Reflectometry-Based Inspection of PCB Signal Transmission Lines
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Solution Overview
Problem
Conventional X-ray inspection methods for RF passive components are inefficient and inaccurate due to the need for visual analysis, which takes a long time and often fails to detect defects in signal transmission lines accurately.
Innovation Solution
An apparatus with a reflectometry unit that computes frequency-based and time-based reflection coefficient values to determine defects and their locations in signal transmission lines on printed circuit boards, using a network analyzer and processor-based defect detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional X-ray inspection method with visual analysis is used, then defect detection capability is provided, but inspection time becomes excessively long
Solution Approach 1:
The patent replaces the manual visual inspection system with an automated reflectometry-based measurement system. The network analyzer automatically measures reflection coefficients and processes the data to detect defects, eliminating the need for human visual analysis of X-ray images while maintaining defect detection capability.
Solution Approach 2:
The patent introduces reflection coefficient measurements as an intermediary parameter between the physical defect and the detection result. Instead of directly visualizing the defect through X-ray images, the system measures electrical reflection characteristics that are sensitive to defects, enabling automated and quantitative defect detection.
2Reliability
If conventional X-ray inspection method with visual analysis is used, then defect detection is performed, but measurement precision becomes insufficient
Solution Approach 1:
The patent replaces the subjective human visual analysis system with an automated electronic measurement and processing system. The network analyzer and computer automatically measure reflection coefficients and apply signal processing algorithms, eliminating human subjectivity and improving measurement precision and repeatability.
Solution Approach 2:
The patent uses reflection coefficient measurements as a sensitive intermediary that amplifies the effect of small defects. Electrical reflection measurements are highly sensitive to changes in transmission line characteristics caused by defects, enabling more precise detection compared to visual X-ray analysis.
3Productivity
If automated reflectometry-based inspection is used, then inspection speed is improved, but device complexity increases
Solution Approach 1:
The patent uses a network analyzer, which is a multi-functional instrument capable of performing various RF measurements including reflection coefficient measurements. This universal instrument can inspect different types of transmission lines and components, reducing the need for multiple specialized devices and thereby managing complexity.
Solution Approach 2:
The patent introduces reflection coefficient measurements as an intermediary parameter that automatically indicates the presence and location of defects. This electrical measurement approach provides direct, quantifiable data that simplifies the inspection process compared to visual analysis, enabling faster automated inspection despite the added measurement complexity.
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 rapid and accurate inspection of RF passive components by analyzing reflection coefficients, reducing inspection time and improving defect detection accuracy compared to conventional methods.
Implementation Method 1
a reflectometry unit configured to input an incident signal to an input port connected to the signal transmission line, receive a reflected signal in response to the incident signal through the input port
Data Source
AI summary
An apparatus for inspecting a passive component having a signal transmission line on a printed circuit board (PCB), includes a reflectometry unit for inputting an incident signal to an input port connected to the signal transmission line, receiving a reflected signal in response to the incident signal, and computing a plurality of frequency-based reflection coefficient values in a preset frequency range and a plurality of time-based reflection coefficient values in a preset time range based on the incident signal and the reflected signal; and a defect detection unit for determining whether the signal transmission line has a defect based on the plurality of frequency-based reflection coefficient values, and determining a location of the defect on the signal transmission line based on the plurality of time-based reflection coefficient values.