Contactless Magnetic Field Sensor for Inaccessible Circuit Testing
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Solution Overview
Problem
Existing methods for testing electrical connections in electronic devices, such as integrated circuits and printed circuit board assemblies, face limitations due to inaccessible regions and the need for physical contact, which can cause damage and is impractical for high-density components like multilayer PCBs and advanced IC packages.
Innovation Solution
A contactless fault detection system using a surface coil with concentric loops to generate a magnetic field equivalent to a coaxial intermediate current loop, allowing for non-destructive testing by detecting variations in the magnetic field at a remote location, enabling identification of short and open circuits without physical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact probes are used to test electrical connections, then testing reliability is improved, but device damage risk increases and accessibility requirements worsen
Solution Approach 1:
The patent replaces the mechanical contact probe system with an electromagnetic field-based sensing system. A coil generates a magnetic field that induces current in the electrical connection under test, and a sensor detects the resulting magnetic field changes. This substitution eliminates physical contact, thereby removing the risk of contact-induced damage while maintaining testing capability through non-contact electromagnetic interaction.
Solution Approach 2:
The patent introduces an electromagnetic field as an intermediary between the testing system and the electrical connection. Instead of direct mechanical contact, the system uses a coil to generate a magnetic field that couples with the electrical connection, inducing test current through electromagnetic induction. The sensor then detects the response field, completing the non-contact measurement chain with the electromagnetic field serving as the mediating agent.
2Ease of operation
If contact probes are used for testing, then electrical connection testing is enabled, but accessibility requirements worsen due to inaccessible regions
Solution Approach 1:
The patent transitions from one-dimensional mechanical contact (requiring physical access to the test point) to three-dimensional electromagnetic field interaction. The magnetic field generated by the coil can penetrate through dielectric layers and reach electrical connections from a distance, enabling testing of components in multilayer PCBs and BGAs that are physically inaccessible to contact probes. This dimensional transition allows the testing system to access regions through space rather than requiring direct physical contact.
3Adaptability or versatility
If component density increases, then device functionality is improved, but testing capability worsens due to limited space for test points
Solution Approach 1:
The patent replaces the mechanical contact probe system with an electromagnetic field-based sensing system. A coil generates a magnetic field that induces current in the electrical connection under test, and a sensor detects the resulting magnetic field changes. This substitution eliminates physical contact, thereby removing the risk of contact-induced damage while maintaining testing capability through non-contact electromagnetic interaction.
Solution Approach 2:
The patent transitions from one-dimensional mechanical contact (requiring physical access to the test point) to three-dimensional electromagnetic field interaction. The magnetic field generated by the coil can penetrate through dielectric layers and reach electrical connections from a distance, enabling testing of components in multilayer PCBs and BGAs that are physically inaccessible to contact probes. This dimensional transition allows the testing system to access regions through space rather than requiring direct physical contact.
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
Enables safe and non-destructive testing of electrical connections in inaccessible regions, avoiding damage to faulty devices and overcoming the limitations of traditional contact-based methods, particularly in high-density components like multilayer circuit boards and advanced IC packages.
Implementation Method 1
a surface coil comprising a plurality of concentric loops disposed at a first region located away from the electrical connections. The concentric loops generate a first magnetic field passing through the electrical connections... based on an excitation current in the surface coil
Implementation Method 2
a sensor adapted to detect a second magnetic field at a second region located away from the electrical connections, wherein variations in the detected second magnetic field provide categories of performance of the electrical connections
Data Source
AI summary
A sensor device for testing electrical connections using contactless fault detection is disclosed. The sensor device includes: a surface coil comprising a plurality of concentric loops disposed at a first region located away from the electrical connections. The concentric loops generate a first magnetic field passing through the electrical connections, and the first magnetic field is equivalent to that generated by a coaxial intermediate current loop adjacent to the electrical connections based on an excitation current in the surface coil. The sensor device further includes a sensor adapted to detect a second magnetic field at a second region located away from the electrical connections, wherein variations in the detected second magnetic field provide categories of performance of the electrical connections.