Influence of the area of a thermal pad on optical and thermal parameters of LED modules

Circuit World ◽  
2020 ◽  
Vol 46 (2) ◽  
pp. 65-70 ◽  
Author(s):  
Krzysztof Górecki ◽  
Przemysław Piotr Ptak
Keyword(s):  
Thermal Resistance ◽  
Power Density ◽  
Printed Circuit Board ◽  
Thermal Parameters ◽  
Circuit Board ◽  
Optical Parameters ◽  
Metal Core ◽  
Content Type ◽  
Printed Circuit

Purpose The purpose of this paper is to present and discuss the results of measurements illustrating influence of the area of a thermal pad and the kind of the used base on thermal and optical parameters of LED modules. Design/methodology/approach LED modules including six power LEDs are designed. In the layout of these modules, different areas of a thermal pad of each LED are used. These modules are made using the classical FR-4 base and metal core printed circuit board (MCPCB). Thermal and optical parameters of all the tested modules are measured using the method elaborated by the authors. Findings The obtained results of measurements prove that increasing the area of a thermal pad causes a decrease in thermal resistance of the tested LED modules and an increase in power density of the emitted light. The role of the area of a thermal pad is more important for the classical FR-4 base than for MCPCB. Research limitations/implications Investigations were performed for only two values of the area of thermal pads and selected values of LEDs forward current. Originality/value The presented results of investigations show how the used layout and type of the used base of these modules influence optical and thermal parameters of LED modules. Changing the base of a module can cause even a double decrease in thermal resistance and a double increase in power density of the emitted light.

Influence of the soldering paste type on optical and thermal parameters of LED modules

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Krzysztof Górecki ◽  
Przemysław Ptak ◽  
Barbara Dziurdzia
Keyword(s):  
Design Methodology ◽  
Printed Circuit Board ◽  
Electrical Energy ◽  
Thermal Parameters ◽  
Circuit Board ◽  
Metal Core ◽  
Content Type ◽  
Printed Circuit ◽  
Soldering Process ◽  
Practical Implications

Purpose This paper presents the results of the investigations of LED modules soldered with the use of different soldering pastes. Design/methodology/approach The tested power LED modules are soldered using different solder pastes and soldering processes. Thermal parameters of the performed modules are tested using indirect electrical methods. The results of measurements obtained for different modules are compared and discussed. Findings It was shown that the soldering process visibly influences the results of measurements of optical and thermal parameters of LED modules. For example, values of thermal resistance of these modules and the efficiency of conversion of electrical energy into light differ between each other even by 15%. Practical implications The obtained results of investigations can be usable for designers of the assembly process of power LED modules. Originality/value This paper shows the investigations results in the area of effective assembly of power LEDs to the metal core printed circuit board (MCPCB) using different soldering pastes (REL22, REL61, LMPA-Q6, OM-5100, OM-338-PT, M8, OM-340, CVP-390). It was shown that the best thermal and optical properties of these modules are obtained for the OM5100 paste by Alpha Assembly.

The influence of soldering process parameters on the optical and thermal properties of power LEDs

2020 ◽  
Vol 32 (4) ◽  
pp. 191-199
Author(s):  
Przemysław Ptak ◽  
Krzysztof Górecki ◽  
Agata Skwarek ◽  
Krzysztof Witek ◽  
Jacek Tarasiuk
Keyword(s):  
Thermal Resistance ◽  
Process Parameters ◽  
Printed Circuit Board ◽  
Luminous Flux ◽  
Circuit Board ◽  
Optical Parameters ◽  
Light Sources ◽  
Content Type ◽  
Soldering Process ◽  
Design Engineers

Purpose This paper aims to present the results of investigations that show the influence of soldering process parameters on the optical and thermal parameters of power LEDs. Design/methodology/approach The power LEDs were soldered onto metal core printed circuit board (MCPCB) substrates in different soldering ovens: batch and tunnel types, characterized by different thermal profiles. Three types of solder pastes based on Sn99Ag0.3Cu0.7 with the addition of TiO2 were used. The thermal and optical parameters of the diodes were measured using classical indirect electrical methods. The results of measurements obtained were compared and discussed. Findings It was shown that the type of oven and soldering thermal profile considerably influence the effectiveness of the removal of heat generated in the LEDs tested. This influence is characterized by thermal resistance changes. The differences between the values of this parameter can exceed 20%. This value also depends on the composition of the soldering paste. The differences between the diodes tested can exceed 15%. It was also shown that the luminous flux emitted by the diode depends on the soldering process used. Practical implications The results obtained could be useful for process design engineers for assembling power LEDs for MCPCBs and for designers of solid-state light sources. Originality/value This paper presents the results of investigations into the influence of the soldering profiles and soldering pastes used on the effectiveness of the removal of heat generated in power LEDs. It shows and discusses how the factors mentioned above influence the thermal resistance of the LEDs and optical parameters that characterize the light emitted.

Evaluation of new technologies and materials for printed circuit boards with improved heat dissipation properties

Circuit World ◽  
2016 ◽  
Vol 42 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Michal Baszynski ◽  
Edward Ramotowski ◽  
Dariusz Ostaszewski ◽  
Tomasz Klej ◽  
Mariusz Wojcik ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Printed Circuit Boards ◽  
Heat Dissipation ◽  
Printed Circuit Board ◽  
New Technologies ◽  
Electronic Device ◽  
Circuit Board ◽  
New Materials ◽  
Content Type ◽  
Printed Circuit

Purpose – The purpose of this paper is to evaluate thermal properties of printed circuit board (PCB) made with use of new materials and technologies. Design/methodology/approach – Four PCBs with the same layout but made with use of different materials and technologies have been investigated using thermal camera to compare their thermal properties. Findings – The results show how important the thermal properties of PCBs are for providing effective heat dissipation, and how a simple alteration to the design can help to improve the thermal performance of electronic device. Proper layout, new materials and technologies of PCB manufacturing can significantly reduce the temperature of electronic components resulting in higher reliability of electronic and power electronic devices. Originality/value – This paper shows the advantages of new technologies and materials in PCB thermal management.

Thermal Model of Printed Circuit Board Plated-Through Hole under One-Sided Heating Conditions

2021 ◽  
Vol 26 (5) ◽  
pp. 426-431
Author(s):  
V.A. Sergeev ◽  
◽  
A.M. Khodakov ◽  
M.Yu. Salnikov ◽  
◽  
...  
Keyword(s):  
Quality Control ◽  
Thermal Resistance ◽  
Thermal Model ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Thermal Models ◽  
Printed Circuit ◽  
Plated Through Hole ◽  
Through Hole

Thermal methods of quality control of the plated-through hole (PTH) of printed circuit board (PCB) are based on thermal models. However, known thermal models of PTH take no account of heat transfer to PCB material thus not allowing for PTH heat characteristic tying up with adhesion quality. In this work, an axisymmetric thermal model of a single-layer PCB PTH under one-sided heating conditions is considered. It was shown that the ratio of the temperature increments of the upper (heated) and lower end of the PTH in the considered range of heating power does not depend on the power level. A linear thermal equivalent scheme of the PTH has been proposed, which includes the longitudinal thermal resistance of the PTH metallization, de-termined by the parameters and quality of the metallization layer, the thermal resistance, which determines the convection heat exchange between the ends of the PTH with the adjacent PCB surface and the environment, and the thermal resistance of the area of the PCB material adjacent to the PTH, depending on the quality of the metallization adhesion and the PCB dielectric. Thermal equivalent circuit parameters determined by the ratio of the temperature increment of the upper and lower ends of the PTH and their difference can serve as the basis for the development of a nondestructive inspection procedure for PTH quality control by way of its unilateral heating, for example, by a laser beam.

Robotic system design and development for automated dismantling of PCB waste

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ioan Doroftei ◽  
Daniel Chirita ◽  
Ciprian Stamate ◽  
Stelian Cazan ◽  
Carlos Pascal ◽  
...  
Keyword(s):  
Design Methodology ◽  
Printed Circuit Board ◽  
Vision System ◽  
Electronic Waste ◽  
Robotic System ◽  
Circuit Board ◽  
Short Introduction ◽  
Content Type ◽  
Printed Circuit ◽  
System A

Purpose The mass electronics sector is one of the most critical sources of waste, in terms of volume and content with dangerous effects on the environment. The purpose of this study is to provide an automated and accurate dismantling system that can improve the outcome of recycling. Design/methodology/approach Following a short introduction, the paper details the implementation layout and highlights the advantages of using a custom architecture for the automated dismantling of printed circuit board waste. Findings Currently, the amount of electronic waste is impressive while manual dismantling is a very common and non-efficient approach. Designing an automatic procedure that can be replicated, is one of the tasks for efficient electronic waste recovery. This paper proposes an automated dismantling system for the advanced recovery of particular waste materials from computer and telecommunications equipment. The automated dismantling architecture is built using a robotic system, a custom device and an eye-to-hand configuration for a stereo vision system. Originality/value The proposed approach is innovative because of its custom device design. The custom device is built using a programmable screwdriver combined with an innovative rotary dismantling tool. The dismantling torque can be tuned empirically.

Analysis of surface insulation resistance related failures in electronics by circuit simulation

Circuit World ◽  
2017 ◽  
Vol 43 (2) ◽  
pp. 45-55 ◽  
Author(s):  
Vadimas Verdingovas ◽  
Salil Joshy ◽  
Morten Stendahl Jellesen ◽  
Rajan Ambat
Keyword(s):  
Printed Circuit Board ◽  
Electronic Device ◽  
Early Stage ◽  
Circuit Simulation ◽  
Circuit Board ◽  
Insulation Resistance ◽  
Electronic Circuits ◽  
Content Type ◽  
Printed Circuit ◽  
Surface Insulation Resistance

Purpose The purpose of this study is to show that the humidity levels for surface insulation resistance (SIR)-related failures are dependent on the type of activators used in no-clean flux systems and to demonstrate the possibility of simulating the effects of humidity and contamination on printed circuit board components and sensitive parts if typical SIR data connected to a particular climatic condition are available. This is shown on representative components and typical circuits. Design/methodology/approach A range of SIR values obtained on SIR patterns with 1,476 squares was used as input data for the circuit analysis. The SIR data were compared to the surface resistance values observable on a real device printed circuit board assembly. SIR issues at the component and circuit levels were analysed on the basis of parasitic circuit effects owing to the formation of a water layer as an electrical conduction medium. Findings This paper provides a summary of the effects of contamination with various weak organic acids representing the active components in no-clean solder flux residue, and demonstrates the effect of humidity and contamination on the possible malfunctions and errors in electronic circuits. The effect of contamination and humidity is expressed as drift from the nominal resistance values of the resistors, self-discharge of the capacitors and the errors in the circuits due to parasitic leakage currents (reduction of SIR). Practical/implications The methodology of the analysis of the circuits using a range of empirical leakage resistance values combined with the knowledge of the humidity and contamination profile of the electronics can be used for the robust design of a device, which is also important for electronic products relying on low current consumption for long battery lifetime. Originality/value Examples provide a basic link between the combined effect of humidity and contamination and the performance of electronic circuits. The methodology shown provides the possibility of addressing the climatic reliability of an electronic device at the early stage of device design by using typical SIR data representing the possible climate exposure.

Superconducting Multilayer High-Density Flexible Printed Circuit Board for Very High Thermal Resistance Interconnections

2018 ◽  
Vol 193 (3-4) ◽  
pp. 578-584 ◽  
Author(s):  
Xavier de la Broïse ◽  
Alain Le Coguie ◽  
Jean-Luc Sauvageot ◽  
Claude Pigot ◽  
Xavier Coppolani ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Printed Circuit Board ◽  
High Density ◽  
Circuit Board ◽  
Printed Circuit ◽  
Flexible Printed Circuit ◽  
High Thermal Resistance ◽  
Very High

Study on fine lines and undercut suppression of printed circuit board prepared by electrolytic etching

Circuit World ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Denglin Fu ◽  
Yanan Wen ◽  
Jida Chen ◽  
Lansi Lu ◽  
Ting Yan ◽  
...  
Keyword(s):  
Corrosion Inhibitor ◽  
Corrosion Inhibitors ◽  
Printed Circuit Board ◽  
Copper Surface ◽  
Etching Process ◽  
Circuit Board ◽  
Content Type ◽  
Printed Circuit ◽  
Etching Method ◽  
Electrolytic Etching

Purpose The purpose of this paper is to study an electrolytic etching method to prepare fine lines on printed circuit board (PCB). And the influence of organics on the side corrosion protection of PCB fine lines during electrolytic etching is studied in detail. Design/methodology/approach In this paper, the etching factor of PCB fine lines produced by new method and the traditional method was analyzed by the metallographic microscope. In addition, field emission scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to study the inhibition of undercut of the four organometallic corrosion inhibitors with 2,5-dimercapto-1,3,4-thiadiazole, benzotriazole, l-phenylalanine and l-tryptophan in the electrolytic etching process. Findings The SEM results show that corrosion inhibitors can greatly inhibit undercut of PCB fine lines during electrolytic etching process. XPS results indicate that N and S atoms on corrosion inhibitors can form covalent bonds with copper during electrolytic etching process, which can be adsorbed on sidewall of PCB fine lines to form a dense protective film, thereby inhibiting undercut of PCB fine lines. Quantum chemical calculations show that four corrosion inhibitor molecules tend to be parallel to copper surface and adsorb on copper surface in an optimal form. COMSOL Multiphysics simulation revealed that there is a significant difference in the amount of corrosion inhibitor adsorbed on sidewall of the fine line and the etching area. Originality/value As a clean production technology, electrolytic etching method has a good development indicator for the production of high-quality fine lines in PCB industry in the future. And it is of great significance in saving resources and reducing environmental pollution.

Surface temperature of electronic assemblies equipped with tilted and low-powered QFN64 subjected to free convection

2017 ◽  
Vol 27 (6) ◽  
pp. 1304-1310 ◽  
Author(s):  
Abderrahmane Baïri ◽  
Clara Ortega Hermoso ◽  
David San Martén Ortega ◽  
Iken Baïri ◽  
Zsolt Peter
Keyword(s):  
Surface Temperature ◽  
Inclination Angle ◽  
Printed Circuit Board ◽  
Electronic Device ◽  
Thermal Design ◽  
Circuit Board ◽  
Content Type ◽  
Printed Circuit ◽  
Volume Method ◽  
Electronic Assemblies

Purpose This work deals with the case of the quad flat non-lead 64 (QFN64) electronic package generating a low power range ranging from 0.01 to 0.1W. It is installed on one side of a printed circuit board (PCB) that can be inclined relative to the horizontal plane with an angle varying between 0° and 90° (horizontal and vertical positions, respectively). The surface temperature of the electronic assembly is subjected to air natural convection. Design/methodology/approach Calculations are done by means of the finite volume method for many configurations obtained by varying the generated power and the inclination angle. Findings The distribution of the surface temperature is determined on all the assembly areas (QFN and PCB). The study shows that the thermal behaviour of the electronic device is influenced by the generated power and the inclination angle. The 3D numerical survey leads to correlations allowing calculation of the average surface temperature in any part of the assembly, according to the power generated by the QFN64 and the inclination angle. Originality/value The proposed accurate correlations are original and unpublished. They optimize the thermal design of the electronic QFN64 package, which is increasingly used in many engineering fields.

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