Spatially Variable Filter Optical Profilometer for 3D Surface Profiling
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Solution Overview
Problem
There is a need for instrumentation capable of accurately measuring film thickness and surface profiles of samples in the field of optical instrumentation, particularly for three-dimensional structures with varying surface profiles, where existing methods lack precision and efficiency.
Innovation Solution
The development of optical profilometers incorporating vertical scanning interferometry and confocal microscopy configurations, combined with spatially variable filters, enables non-contact measurement of surface profiles by utilizing interference patterns and spatially varying spectral properties to enhance measurement accuracy and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical measurement methods are used, then the measurement process is simple, but the measurement precision and resolution are insufficient for three-dimensional structures with varying surface profiles
Solution Approach 1:
The optical system is segmented into multiple functional components including vertical scanning interferometry module, confocal microscopy module, and spatially variable filter. Each module performs a specific function (interference pattern generation, focal plane detection, spectral filtering) that collectively achieves high measurement precision for three-dimensional structures without requiring a single overly complex device
Solution Approach 2:
The patent employs spatially variable filters that provide different spectral properties at different positions within the optical path. This local variation in filter characteristics enables optimized measurement for different regions of the sample, improving overall measurement precision while maintaining a manageable device architecture through targeted functional differentiation
2Manufacturing precision
If spatially variable filters are incorporated into the optical system, then the resolution and contrast are enhanced, but the device complexity increases
Solution Approach 1:
The spatially variable filter is designed to perform multiple functions simultaneously: it provides spectral filtering, enhances image contrast, and enables depth discrimination. This multi-functionality allows a single component to achieve multiple measurement objectives, improving resolution without requiring separate devices for each function and thereby limiting the increase in overall device complexity
3Measurement precision
If vertical scanning interferometry and confocal microscopy are combined, then the measurement accuracy is improved, but the device complexity and operational complexity increase
Solution Approach 1:
The patent merges vertical scanning interferometry and confocal microscopy into a single integrated optical system that shares common components (light source, objective lens, detector). This combination allows both measurement techniques to operate simultaneously or sequentially using the same hardware platform, improving measurement accuracy through complementary mechanisms while reducing operational complexity compared to managing separate systems
Solution Approach 2:
The spatially variable filter acts as an intermediary element that mediates between the interferometry and confocal microscopy pathways. It provides spectral discrimination that enhances the performance of both techniques while simplifying the control and data processing requirements, thereby improving measurement accuracy without proportionally increasing operational 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
These systems provide precise measurements of film thickness and surface profiles, offering improved resolution and contrast, particularly suited for three-dimensional imaging and profiling, with enhanced accuracy and efficiency compared to conventional methods.
Implementation Method 1
utilizing interference patterns and spatially varying spectral properties to enhance measurement accuracy and resolution
Data Source
AI summary
A system comprising a light source, and a retention device configured to receive and retain a sample for measurement. The system includes a detector. An optical path couples light between the light source, the sample when present, and the detector. An optical objective is configured to couple light from the light source to the sample when present, and couple reflected light to the detector. A controller is configured to automatically control focus and/or beam path of the light directed by the optical objective to the sample when present. The system includes a spatially variable filter (SVF) positioned in the optical path. The SVF is configured to have spectral properties that vary as a function of illuminated position on the SVF.