Wavelength-Selective Optical Testing for Quantifying Refractive Index
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Solution Overview
Problem
Conventional contactless test apparatuses using schlieren methods struggle to quantitatively measure the magnitude of refractive index or scattering, limiting their ability to provide accurate measurements.
Innovation Solution
An optical test apparatus with a first and second aperture, each with wavelength-selecting regions, and an image sensor to image light beams passing through these apertures, allowing for the measurement of deflection angles caused by a test object, thereby estimating refractive index distribution and scattering intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional schlieren methods are used for contactless testing, then the presence or absence of refractive index distribution or scattering can be discriminated, but the magnitude of refractive index or scattering cannot be quantitatively measured
Solution Approach 1:
The aperture is divided into multiple wavelength-selecting regions, each corresponding to different deflection angle ranges. By segmenting the aperture into distinct zones that select different wavelengths, the system can map deflection angles to specific wavelength bands, enabling quantitative measurement of refractive index magnitude rather than just presence detection
Solution Approach 2:
The invention utilizes wavelength (color) as a carrier of measurement information. Different wavelength regions in the aperture correspond to different deflection angle ranges, allowing the system to encode quantitative refractive index information into the spectral composition of transmitted light, thereby recovering magnitude information that was lost in conventional binary schlieren methods
2Measurement precision
If a single aperture is used, then the device structure remains simple, but the ability to measure deflection angles and estimate refractive index distribution is limited
Solution Approach 1:
The aperture is segmented into multiple wavelength-selecting regions with different transmission characteristics. Each region is designed to transmit specific wavelength bands that correspond to particular deflection angle ranges, enabling the system to capture spatial distribution information of refractive index through spectral analysis
Solution Approach 2:
The multi-region aperture serves multiple functions simultaneously: it acts as a spatial filter, a spectral filter, and a measurement encoder. By integrating these functions into a single aperture component, the system achieves sophisticated refractive index distribution measurement without proportionally increasing device 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 accurate, contactless quantification of refractive index and scattering intensity by imaging light beams deflected by the test object, providing detailed information about the object's properties.
Implementation Method 1
measure deflection angles caused by a test object, thereby estimating refractive index distribution
Implementation Method 2
estimating refractive index distribution and scattering intensity
Data Source
AI summary
According to one embodiment, an optical test apparatus includes a first aperture, a second aperture, an image sensor, and a first lens. The first aperture includes a first aperture plane provided with a first wavelength selecting region. The second aperture includes a second aperture plane provided with a second wavelength selecting region different from the first wavelength selecting region. The image sensor is configured to image a light beam passing through the first aperture plane and the second aperture plane and reaching an imaging plane. The first lens is configured to make a light beam passing through the first aperture plane and the second aperture plane be incident on the imaging plane.