Compact NIR Spectrometer with Integrated Collimator-Grating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Spectrometer-based optical coherence tomography systems face challenges in achieving mechanical stability and environmental stability, particularly in high-resolution imaging and mobile applications, due to alignment issues and susceptibility to thermal and mechanical perturbations.
Innovation Solution
A compact diffraction-limited spectrometer design with a fixed focus collimator assembly and imaging lens assembly, utilizing a single piece of low thermal expansion material for both grating and collimating lens mounting, and a Cooke triplet variant lens configuration to maintain alignment and reduce thermal expansion effects, along with a detector array interface for adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a highly dispersive element with optics providing constant magnification imaging is used for high resolution spectrometer, then imaging resolution is improved, but manufacturing complexity and environmental stability are worsened
Solution Approach 1:
The patent combines the collimating lens and diffraction grating into a single integrated element. The collimating surface and grating lines are formed on the same optical component, eliminating the need for separate alignment of multiple elements. This merging maintains diffraction-limited imaging performance while dramatically simplifying manufacturing and improving environmental stability, as the integrated element cannot suffer from misalignment between separate components.
2Reliability
If active control mechanisms are added to adjust alignment in spectrometer, then environmental stability is improved, but device complexity is worsened
Solution Approach 1:
The patent employs passive athermalization techniques where the optical system is designed to automatically compensate for thermal expansion and environmental changes without active control. By selecting materials with matched thermal expansion coefficients and designing the optical path to be inherently stable, the system maintains alignment stability passively, eliminating the need for active adjustment mechanisms while preserving environmental stability.
3Volume of moving object
If optical path length is reduced for compact spectrometer design, then device size is improved, but alignment sensitivity to environmental perturbation is worsened
Solution Approach 1:
The integrated collimating lens-grating element reduces the number of optical interfaces and alignment points in the compact spectrometer design. By combining functions into fewer elements, the system minimizes the cumulative alignment sensitivity that would normally worsen with reduced spacing, maintaining stability despite the compact form factor.
Solution Approach 2:
The optical design incorporates athermalization features that allow the compact spectrometer to automatically compensate for thermal effects. Material selection and optical path design ensure that the reduced physical dimensions do not compromise alignment stability, as the system self-adjusts for environmental changes without requiring active 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
The design achieves long-term alignment stability and improved image quality by reducing mechanical sensitivity and maintaining focus over large temperature ranges, enabling high-resolution imaging with reduced optical path length and enhanced mechanical stability.
Implementation Method 1
a diffraction grating; wavelength diverse optical radiation incident thereon
Implementation Method 2
an imaging lens assembly coupled to the detector array
Implementation Method 3
a collimating lens assembly providing collimated light from an optical radiation input fiber to the diffraction grating
Data Source
AI summary
Spectrometer systems are provided including a detector array; an imaging lens assembly coupled to the detector array, the imaging lens assembly including a first element of positive optical power followed by a second element of negative optical power and a positive optical power element split into two opposing identical singlets; a dispersive element coupled to the imaging lens assembly; and a fixed focus collimator assembly coupled to the dispersive element. Related imaging lens assemblies and collimator assemblies are also provided.