Flexible Probe Fingers for Fine-Pitch Electrical Testing
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Solution Overview
Problem
Existing multi-electrode probes, such as those using pogo pins, are limited in precision and resolution due to their size and material constraints, hindering the ability to scale down pitch and size for fine-pitch electrical measurements in complex electronic devices like LCD panels.
Innovation Solution
A probe design featuring a ceramic substrate with BeCu fingers that extend beyond the substrate, flex within a recess, and are held by an assembly with a limiter and spring mechanism, allowing for precise contact and measurement with improved precision and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pogo pins are used for electrical testing, then mechanical contact is achieved, but the probe size and pitch cannot be scaled down below a few hundred microns
Solution Approach 1:
The patent replaces the traditional mechanical pogo pin system with a flexible printed circuit board (FPC) based probe system. The FPC allows for extreme miniaturization while maintaining electrical contact capability, enabling probe pitches in the micrometer range rather than hundreds of micrometers. The flexibility of the FPC provides the necessary compliance for contact without requiring bulky mechanical spring mechanisms.
Solution Approach 2:
The patent utilizes a flexible printed circuit board as the core component, which is a thin, flexible film structure. This flexible film approach enables the probe to achieve both small size and the necessary mechanical compliance for electrical contact. The FPC can be bent and deformed to accommodate contact requirements while maintaining a extremely small form factor and fine pitch dimensions.
2Measurement precision
If pogo pins with spring preloading are used, then contact force is maintained, but the probe cannot achieve fine-pitch measurements
Solution Approach 1:
The patent replaces the spring-loaded mechanical pogo pin system with an FPC-based system where contact force is achieved through the inherent flexibility and elasticity of the flexible circuit board material. This substitution eliminates the need for discrete spring components and allows for much finer pitch dimensions, enabling measurements in the micrometer range rather than hundreds of micrometers.
Solution Approach 2:
The patent changes the fundamental parameters of the probe system by transitioning from rigid metal pins with mechanical springs to a flexible polymeric circuit board. This parameter change in material composition and structural flexibility enables both fine-pitch capability and adequate contact force, resolving the contradiction between measurement precision and pitch size.
3Ease of manufacture
If plastic carriers are used for mounting probes, then assembly is simplified, but precision and resolution are limited
Solution Approach 1:
The patent replaces rigid plastic carriers with a flexible printed circuit board that integrates both the mounting function and the electrical connection function. The FPC can be precisely manufactured using standard flexible circuit board fabrication processes, achieving high precision in probe positioning and orientation while maintaining ease of assembly through the inherent flexibility that allows for self-alignment and accommodation of manufacturing tolerances.
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 fine-pitch electrical measurement applications with enhanced precision and resolution, suitable for devices like smart watches and smartphones, improving the detection of defects in complex electronic devices.
Implementation Method 1
at least one spring disposed between the substrate and the assembly in the assembly recess
Data Source
AI summary
A fine electrical probe can provide fine-pitch applications in devices such as smart watches and smart phones. Fingers are positioned on a substrate. The substrate has a recess that allows the fingers to flex. The substrate and fingers are positioned in an assembly. The assembly has a recess that allows the substrate to flex.