In-situ Solder Joint Crack Detection via Signal Reflection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Detecting cracks in solder joints on printed circuit boards (PCBs) in information handling systems is challenging due to mechanical stresses, which can lead to electrical failures and reduced signal integrity, especially in high-speed data communication interfaces, and existing methods are difficult to determine the root cause of failures.
Innovation Solution
A system comprising a device with first and second contacts soldered to the PCB, a signal generator sending a test signal through the solder joints, and a detector using a termination resistor and ground plane to monitor reflected signals for impedance discontinuities, indicating crack presence, with report logic interpreting signal magnitudes to provide crack warnings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional inspection methods are used to detect solder joint cracks, then the system can identify obvious failures, but the detection precision is insufficient for early-stage or subtle cracks
Solution Approach 1:
The patent replaces mechanical inspection methods with an electrical signal-based detection system. A test signal is applied to the solder joint, and impedance changes caused by cracks are measured electrically, enabling precise detection without complex mechanical probing or visual inspection equipment.
Solution Approach 2:
The patent introduces a test signal as an intermediary to detect crack conditions. The signal travels through the solder joint, and its reflection or impedance change serves as a mediator that reveals the presence of cracks without directly interacting with the physical structure in a complex manner.
2Reliability
If the detection system monitors all solder joints continuously, then the reliability of the system improves, but the energy consumption and device complexity increase
Solution Approach 1:
The detection system operates periodically rather than continuously, applying test signals at intervals to monitor solder joint integrity. This periodic operation maintains system reliability by detecting cracks when they occur while significantly reducing energy consumption compared to continuous monitoring.
Solution Approach 2:
The system applies a test signal only when needed for detection rather than maintaining constant monitoring. This partial action approach provides sufficient reliability for crack detection while minimizing energy usage by activating the detection function only when a test is required.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively detects cracks in solder joints, enabling early identification of potential failures, reducing system errors, and allowing for proactive maintenance by differentiating between no cracking, moderate, and significant crack conditions.
Implementation Method 1
The detector may receive a reflected signal that is a reflection of the test signal from at least one of the first solder joint, the second solder joint, and the termination resistor
Implementation Method 2
A system may detect cracks in solder joints on a printed circuit board (PCB)... based upon a magnitude of the reflected signal
Data Source
AI summary
A system detects cracks in solder joints on a printed circuit board (PCB). The system includes a device, a signal generator, a termination resistor, and a detector. The device includes a first contact and a second contact coupled to the first contact. The device is soldered to the PCB by a first solder joint at the first contact and by a second solder joint at the second contact. The signal generator has a test signal output coupled to the first solder joint. The termination resistor has a first terminal coupled to the second solder joint, and a second terminal coupled to a ground plane of the PCB. The detector receives a reflected signal that is a reflection of the test signal from at least one of the first solder joint, the second solder joint, and the termination resistor. The detector provides an indication as to whether or not at least one of the first solder joint and the second solder joint is cracked based upon a magnitude of the reflected signal.