Effect of Voiding in Solder Joints on Thermal Performance of the LED

2013 ◽  
Vol 2013 (1) ◽  
pp. 000895-000901
Author(s):  
Jianbiao Pan
Keyword(s):  
Thermal Performance ◽  
Printed Circuit Board ◽  
Solder Joints ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Circuit Board ◽  
Junction Temperature ◽  
Solder Paste ◽  
Led Lighting ◽  
Operational Life

Light-Emitting Diode (LED) lighting has potential to fundamentally alter lighting by replacing incandescent and fluorescent technologies because it offers significant energy saving, longer operational life, and many other advantages. Excellent thermal management and low-cost is vital for LED lighting to become the market standard for general lighting. The packaged LED is typically soldered to the metal-core printed circuit board (MCPCB). However, as the size of the packaged LED increases, voiding in solder joints becomes a major problem since voiding increases the thermal resistance. The research questions are: what is the effect of flux in solder paste and the LED size on the voiding? What is the relationship between the voiding and the thermal performance of the LED? In this study, packaged LEDs with three different sizes were assembled to MCPCBs using solder paste with two different types of fluxes. The voiding in solder joints was imaged by an X-Ray machine. The detailed void characteristics were analyzed. The LED's junction temperature was measured based on the diode's forward voltage junction temperature measurement method. The results show that both flux in solder paste and the LED size have significant effect on the voiding. There is weak positive correlation between the voiding and the thermal performance when the voiding is over 25% coverage. However, the effect of voiding on the thermal performance is insignificance when the voiding is less than 25% coverage.

Low-cost thin-film passive RFID circuits and detector system

2020 ◽  
Vol 12 (5) ◽  
pp. 356-366
Author(s):  
Salma El-Sawy ◽  
Wasim Nawaz ◽  
Mohamed Osama ◽  
Ahmet Tekin
Keyword(s):  
Printed Circuit Board ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Flexible Substrate ◽  
Circuit Board ◽  
Detection Methods ◽  
Single Chip ◽  
Analog To Digital ◽  
Inductively Coupled ◽  
Passive Rfid

AbstractThis paper discusses the design of chip-less RFID tags of a standard pocket size of 69 mm by 156 mm. These tags are based on lumped elements of copper metal traces constructed on a thin polyamide flexible substrate. Moreover, a low-cost single-chip Bluetooth detector circuit system is demonstrated. Two different detection methods: variable coil load coupling and optical light intensity detection were combined to yield 256 unique ID codes. In the first method, by utilizing simple 4 MHz digital drivers and an integrated analog to digital converter (ADC) in the reader controller; various inductively coupled resonant loads corresponding to multiple distinct tags could be differentiated, yielding eight different (3-bit) ID codes. The additional via-based hole pattern reflectometer method creates additional 32 distinct levels (5-bit) utilizing 650 nm visible light-emitting diode and a simple trans-impedance operational along with the same analog ADC pins of a Bluetooth controller. The printed circuit board trace coil on the two-layer low-cost FR-4 waterproof sealed detector unit is simultaneously used as a Qi wireless power receiver to charge the120 mAh 2450 Lithium Polymer (LiR) battery. The device could remain operational for more than a month with a single charge; remaining connected with a mobile device and enabling 10 readouts daily.

scholarly journals Design and Implementation of Solder Paste Dispenser Based on Linear Drive System

2019 ◽  
Vol 3 (2) ◽  
pp. 338
Author(s):  
Riky Tri Yunardi ◽  
Moh. Zakky Zulfiar ◽  
Rr. Wanda Auruma Putri ◽  
Deny Arifianto
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Low Cost ◽  
Circuit Board ◽  
Solder Paste ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Design And Implementation ◽  
Stepper Motors ◽  
Drive Systems

In the technology to create prototypes for electronic hardware is usually constructed using surface mount device printed circuit board (SMD PCB). In this paper introduces the design and implementation of low-cost electrical solder paste dispenser that supports the PCB solder process. The design consists of a nozzle and linear drive systems based on stepper motors operating with electric power to push the plunger down to drop the solder paste on the board. To test the performance of solder paste that has been designed verified by experiment. Solder paste dispenser design was tested using SMD resistor with the solder pads of different sizes for R0603, R0805, and R1206 on PCB. The results showed that the design of the prototype was able to put the pasta in various field pads between 0.54 mm2, 0.91 mm2 and 1.44 mm2 for standard solder pads with an error in the 2% - 5%. Based on the results, the device has been shown to potentially be used to attach electronic components to printed circuit boards.

scholarly journals The Effect of Epoxy Polymer Addition in Sn-Ag-Cu and Sn-Bi Solder Joints

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 960 ◽  
Author(s):  
Min-Soo Kang ◽  
Do-Seok Kim ◽  
Young-Eui Shin
Keyword(s):  
Solder Joint ◽  
Strain Energy ◽  
Printed Circuit Board ◽  
Solder Joints ◽  
Circuit Board ◽  
Solder Paste ◽  
Element Analysis ◽  
Printed Circuit ◽  
Shock Testing ◽  
Polymer Addition

To analyze the reinforcement effect of adding polymer to solder paste, epoxies were mixed with two currently available Sn-3.0Ag-0.5Cu (wt.% SAC305) and Sn-59Bi (wt.%) solder pastes and specimens prepared by bonding chip resistors to a printed circuit board. The effect of repetitive thermal stress on the solder joints was then analyzed experimentally using thermal shock testing (−40 °C to 125 °C) over 2000 cycles. The viscoplastic stress–strain curves generated in the solder were simulated using finite element analysis, and the hysteresis loop was calculated. The growth and propagation of cracks in the solder were also predicted using strain energy formulas. It was confirmed that the epoxy paste dispersed the stress inside the solder joint by externally supporting the solder fillet, and crack formation was suppressed, improving the lifetime of the solder joint.

The dependence of reliability and mechanical strength of the solder joints in 3D PoP structures from sizes of solder powders applied in soldering materials

2017 ◽  
Vol 29 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Janusz Sitek ◽  
Marek Koscielski ◽  
Janusz Borecki ◽  
Tomasz Serzysko
Keyword(s):  
Mechanical Strength ◽  
Printed Circuit Board ◽  
Solder Joints ◽  
Positive Impact ◽  
Three Dimensional ◽  
Bottom Layer ◽  
Circuit Board ◽  
Solder Paste ◽  
Content Type ◽  
Materials Used

Purpose The purpose of this paper is to evaluate the influence of solder powders sizes applied in soldering materials used for Package-on-Package (PoP) system manufacture as well as other factors on reliability and mechanical strength of created solder joints in three-dimensional (3D) PoP structures. Design/methodology/approach The design of experiments based on the Genichi Taguchi method were used in the investigation. The main factors covered different printed circuit board (PCB) coatings, soldering materials with solder powders sizes from Types 3 to 7 and soldering profiles. The reliability of 3D PoP structures was determined by measurements of resistance of daisy-chain solder joints systems during thermal shocks (TS) cycles. The mechanical strength of solder joints in 3D PoP structures was determined by measurements of a shear force of “Top” layer of 3D structures at T0 and after 1,500 TS. The ANOVA was used for results assessment. Findings The size of solder powders applied in soldering materials had small (10 per cent) influence on mechanical strength of solder joints in 3D PoP structures. Small size of solder powder had positive effect on solder joints reliability in 3D PoP structures. Especially important was the selection of solder paste for “Bottom” layer of 3D PoP system (influence 17 per cent). Incorrect soldering profile (influence 46 per cent) or wrong selected PCB coating (influence 35 per cent) can very easily reduce the positive impact of soldering materials on solder joints reliability. It was stated that as low as possible soldering profile and organic solderability preservative (OSP) coating in the case of single-sided PCB are the best for 3D PoP structures due to their reliability. Originality/value This paper explains how different sizes of solder powders used nowadays in solder pastes influence on reliability and mechanical strength of the solder joints in 3D PoP structures. The contribution, in numerical values, of soldering materials, soldering profile and PCB coating on 3D PoP structures solder joints reliability as well as recommendations improving reliability of 3D PoP structures solder joints were presented.

Temperature and Humidity Dependent Reliability Analysis of RGB LED Chips

2006 ◽  
Author(s):  
Jun-Xian Fu ◽  
Shukri Souri ◽  
James S. Harris
Keyword(s):  
Reliability Analysis ◽  
Printed Circuit Board ◽  
Light Emitting Diode ◽  
Circuit Board ◽  
Light Emitting ◽  
Printed Circuit ◽  
Root Cause ◽  
Micro Cracks ◽  
Temperature And Humidity

Abstract Temperature and humidity dependent reliability analysis was performed based on a case study involving an indicator printed-circuit board with surface-mounted multiple-die red, green and blue light-emitting diode chips. Reported intermittent failures were investigated and the root cause was attributed to a non-optimized reflow process that resulted in micro-cracks and delaminations within the molding resin of the chips.

A Novel Wideband transition from Substrate Integrated Waveguide to Rectangular Waveguide

2020 ◽  
Vol 10 ◽  
Author(s):  
Keyur Mahant ◽  
Hiren Mewada ◽  
Amit Patel ◽  
Alpesh Vala ◽  
Jitendra Chaudhari
Keyword(s):  
Rectangular Waveguide ◽  
Printed Circuit Board ◽  
Low Cost ◽  
Single Layer ◽  
Circuit Board ◽  
Substrate Integrated Waveguide ◽  
Ka Band ◽  
Better Than ◽  
Millimeter Wave Circuits ◽  
Wideband Transition

Aim: In this article, wideband substrate integrated waveguide (SIW) and rectangular waveguide (RWG) transition operating in Ka-band is proposed Objective: In this article, wideband substrate integrated waveguide (SIW) and rectangular waveguide (RWG) transition operating in Ka-band is proposed. Method: Coupling patch etched on the SIW cavity to couple the electromagnetic energy from SIW to RWG. Moreover, metasurface is introduced into the radiating patch to enhance bandwidth. To verify the functionality of the proposed structure back to back transition is designed and fabricated on a single layer substrate using standard printed circuit board (PCB) fabrication technology. Results: Measured results matches with the simulation results, measured insertion loss is less than 1.2 dB and return loss is better than 3 dB for the frequency range of 28.8 to 36.3 GHz. By fabricating transition with 35 SRRs bandwidth of the proposed transition can be improved. Conclusion: The proposed transition has advantages like compact in size, easy to fabricate, low cost and wide bandwidth. Proposed structure is a good candidate for millimeter wave circuits and systems.

scholarly journals Compact Modelling of Electrical, Optical and Thermal Properties of Multi-Colour Power LEDs Operating on a Common PCB

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1286
Author(s):  
Krzysztof Górecki ◽  
Przemysław Ptak
Keyword(s):  
Integrated Circuits ◽  
Optical Model ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Junction Temperature ◽  
Optical Parameters ◽  
Spice Simulation ◽  
Light Emitting ◽  
Proposed Model ◽  
Good Agreement

This paper concerns the problem of modelling electrical, thermal and optical properties of multi-colour power light-emitting diodes (LEDs) situated on a common PCB (Printed Circuit Board). A new form of electro-thermo-optical model of such power LEDs is proposed in the form of a subcircuit for SPICE (Simulation Program with Integrated Circuits Emphasis). With the use of this model, the currents and voltages of the considered devices, their junction temperature and selected radiometric parameters can be calculated, taking into account self-heating phenomena in each LED and mutual thermal couplings between each pair of the considered devices. The form of the formulated model is described, and a manner of parameter estimation is also proposed. The correctness and usefulness of the proposed model are verified experimentally for six power LEDs emitting light of different colours and mounted on an experimental PCB prepared by the producer of the investigated devices. Verification was performed for the investigated diodes operating alone and together. Good agreement between the results of measurements and computations was obtained. It was also proved that the main thermal and optical parameters of the investigated LEDs depend on a dominant wavelength of the emitted light.

scholarly journals Highly Compact Through-Wire Microstrip to Empty Substrate Integrated Coaxial Line Transition

2021 ◽  
Vol 11 (15) ◽  
pp. 6885
Author(s):  
Marcos D. Fernandez ◽  
José A. Ballesteros ◽  
Angel Belenguer
Keyword(s):  
Printed Circuit Board ◽  
Low Cost ◽  
Coaxial Line ◽  
Circuit Board ◽  
Central Layer ◽  
Printed Circuit ◽  
Integrated Technology ◽  
Low Profile ◽  
The Many ◽  
High Degree

Empty substrate integrated coaxial line (ESICL) technology preserves the many advantages of the substrate integrated technology waveguides, such as low cost, low profile, or integration in a printed circuit board (PCB); in addition, ESICL is non-dispersive and has low radiation. To date, only two transitions have been proposed in the literature that connect the ESICL to classical planar lines such as grounded coplanar and microstrip. In both transitions, the feeding planar lines and the ESICL are built in the same substrate layer and they are based on transformed structures in the planar line, which must be in the central layer of the ESICL. These transitions also combine a lot of metallized and non-metallized parts, which increases the complexity of the manufacturing process. In this work, a new through-wire microstrip-to-ESICL transition is proposed. The feeding lines and the ESICL are implemented in different layers, so that the height of the ESICL can be independently chosen. In addition, it is a highly compact transition that does not require a transformer and can be freely rotated in its plane. This simplicity provides a high degree of versatility in the design phase, where there are only four variables that control the performance of the transition.

Validation of the Critical Strain-Based Methodology for Evaluating the Mechanical Safety of Ball Grid Array Solder Joints in a Launch Random Vibration Environment

2021 ◽  
Author(s):  
Tae-Yong Park ◽  
Hyun-Ung Oh
Keyword(s):  
Fatigue Life ◽  
Random Vibration ◽  
Critical Strain ◽  
Printed Circuit Board ◽  
Solder Joints ◽  
Mechanical Design ◽  
Ball Grid Array ◽  
Primary Objective ◽  
Circuit Board ◽  
Analytical Approaches

Abstract To overcome the theoretical limitations of Steinberg's theory for evaluating the mechanical safety of the solder joints of spaceborne electronics in a launch random vibration environment, a critical strain-based methodology was proposed and validated in a previous study. However, for the critical strain-based methodology to be used reliably in the mechanical design of spaceborne electronics, its effectiveness must be validated under various conditions of the package mounting locations and the first eigenfrequencies of a printed circuit board (PCB); achieving this validation is the primary objective of this study. For the experimental validation, PCB specimens with ball grid array packages mounted on various board locations were fabricated and exposed to a random vibration environment to assess the fatigue life of the solder joint. The effectiveness of the critical strain-based methodology was validated through a comparison of the fatigue life of the tested packages and their margin of safety, which was estimated using various analytical approaches.

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