Laser Line Vision System for Substrate Displacement Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for detecting substrate displacement in manufacturing processes, such as machine vision systems and laser displacement sensors, face challenges like high error rates due to specular reflection and the need for expensive sensor arrays, which are slow and prone to positioning errors, especially when substrates are moved along a conveyor.
Innovation Solution
A system using a laser line and an image sensor connected to a vision system processor generates a range image with height information, allowing for accurate detection of substrate displacement by comparing height differences to predetermined parameters, even in the presence of specularity, and compensating for missing data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser displacement sensors are arrayed to accurately determine substrate orientation, then measurement precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent transitions from point-based measurements (1D/2D) to a line-based measurement approach (3D). By projecting a laser line onto the substrate and capturing it with a linear array sensor, the system obtains continuous height information along the entire line simultaneously, eliminating the need for multiple discrete sensors and achieving full 3D surface profiling in a single measurement.
Solution Approach 2:
The patent creates an optical copy of the substrate surface by projecting a laser line pattern onto it and capturing the reflected light with an image sensor. This optical copying process generates a digital elevation map that represents the physical surface topology, allowing non-contact measurement of substrate orientation and displacement without physical sensor contact.
2Measurement precision
If laser profiling is used to measure substrate profile, then measurement precision is improved, but productivity decreases due to slow measurement speed
Solution Approach 1:
The patent implements continuous measurement capability by using a laser line that spans the entire substrate width and a linear array sensor that captures all height information simultaneously. This allows the system to measure the complete substrate profile in a single snapshot as the substrate moves along the conveyor, maintaining measurement accuracy while enabling high-speed continuous operation without sequential scanning delays.
3Productivity
If light curtains are used for substrate detection, then measurement speed is improved, but measurement precision deteriorates due to tolerance errors and variability
Solution Approach 1:
The patent replaces the rigid, fixed-height mechanical light curtain system with a flexible laser line projection system. The laser line can adapt to varying substrate positions and heights, while the image sensor captures the actual reflected light pattern to determine precise substrate location. This substitution eliminates the tolerance errors inherent in fixed mechanical structures while maintaining high detection speed.
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
This approach provides fast and accurate detection of substrate displacement without contact, reducing errors and operational costs, and enabling continuous monitoring on a moving production line.
Implementation Method 1
A system uses a laser line free of contact with an object and received by an image sensor
Implementation Method 2
received by an image sensor, which is operatively connected with a vision system processor
Data Source
AI summary
A system and method for detecting and/or determining the existence of displacement of a substrate with respect to a surrounding object uses a laser line that is free of contact with the object and that is received by an image sensor. A processor reads the line information in a series of image frames, and generates a range image with height information. The height information is provided to a 2D map. Differences between adjacent height measurements, and averages, are computed. Vision system tools are used to accurately locate features in the image and these are aligned with the height information. The height differences are interpreted, with missing height data due, for example, to specularity in the image being approximated. The height differences are compared to predetermined height parameters relative to identified locations, for example, wells, in the object to determine whether a substrate is displaced.