Rotatable Light Trap for Integrating Sphere Specular Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional integrating sphere devices have limitations such as fixed angles for diffuse reflectance measurements with the specular component excluded, non-uniform reflectance of filler plugs, and less accurate radiance measurements for highly mirror-like surfaces when the specular region is aligned with a non-uniform filler plug.
Innovation Solution
A light integrating cavity device with a rotatable light trap within the light scattering cavity, allowing the light trap to be positioned in specular alignment with the sample and measurement device to prevent specular reflections, enabling variable-angle measurements with or without the specular component, and accommodating different sample configurations using a 'partial sphere' setup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a filler plug is used in place of the light trap to measure diffuse reflectance including the specular component, then the measurement can be performed, but the reflectance of the filler plug may not be uniformly matched to the sphere wall and the radiance for highly mirror-like surfaces may be less accurately measured
Solution Approach 1:
The light trap is made rotatable within the light scattering cavity, allowing dynamic repositioning between specular alignment and other positions. This enables the same device to perform both specular-included and specular-excluded measurements without requiring multiple static configurations or filler plugs, thereby improving adaptability while maintaining measurement precision through consistent optical characteristics.
2Measurement precision
If a specular hole is provided through the sphere aligned to the position where the specular component originates, then the specular component can be excluded, but only fixed angles of diffuse reflectance can be measured
Solution Approach 1:
The rotatable light trap enables dynamic adjustment of the specular exclusion alignment. By rotating the light trap to different angular positions, the device can exclude specular components at various angles while maintaining the ability to measure diffuse reflectance at different angles, thus achieving both precise specular exclusion and angular flexibility.
Solution Approach 2:
The rotatable light trap serves multiple functions: it can be positioned to exclude specular components at any angle, and can also be positioned to include specular components for comprehensive measurements. This single component replaces the need for multiple fixed holes or plugs, providing universal functionality for various measurement configurations.
3Measurement precision
If the light trap is positioned in specular alignment to prevent specular reflections, then the specular component can be excluded, but the device complexity increases
Solution Approach 1:
The light trap is mounted on a rotatable mechanism that allows simple angular adjustment. This dynamic positioning capability provides precise specular component control through a straightforward rotational motion, avoiding the need for complex multi-component alignment systems while achieving accurate specular exclusion at any desired angle.
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 solution allows for more accurate and flexible diffuse reflectance and transmittance measurements by eliminating the need for a light trap aperture plug, providing uniform luminance distribution and enabling measurements with or without the specular component, thus overcoming the limitations of conventional integrating sphere devices.
Implementation Method 1
The interior of the shell is covered with a diffusely reflecting coating. Light rays incident on any point on the inner surface are scattered via diffuse reflection.
Implementation Method 2
A light trap is provided that is mounted within the LSC and is rotatable to be in a specular optical alignment with the sample and the LMD, so as to prevent the LMD from receiving specular reflections from the sample.
Data Source
AI summary
The invention relates to a light integrating cavity device, such as an integrating sphere, for measuring diffuse reflectance of a sample. A light trap is movable within a light scattering cavity of the device for controlling specular reflections during measurements. The light trap may be rotatable around the sample under test inside the cavity so that specular reflections off the sample can be included or excluded from the measurement. The sample may also be placed at the outside against a measurement port, and a measurement instrument is moveable on a rotating arm within or outside of the cavity.