they cannot simultaneously satisfy the above stringent requirements. Here, we present a new concept of conductive liquid network-based elastic conductors. These conductors are based on unprecedented liquid metal particles assembled network (LMPNet) and an elastomer. The unique assembled network structure and reconfigurable nature of the LMPNet conductor enabled high conductivity, high stretchability, tough adhesion, and imperceptible resistance changes under large strains, which enabled the first elastic-PCB (E-PCB) technology. We synthesized LMPNet through an acoustic field-driven cavitation event in the solid state. When an acoustic field is applied, liquid metal nanoparticles (LMPnano) are remarkably generated from original LMPs and assemble into a highly conductive particle network (LMPNet). Finally, we demonstrated a multi-layered E-PCB, in which various electronic components were integrated with tough adhesion to form a highly stretchable health monitoring system. Since our synthesis of LMPNet is universal, we could synthesize LMPNet in various polymers, including hydrogel, self-healing elastomer and photoresist and add new functions to LMPNet.

Materials for Stretchable Electronics Compliant with Printed Circuit Board Fabrication

2012 ◽  
pp. 161-185
Author(s):  
Matthias Adler ◽  
Ruth Bieringer ◽  
Thomas Schauber ◽  
Jürgen Günther
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Stretchable Electronics ◽  
Printed Circuit

Reliability and Application Scenarios of Stretchable Electronics Realized Using Printed Circuit Board Technologies

2012 ◽  
pp. 207-233 ◽  
Author(s):  
Jan Vanfleteren ◽  
Frederick Bossuyt ◽  
Thomas Löher ◽  
Yung-Yu Hsu ◽  
Mario Gonzalez ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Stretchable Electronics ◽  
Printed Circuit

A Solder Joint Reliability Model for the Philips Lumileds LUXEON Rebel LED Carrier Using Physics of Failure Methodology

2013 ◽  
Vol 2013 (1) ◽  
pp. 000887-000892 ◽  
Author(s):  
Rudi Hechfellner ◽  
Michiel Kruger ◽  
Tewe Heemstra ◽  
Greg Caswell ◽  
Nathan Blattau ◽  
...  
Keyword(s):  
Solder Joint ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Light Emitting Diodes ◽  
Coefficient Of Thermal Expansion ◽  
Thermal Control ◽  
Circuit Board ◽  
System Level ◽  
Light Emitting ◽  
Printed Circuit

Light Emitting Diodes (LEDs) are quickly evolving as the dominant lighting solution for a wide variety of applications. With the elimination of incandescent light bulbs and the toxic limitations of fluorescent bulbs, there has been a dramatic increase in the interest in high-brightness light emitting diodes (HB-LEDs). Getting the light out of the die, with reliable color, while maintaining appropriate thermal control over a long service life is a challenge. These issues must be understood and achieved to meet the needs of unique applications, such as solidstate-lighting, automotive, signage, and medical applications. These applications have requirements for 15–25 years of operation making their reliability of critical importance. The LUXEON Rebel has been accepted as an industry leading LED product, widely used in Mean-Time-Between-Failure (MTBF) sensitive applications. Customers use various mounting platforms, such as FR4 Printed Circuit Board (PCB), FR4 PCB with thermal via's, Aluminum & Copper Metal Core printed Circuit Boards (MCPCB), Super MCPCB, etc. As in other LEDs, when mounting to a platform where a large Coefficient of Thermal Expansion (CTE) exists between the LED & the PCB, Solder fatigue could become an issue that may affect system level lifetime. In this paper we have examined extreme cases and how a solder joint can impact system level reliability. We have modeled the conditions and formed a means to predict system level reliability. We have compared the prediction modeling with empirical tests for validation of the models. It is vital to understand system level reliability factors to build lighting solutions that match the application and customer expectations. It is impractical to test LEDs and other components for 50k hours ~5 years since the device evolution is much faster than that – on average one LED generation every 12–18 month. Hence we need models and prediction methods …..

scholarly journals Thermal and Electrical Analysis of Solid Aluminium Capacitors

1987 ◽  
Vol 12 (3) ◽  
pp. 167-186 ◽  
Author(s):  
E. H.L.J. Dekker ◽  
C. J.M. Lasance
Keyword(s):  
Thermal Properties ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Electronic Components ◽  
Reverse Voltage ◽  
Printed Circuit ◽  
Electrolytic Capacitors ◽  
Extensive Analysis ◽  
Current Specification ◽  
Electrical Analysis

The thermal properties of electronic components partly determine the reliability of electronic equipment. For electrolytic capacitors, they also set the limits for the ripple current and voltage values.This article first discusses the voltage limits under various conditions of temperature, frequency and polarity. Then the connection of ripple current to these parameters and to the capacitor's resistance is treated.An extensive analysis is made of the influence of heat conduction in the capacitor and the printed-circuit board, for metal-cased as well as for epoxy-coated pearl types. The study pays particular attention to solid aluminium capacitors containing a manganese dioxide semiconductor. They have some extraordinary properties: a temperature range of at least – 80 to + 175℃, and an appreciable reverse voltage potential.These can be fully employed to improve the ripple-current specification.

Effects of Trace Layers and Joule Heating on the Temperature Distribution of Printed Circuit Boards: A Computational Study

2009 ◽  
Vol 1 (2) ◽  
Author(s):  
M. Baris Dogruoz ◽  
Manoj K. Nagulapally
Keyword(s):  
Joule Heating ◽  
Hot Spots ◽  
Printed Circuit Board ◽  
Computational Study ◽  
Computational Cost ◽  
Circuit Board ◽  
System Level ◽  
Printed Circuit ◽  
System Level Simulation ◽  
Background Mesh

A printed circuit board (PCB) is generally a multilayered board made of dielectric material and several layers of traces and vias. Performing detailed system-level computational fluid dynamics (CFD) simulations of PCBs including meshed trace and via geometries for each of the layers is impractical. In the present approach, the effects of the trace and via geometry are accurately modeled in the physical model by importing electronics computer aided-design data consisting of the trace and via layout of the board and computing locally varying orthotropic conductivity (kx, ky, and kz) on the printed circuit board using a background mesh. The spatially varying orthotropic conductivity is then mapped from the background mesh to the CFD mesh and used in a system-level simulation of the PCB with a minimal increase in the overall computational cost. On the other hand, as PCB component densities increase, the current densities increase thereby leading to regions of hot spots due to Joule heating. Hence, it is essential that the computational heat transfer simulations account for the heating due to the high current carrying traces. In order to accurately model the Joule heating of traces and vias, it is of essence to solve for the conservation of current in each of these traces. In this study, the effects of both trace layer nonhomogeneity and Joule heating are examined on a sample PCB with several components attached to it. The results are then compared with those from the conventional modeling techniques. It is demonstrated that there is considerable difference in the location of the hot spots and temperature values between two different methods.

SILVerIn: Systematic Integrity Verification of Printed Circuit Board Using JTAG Infrastructure

2021 ◽  
Vol 17 (3) ◽  
pp. 1-28
Author(s):  
Shubhra Deb Paul ◽  
Swarup Bhunia
Keyword(s):  
Integrated Circuit ◽  
Printed Circuit Board ◽  
Supply Voltage ◽  
Semiconductor Industry ◽  
Electronic System ◽  
Circuit Board ◽  
System Level ◽  
Printed Circuit ◽  
Industry Standard ◽  
Custom Hardware

A printed circuit board (PCB) provides necessary mechanical support to an electronic system and acts as a platform for connecting electronic components. Counterfeiting and in-field tampering of PCBs have become significant security concerns in the semiconductor industry as a result of increasing untrusted entities in the supply chain. These counterfeit components may result in performance degradation, profit reduction, and reputation risk for the manufacturers. While Integrated Circuit (IC) level authentication using physical unclonable functions (PUFs) has been widely investigated, countermeasures at the PCB level are scarce. These approaches either suffer from significant overhead issues, or opportunistic counterfeiters can breach them like clockwork. Besides, they cannot be extended to system-level (both chip and PCB together), and their applications are also limited to a specific purpose (i.e., either counterfeiting or tampering). In this article, we introduce SILVerIn , a novel systematic approach to verify the authenticity of all chips used in a PCB as well as the board for combating attacks such as counterfeiting, cloning, and in-field malicious modifications. We develop this approach by utilizing the existing boundary scan architecture (BSA) of modern ICs and PCBs. As a result, its implementation comes at a negligible (∼0.5%) hardware overhead. SILVerIn  is integrated into a PCB design during the manufacturing phase. We implement our technique on a custom hardware platform consisting of an FPGA and a microcontroller. We incorporate the industry-standard JTAG (Joint Test Action Group) interface to transmit test data into the BSA and perform hands-on measurement of supply current at both chip and PCB levels on 20 boards. We reconstruct these current values to digital signatures that exhibit high uniqueness, robustness, and randomness features. Our approach manifests strong reproducibility of signatures at different supply voltage levels, even with a low-resolution measurement setup. SILVerIn  also demonstrates a high resilience against machine learning-based modeling attacks, with an average prediction accuracy of ∼51%. Finally, we conduct intentional alteration experiments by replacing the on-board FPGA to replicate the scenario of PCB tampering, and the results indicate successful detection of in-field modifications in a PCB.

Realistic warpage evaluation of printed board assembly during reflow process

2015 ◽  
Vol 27 (4) ◽  
pp. 137-145 ◽  
Author(s):  
Soonwan Chung ◽  
Jae B. Kwak
Keyword(s):  
Numerical Simulation ◽  
Boundary Conditions ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Contact Boundary ◽  
Electronic Components ◽  
Reflow Process ◽  
Common Component ◽  
Content Type ◽  
Printed Circuit

Purpose – This paper aims to develop an estimation tool for warpage behavior of slim printed circuit board (PCB) array while soldering with electronic components by using finite element method. One of the essential requirements for handheld devices, such as smart phone, digital camera, and Note-PC, is the slim design to satisfy the customers’ desires. Accordingly, the printed circuit board (PCB) should be also thinner for a slim appearance, which would result in decreasing the PCB’s bending stiffness. This means that PCB deforms severely during the reflow (soldering) process where the peak temperature goes up to 250°C. Therefore, it is important to estimate PCB deformation at a high temperature for thermo-mechanical quality/reliability after reflow process. Design/methodology/approach – A numerical simulation technique was devised and customized to accurately estimate the behavior of a thin printed board assembly (PBA) during reflow by considering all components, including PCB, microelectronic packages and solder interconnects. Findings – By applying appropriate constraints and boundary conditions, it was found that PBA’s warpage can be accurately predicted during the reflow process. The results were also validated by warpage measurement, which showed a fairly good agreement with one and another. Research limitations/implications – For research limitations, there are many assumptions regarding numerical modeling. That is, the viscoplastic material property of solder ball is ignored, the reflow profile is simplified and the accurate heat capacity is not considered. Furthermore, the residual stress within the PCB, generated at PCB manufacturing process, is not included in this paper. Practical implications – This paper shows how to calculate PBA warpage during the reflow process as accurately as possible. This methodology helps a PCB designer and surface-mount technology (SMT) process manager to predict a PBA warpage issue and modify PCB design before PCB real fabrication. Practically, this modeling and simulation process can be easily performed by using a graphical user interface (GUI) module, so that the engineer can handle an issue by inputting some numbers and clicking some buttons. Social implications – In a common sense manner, a numerical simulation method can decrease time and cost in manufacturing real samples. This PCB warpage method can also decrease product development duration and produce a new product earlier. Furthermore, PCB is a common component in all the electronic devices. So, this PCB warpage method can have various applications. Originality/value – Because of an economic advantage, the development of a numerical simulation tool for estimating the thin PBA warpage behaviour during reflow process was attempted. The developed tool contains the features of detailed modeling for electronic components and contact boundary conditions of the supporting rails in the reflow oven.

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