Grazing Incidence Interferometer Scanning Measurement
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Solution Overview
Problem
Grazing incidence interferometers face limitations in widening their measurement range while maintaining high accuracy, as increasing the incident angle reduces resolution, and existing scanning measurement methods complicate the instrument configuration and increase costs.
Innovation Solution
A scanning measurement method that uses elements of the optical system for both surface texture measurement and posture detection, allowing for wider measurement ranges with improved accuracy by integrating the measurement and auxiliary optical systems, and employing a moving mechanism to connect measurement sections with precise position and posture correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the incident angle of measurement light is increased to widen the measurement area, then the measurement area is widened, but the measurement resolution lowers
Solution Approach 1:
The patent divides the measurement process into multiple sections by moving the interferometer across the measurement subject. Each section is measured independently with optimal incident angle for resolution, and then the sections are connected through calculation. This segmentation allows the system to achieve both wide measurement area and high resolution by measuring smaller regions with high precision and then stitching them together.
Solution Approach 2:
The patent introduces a moving dimension to the measurement system. Instead of increasing the incident angle to widen the measurement area (2D parameter change), the system moves the interferometer along the measurement subject (adding a spatial dimension). This dimensional transition allows the measurement area to be widened without compromising resolution, as each local measurement maintains optimal optical parameters.
2Area of stationary object
If a scanning measurement method is applied to measure the entire measurement surface, then the measurement range is widened, but the instrument configuration becomes more complex
Solution Approach 1:
The patent makes the interferometer system multi-functional by enabling it to perform both local high-precision measurements and wide-range scanning measurements. The same interferometer unit, when moved to different positions, can measure different sections of the measurement subject. This universality eliminates the need for multiple separate interferometers or complex additional systems, as a single instrument can handle both local and wide-area measurement tasks through simple repositioning.
3Measurement precision
If another interferometer is prepared to measure the posture of the scanning interferometer, then the connection accuracy between measurement sections is improved, but the cost and device complexity increase
Solution Approach 1:
The patent enables the scanning interferometer to self-determine its own posture and position during movement. By equipping the interferometer with position detection capabilities (such as encoders or other sensing mechanisms), the system can independently measure its own state without requiring an external reference interferometer. This self-service approach maintains connection accuracy between measurement sections while eliminating the need for additional interferometric equipment.
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 high-accuracy, wide-range measurement of large, non-specular surfaces without the need for additional interferometers, simplifying the instrument configuration and reducing costs by sharing optical elements for both measurement and posture detection.
Implementation Method 1
a light source configured to generate coherent original light
Implementation Method 2
a light beam divider configured to divide the original light coming from the light source into measurement light and reference light
Implementation Method 3
an illuminator configured to apply the measurement light obliquely to a measurement subject surface of a measurement subject
Implementation Method 4
the measurement light reflected from the measurement subject surface
Implementation Method 5
a light beam combining module configured to combine the measurement light reflected from the measurement subject surface with the reference light
Implementation Method 6
a photodetector configure to detect a combined light beam produced by the light beam combining module
Implementation Method 7
a moving mechanism mounted on the stage, and configured to support the interferometer main body and to be capable of moving the interferometer main body along the measurement subject
Data Source
AI summary
A grazing incidence interferometer includes a light source, a light beam divider configured to divide original light coming from the light source, an illuminator configured to apply measurement light to a measurement subject, a light beam combining module configured to combine the measurement light reflected from the measurement subject with reference light, and a photodetector configure to detect a combined light beam. The grazing incidence interferometer includes an interferometer main body, a stage configured to hold the measurement subject, a moving mechanism capable of moving the interferometer main body along the measurement subject, and an auxiliary reflector disposed on an extension of an axis of movement of the interferometer main body, an auxiliary light beam separator configured to separate auxiliary light from the original light and to apply the auxiliary light to the auxiliary reflector, and an auxiliary photodetector configured to detect the auxiliary light reflected by the auxiliary reflector.