Hollow Sphere Grazing-Angle Measurement for Rapid Reflectance Testing
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Solution Overview
Problem
Measuring the spectral hemispherical reflectance of a sample, particularly at high angles of incidence, is complex and labor-intensive due to the need for single-angle measurements and potential sources of error in existing devices.
Innovation Solution
A system utilizing a hollow sphere with a rotatable mounting arm and reflective elements, including galvanometers and parabolic mirrors, to rapidly measure reflectance across various angles without replacing the sample, using the sphere's interior surface as a reference for correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If single angle measurements are used with interior surface reference, then measurement accuracy is improved, but measurement time and labor increase substantially
Solution Approach 1:
The system employs a rotatable hollow sphere that can dynamically change its rotational position between multiple predetermined positions, enabling the measurement beam to access different angular positions. This dynamic rotation allows rapid switching between measurement angles without manual intervention, resolving the contradiction by making the measurement system adaptable and fast while maintaining accuracy through the interior surface reference method
Solution Approach 2:
The system implements periodic rotation of the hollow sphere through a series of predetermined angular positions, allowing systematic collection of reflectance data at multiple angles. This periodic action enables comprehensive angular coverage while maintaining consistent measurement conditions at each position, achieving both speed and accuracy
2Adaptability or versatility
If multiple angles of incidence are measured, then comprehensive reflectance data is obtained, but measurement complexity increases
Solution Approach 1:
The hollow sphere serves multiple functions simultaneously: it acts as a reference surface (using its interior surface), a positioning mechanism (through rotation to predetermined angles), and a protective enclosure. This multi-functionality reduces overall system complexity while enabling measurements at multiple angles of incidence, resolving the contradiction between versatility and complexity
Solution Approach 2:
The hollow sphere acts as an intermediary element that mediates between the fixed measurement apparatus and the sample. By rotating the sphere to different positions, it provides a systematic way to achieve multiple measurement angles without requiring complex reconfiguration of the entire measurement system, thereby reducing complexity while maintaining angular versatility
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 rapid and accurate measurement of spectral hemispherical reflectance at high angles of incidence, reducing measurement noise and labor by eliminating the need for sample substitution and accounting for error sources.
Implementation Method 1
a series of reflective elements configured to direct the beam of light from the laser
Implementation Method 2
a hollow sphere rotatable about a sphere axis with the sphere axis extending through a central region of the hollow sphere
Implementation Method 3
a spectral hemispherical reflectance detector including a field of view extending into the hollow sphere
Data Source
AI summary
A system for performing grazing angle measurements is disclosed herein. The system includes a laser configured to emit a beam of light and a series of reflective elements configured to direct the beam of light and a hollow sphere is rotatable about a sphere axis with the sphere axis extending through a central region of the hollow sphere. The hollow sphere defines an elongated slot for accepting the beam of light when the hollow sphere is in one of a plurality of predetermined rotational positions about the sphere axis. A mounting arm extends into a central region of the hollow sphere and includes a sample mount configured to receive a sample. The system further includes a spectral hemispherical reflectance detector having a field of view extending into the hollow sphere and a baffle horizontally interposed relative to the sphere axis between the spectral hemispherical reflectance detector and the elongated slot.