Optical Analyzer Light Path Length Consistency
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Solution Overview
Problem
Conventional optical analyzers experience measurement errors due to changes in light path length and refractive index when switching between sample and reference measurements, making it difficult to accurately control the concentration of chemicals in semiconductor manufacturing processes.
Innovation Solution
An optical analyzer design that moves a light source unit and light detection unit between sample and reference measurement positions using a support mechanism, maintaining a constant light path length and using a condenser lens to reduce refractive index changes, with a positioning system to ensure accurate alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a pair of reflective mirrors is moved to switch between sample measurement and reference measurement, then the optical analyzer can switch between measurement modes, but the light path length changes causing measurement errors
Solution Approach 1:
The patent merges the light source and condenser lens into a single integrated light source unit that moves together as one assembly. This ensures that the optical path from the light source through the condenser lens to the measurement cell remains constant during mode switching, eliminating measurement errors caused by light path length changes.
Solution Approach 2:
The movable support mechanism serves multiple functions: it positions the light source unit for both sample measurement and reference measurement modes, maintains constant light path length, and ensures proper alignment of optical components. This single mechanism replaces what would otherwise require multiple separate adjustment systems.
2Device complexity
If parallel light is used to irradiate a cylindrical pipe, then the optical setup is simple, but refractive index changes cause measurement errors
Solution Approach 1:
The condenser lens creates a localized convergence of light rays at the measurement point within the pipe, rather than using uniform parallel light across the entire pipe cross-section. This localized focusing reduces the impact of refractive index variations in different regions of the pipe, improving measurement accuracy while maintaining relative simplicity in the optical setup.
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 maintains consistent light path length and reduces refractive index effects, enhancing measurement accuracy and stability in chemical concentration control.
Implementation Method 1
a condenser lens that condenses light from the light source inside the pipe in the sample measurement position
Implementation Method 2
when radiating parallel light or light close to it as in the case of a rectangular cell, a change in refractive index caused depending on the temperature or the concentration of a liquid sample such as a chemical makes it easy to change a light amount detected by a light detector
Data Source
AI summary
The present invention intends to enable light path length to be kept the same between sample measurement and reference measurement and thereby improve measurement accuracy, and is an optical analyzer that analyzes a sample flowing through a pipe having translucency. In addition, the optical analyzer includes: a light source unit that has a light source and a condenser lens; a light detection unit that detects light of the light source unit; and a support mechanism that movably supports the light source unit and the light detection unit. Further, the support mechanism moves the light source unit and the light detection unit between a sample measurement position and a reference measurement position.