Optical Interferometric System for Real-Time Full-Field Thickness Measurement
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Solution Overview
Problem
Conventional optical interferometric systems for real-time full-field thickness measurement of plate-like objects require additional input of average or absolute thickness, necessitating extra time and instruments, as they cannot directly obtain the full-field thickness distribution.
Innovation Solution
An optical interferometric system utilizing two coherent light sources with spherical wavefronts, imaging interference fringe patterns on separate screens, and processing these images to calculate the full-field thickness distribution without the need for additional thickness measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single light source is used for interferometric measurement, then the device complexity is reduced, but the measurement precision of full-field thickness distribution deteriorates because additional instruments are required
Solution Approach 1:
The measurement process is segmented into two independent interferometric measurements using two separate light sources with different incident angles. Each light source captures thickness information from a different perspective, and the image processing module integrates these segmented measurements to reconstruct the complete full-field thickness distribution without requiring external thickness inputs.
Solution Approach 2:
The patent introduces a new dimension by using light sources at different incident angles (different spatial dimensions). The first light source radiates at a first incident angle and the second light source radiates at a second incident angle, creating interference patterns from multiple angular dimensions that together provide complete thickness information.
2Measurement precision
If additional measuring instruments are used to obtain average or absolute thickness, then the measurement precision of thickness distribution is improved, but the productivity deteriorates due to extra measurement time
Solution Approach 1:
The patent merges multiple measurement functions into a single integrated system. Two light sources and two image capturing devices work simultaneously to capture interference patterns, and the image processing module combines these patterns to directly calculate full-field thickness distribution, eliminating the need for separate average thickness measurements and integrating all thickness information acquisition into one real-time process.
Solution Approach 2:
The system maintains continuous real-time measurement capability by using two light sources that simultaneously provide complementary thickness information. The parallel interferometric measurements continue without interruption, and the image processing module continuously processes both interference patterns to generate real-time full-field thickness distribution maps.
3Device complexity
If conventional single-light-source interferometry is used, then the device complexity is low, but the measurement precision deteriorates because it cannot directly obtain full-field thickness distribution
Solution Approach 1:
The patent introduces an image processing module as an intermediary that bridges the gap between the two interferometric measurements and the final thickness distribution result. This module receives interference patterns from two different incident angles, processes them through algorithms that account for the angular differences, and generates the complete full-field thickness distribution map.
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 real-time measurement of full-field thickness without requiring additional instruments or time, providing accurate and direct thickness distribution of plate-like objects.
Implementation Method 1
The first light source is for radiating a first incident light in a first direction toward a reference point located on a surface of the plate-like object to produce a first interference fringe pattern (IFP)
Implementation Method 2
The second light source is for radiating a second incident light in a second direction different from the first direction toward the reference point to produce a second IFP
Implementation Method 3
The first incident light and the second incident light are coherent, have spherical wavefronts, and radiate the plate-like object with the spherical wave fronts
Data Source
AI summary
An optical interferometric system for measurement of a full-field thickness of a plate-like object in real time includes two light sources, two screens, two image capturing devices, and an image processing module. The light sources radiate incident lights toward a reference point on the plate-like object in respective directions to produce respective interference fringe patterns (IFPs). The image capturing devices capture light intensity distribution images respectively of the IFPS imaged respectively on the screens. The image processing module calculates a fringe order at the reference point according to the light intensity distribution images, and obtains a full-field thickness distribution of the plate-like object according to the fringe order.