Grating Photometer Stray Light Suppression via Extinction Holes
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Solution Overview
Problem
Stray light from the zero order spectrum in grating photometric systems interferes with signal detection, reducing accuracy and analytical sensitivity due to insufficient suppression by existing methods.
Innovation Solution
A grating photometer design featuring a light splitting box with a first through extinction hole and a second blind extinction hole, connected by a through hole in a sealing gasket, directs the zero order spectrum away from the light splitting chamber, effectively reducing stray light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional methods (concave grating or black extinction paint) are used to reduce stray light, then the number of optical elements is minimized or the vessel surface is treated, but the stray light from zero order spectrum cannot be suppressed sufficiently
Solution Approach 1:
The light splitting chamber is divided into multiple regions by partition walls with extinction holes at specific positions. The zero order spectrum is segmented and directed into dedicated extinction holes, separating it from the main light path and preventing it from forming stray light in the detection area.
Solution Approach 2:
Extinction holes serve as intermediary structures that capture and redirect the zero order spectrum. These holes act as mediators between the grating and the detection area, intercepting the harmful zero order light before it can interfere with the measurement signal.
2Device complexity
If the light splitting chamber is simplified to reduce stray light, then fewer optical elements are used, but the stray light from zero order spectrum increases
Solution Approach 1:
Instead of uniformly treating the entire light splitting chamber, extinction holes are strategically positioned only at locations where zero order spectrum emerges. This localized approach addresses the stray light problem at specific critical points without requiring complex modifications throughout the entire system.
Solution Approach 2:
The solution moves from a two-dimensional surface treatment (black paint coating) to a three-dimensional structural approach with extinction holes penetrating through partition walls. This dimensional transition allows for more effective stray light suppression by creating depth-based light path control.
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 configuration significantly minimizes stray light, enhancing the signal-to-noise ratio and improving analytical sensitivity.
Implementation Method 1
a first ejection hole and a second extinction hole are provided respectively on the side wall of the light splitting chamber and on the preamplifier box respectively which correspond to the position of the zero order spectrum line
Data Source
AI summary
The present invention provides a grating photometer comprising a light splitting box, a preamplifier box, a photodiode array and optical assembly. The light splitting box has a light splitting chamber. There are provided a first extinction hole and second extinction hole respectively on the side wall of the light splitting chamber and on the preamplifier box to correspond to zero order spectrum line. The first hole is a through hole and the second hole is a blind hole. The configuration of the first and second extinction holes direct the zero order spectrum to go into the second extinction hole, as a result, generates a rather small number of stray light in the light splitting chamber coming from the scattering of the zero order spectrum from the second extinction hole, thus suppresses effectively the stray light and improves the signal-to-noise ratio of the photometer.