Chromatic Dispersion for Diffuse Surface Thickness Measurement
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Solution Overview
Problem
Existing methods for measuring the surface and thickness of objects, particularly diffuse materials, face inaccuracies due to diffuse reflection, leading to systematic measurement errors and reduced reliability when trying to correct these errors computationally.
Innovation Solution
A measuring device and method utilizing separate transmitter and receiver parts with a dispersive component to disperse optical radiation chromatically in a non-axial direction, focusing different wavelengths on different heights of the object's surface, and using a detector to receive polarized optical radiation from specular reflection, allowing for accurate determination of the surface location and thickness by identifying the wavelength with the highest intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical radiation is used to measure the surface of diffuse materials, then measurement can be performed contactlessly, but diffuse reflection causes systematic measurement errors
Solution Approach 1:
The optical radiation is segmented into different wavelengths, each focusing at different heights above the surface. By analyzing the spectrum of reflected light at different focal positions, the method separates surface reflection signals from internal diffuse reflection signals, enabling accurate surface measurement of diffuse materials.
Solution Approach 2:
The measurement is extended from a single focal plane to multiple focal planes along the optical axis. By focusing different wavelengths at different heights and analyzing the spectral distribution across these planes, the method adds a dimensional aspect to distinguish surface reflection from internal reflection.
2Measurement precision
If computational corrections are applied to account for diffuse reflection, then measurement accuracy may be improved, but measurement reliability reduces due to extensive corrections
Solution Approach 1:
The method replaces computational correction approaches with a physical/optical solution. Instead of using algorithms to correct diffuse reflection errors, the invention uses optical focusing and spectral analysis to physically separate and identify surface reflection signals, maintaining measurement reliability while achieving accuracy.
3Loss of information
If light penetrates deeply into the measured object, then more internal information can be obtained, but surface measurement accuracy decreases due to increased internal reflection
Solution Approach 1:
The method extracts and isolates the surface reflection signal from the total reflected light by analyzing the spectral distribution at different focal positions. By identifying which wavelengths focus at which heights, the system separates surface information from internal reflection information, obtaining pure surface measurement data.
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 effectively reduces diffuse reflection errors, enabling precise measurement of surface and thickness regardless of the material's diffuse nature, maintaining accuracy and reliability without extensive computational corrections.
Implementation Method 1
a dispersive component (400) that is arranged to disperse optical radiation directed to the object being measured (114) chromatically in a non-axial direction
Implementation Method 2
a first focusing component (408) that is arranged to focus the different wavelengths of the non-axially dispersed optical radiation on different heights in the direction of the normal (118) of the surface (116) of the object being measure (114)
Implementation Method 3
a detector (108) to which the second optical radiation processing part (110) of the optical radiation processing unit (112) is arranged to direct the optical radiation that is receivable from the object being measured (114) at least from the direction of specular reflection different from the direction of the normal (118) of the surface being measured (116)
Data Source
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Figure 6
AI summary
An optical radiation processing unit (112) directs different wavelengths of the optical radiation emitted by an optical source (104) to an object (114) being measured from a direction that differs from the normal (118) of a surface (116) being measured in such a manner that the different wavelengths focus on different heights in the direction of the normal (118) of the surface (116) being measured. A possible polarizer (120, 122) polarizes the reflected radiation in a direction perpendicular to the normal (118) of the surface (116). The optical radiation processing unit (112) directs to a detector (108) polarized optical radiation that it receives from the object (114) being measured. The signal processing unit (124) determines on the basis of a signal provided by the detector (112) from the detected radiation the wavelength on which the intensity of the radiation is the highest, and determines the location of the surface (116) by means of the determined wavelength. When measuring an object (114) from both sides, the thickness of the object (114) being measured is determinable using the locations of the surfaces.