Raman Identification Optical System Asymmetry
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Solution Overview
Problem
Existing identification apparatuses using Raman scattering face challenges in maintaining stable identification due to variations in the distance between the apparatus and objects, leading to decreased intensity and sensitivity of Raman-scattered light.
Innovation Solution
The identification apparatus features an illumination optical system and a light capturing optical system with intersecting optical axes, where the illumination optical system has a smaller numerical aperture than the light capturing optical system, ensuring robustness against distance variations and enhancing the intensity and sensitivity of Raman-scattered light detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the illumination optical system and light capturing optical system are coaxial with each other, then the structure is simple, but the intensity of Raman-scattered light decreases greatly when the distance between the identification apparatus and the object varies
Solution Approach 1:
The patent applies asymmetry by making the optical axes of the illumination and light capturing systems intersect at an angle rather than being coaxial. Specifically, the illumination optical system has a smaller numerical aperture than the light capturing optical system, creating an asymmetric configuration that reduces sensitivity to distance variations while maintaining structural feasibility
2Measurement precision
If high-intensity light is used to increase the intensity of Raman-scattered light, then the detection sensitivity improves, but the energy consumption increases
Solution Approach 1:
The patent changes the optical parameters by adjusting the numerical apertures of the illumination and light capturing systems. By setting the illumination system's numerical aperture to be smaller than the light capturing system's, the system optimizes the balance between light intensity and energy consumption, achieving sufficient detection sensitivity without excessive energy use
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 stabilizes the detection of Raman-scattered light, improving the robustness and sensitivity of the identification process even with varying object positions, allowing for accurate identification of resin types.
Implementation Method 1
Raman scattering is used to separate objects such as plastic. The use of the Raman scattering enables the quality of a resin material to be identified
Implementation Method 2
a light capturing optical system that captures Raman-scattered light from the object that is illuminated by the illumination optical system
Implementation Method 3
a spectral element that disperses the Raman-scattered light that is captured by the light capturing optical system
Data Source
AI summary
An identification apparatus identifies the kind of an object to be conveyed by a conveyor and includes an illumination optical system illuminating the object with light from a light source, a light capturing optical system capturing Raman-scattered light from the object, a spectral element dispersing the Raman-scattered light, a light-receiving element receiving the Raman-scattered light dispersed by the spectral element, and a data-processing unit acquiring spectral data of the Raman-scattered light from the light-receiving element and performs an identification process. An optical axis of the illumination optical system and an optical axis of the light capturing optical system intersect each other. The illumination optical system is an imaging optical system that has a numerical aperture for the conveyance surface smaller than that of the light capturing optical system for the conveyance surface, or a collimator optical system that converts the light from the light source into parallel light.