PMMA Optical Probe for Portable Diffuse Reflectance Spectroscopy
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Solution Overview
Problem
Designing a portable diffuse reflectance spectroscopy device is challenging due to miniaturization difficulties, high manufacturing costs, and the complexity of collecting diffuse reflectance from deep tissue, which is hindered by the specular component of reflected light and the intricate process of manufacturing fiber optic probes.
Innovation Solution
A compact, lightweight optical probe made of Poly(methyl methacrylate) (PMMA) with a nested structure that isolates specular reflectance, allowing only diffusely reflected light to be collected, coupled with a micro spectrometer and LED light source for efficient light transmission and shorter integration times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an integrating sphere is used to collect diffuse reflectance light, then light collection efficiency is improved, but device size and weight increase making it non-portable
Solution Approach 1:
The patent extracts the light collection function from the traditional integrating sphere and implements it using a specialized optical probe with multiple fiber optic cables arranged in a specific geometric pattern. This extraction allows the system to achieve effective diffuse reflectance collection while eliminating the bulky sphere structure, enabling portable device design.
Solution Approach 2:
The optical probe employs a nested arrangement where multiple fiber optic cables are positioned concentrically with the source fiber at the center and detection fibers surrounding it. This nested structure maximizes light collection efficiency from deep tissue layers while maintaining a compact probe form factor suitable for portable applications.
2Weight of moving object
If fiber optic probes are used for light transmission, then portability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent employs standardized fiber optic cables that can be used for multiple purposes - both light delivery and light collection. This universal approach simplifies manufacturing by eliminating the need for custom-designed specialized fibers, reducing production complexity and cost while maintaining portability benefits.
Solution Approach 2:
The patent specifies particular geometric parameters for fiber arrangement (concentric circles with specific radii and angular positions) rather than requiring custom fiber designs. This parameter-based specification allows using off-the-shelf fiber optic cables, dramatically simplifying manufacturing while achieving the desired optical performance for portable devices.
3Length of stationary object
If the optical probe collects light from deep tissue, then measurement depth is improved, but specular reflectance interference increases
Solution Approach 1:
The patent extracts and separates the specular reflectance component from the diffuse reflectance signal by using a geometric arrangement where detection fibers are positioned at specific angles and distances from the source. This spatial separation allows the system to collect deep tissue information while minimizing surface specular reflection interference.
Solution Approach 2:
Different regions of the optical probe are assigned different functions: the central source fiber delivers light, while surrounding detection fibers at specific radial distances and angular positions collect diffuse reflectance from different tissue depths. This local differentiation of probe regions enables selective collection of deep tissue signals while rejecting superficial specular reflections.
4Volume of moving object
If a compact optical apparatus is designed for portability, then device size is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise geometric parameters (radii of 1.5mm and 3.0mm, angular positions of 0°, 60°, 120°) for fiber arrangement that can be achieved through standard manufacturing techniques. These parameter specifications enable compact probe design while remaining compatible with conventional fiber bundling and positioning methods, avoiding excessive precision requirements.
Solution Approach 2:
The optical probe is segmented into distinct functional zones with fibers arranged in concentric circles at standardized intervals. This segmentation allows each fiber or fiber group to be positioned and aligned independently using standard techniques, reducing the overall manufacturing precision burden compared to requiring all fibers to be perfectly aligned in a single complex assembly.
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 PMMA optical probe enables easier manufacturing, reduced costs, and efficient light transmission, resulting in a compact, user-friendly device capable of collecting sufficient diffusely reflected light for accurate tissue analysis with shorter integration times.
Implementation Method 1
As the beam penetrates the biological tissue, the direction of propagation changes randomly due to the refractive index variations in the layers beneath. The light is attenuated on its pathway due to the absorption and scattering events.
Implementation Method 2
The light is attenuated on its pathway due to the absorption and scattering events.
Implementation Method 3
A compact, lightweight optical probe made of Poly(methyl methacrylate) (PMMA) with a nested structure that isolates specular reflectance, allowing only diffusely reflected light to be collected
Data Source
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AI summary
The present invention relates to a new optical apparatus for portable diffuse reflectance spectroscopy; and more particularly, relates to a novel optical probe design that is made of Poly(methyl methacrylate) (PMMA) material for the spectroscopic measurement or analysis of biological attributes of tissue.