Switchable Optical Medium for Diffuse Reflectance Spectroscopy
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Solution Overview
Problem
Conventional diffuse reflectance spectroscopy systems with multiple source-detector separations face challenges in accurately measuring optical properties of shallow layers due to larger source-detector separations, inhomogeneity in tissue, and calibration difficulties, requiring a novel approach to overcome these limitations.
Innovation Solution
An optical device with a controllable optical medium that switches between multiple optical states, using a single source-detector separation and two optical fibers, allows for the determination of optical properties by analyzing reflectance spectra obtained from different optical states, eliminating the need for a reference phantom and reducing system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple source-detector separations are used to obtain sufficient information for separating scattering and absorbance properties, then measurement accuracy is improved, but device complexity increases and system size cannot be reduced
Solution Approach 1:
The patent changes the optical properties of the medium itself rather than changing the geometric configuration. By using a medium that can switch between different optical states (different scattering coefficients), the system obtains multiple measurements with different parameters while maintaining a single fixed source-detector separation geometry, thus reducing device complexity while preserving measurement accuracy
Solution Approach 2:
The patent introduces a dynamic optical medium that can switch between different optical states in response to control signals. This dynamic property allows the system to vary its optical characteristics during measurement, enabling multiple measurements with different effective separations using a single fixed physical separation, thereby simplifying the overall system structure
2Loss of information
If larger source-detector separation is used to penetrate deeper layers, then information from deeper layers is obtained, but interference from deeper layers prevents accurate measurement of shallow layers
Solution Approach 1:
The patent uses an optical medium with switchable scattering coefficients to change the effective optical path length dynamically. For shallow layer measurement, the medium is switched to a state with higher scattering coefficient that limits penetration depth, while for deeper layer information, the medium is switched to a state with lower scattering coefficient that allows deeper penetration, thus enabling selective measurement at different depths
Solution Approach 2:
The patent employs periodic switching between different optical states of the medium to acquire multiple measurements with different effective penetration depths. By alternating between high-scattering and low-scattering states, the system periodically samples different depth ranges, allowing separation of contributions from shallow and deep layers through mathematical analysis
3Measurement precision
If multiple light detecting units are used to capture light at different separations, then sufficient information is obtained, but the number of optical fibers and optical switches increases
Solution Approach 1:
The patent makes the optical medium serve multiple functions: it acts as both the measurement medium and the variable parameter controller. The same medium that carries the light also provides the variable scattering property, eliminating the need for separate control mechanisms and reducing the number of optical components required
Solution Approach 2:
The patent merges the function of multiple detecting units into a single detecting unit by combining the variability into the optical medium itself. Instead of having multiple fixed detectors at different positions, the system uses one detector with a dynamically variable medium, combining multiple measurement capabilities into a single integrated component
4Loss of information
If conventional DRS system with multiple source-detector separations is used, then reflectance spectra from different depths are obtained, but calibration becomes difficult due to inhomogeneity in optical properties
Solution Approach 1:
The patent uses a medium with known and controllable scattering coefficients that can be precisely adjusted between different states. This known reference property of the switchable medium provides a stable calibration baseline that is independent of tissue inhomogeneity, making calibration straightforward while still enabling acquisition of reflectance spectra with varying effective penetration depths
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 solution enables accurate and economical measurement of optical properties, specifically absorption and scattering coefficients, with improved calibration and reduced system size, while avoiding interference from deeper tissue layers and simplifying the calibration process.
Implementation Method 1
an optical medium arranged at one end of the device, the optical medium being controllable to switch between multiple optical states and configured to deliver the steady light to the specimen through the optical medium in different optical states
Implementation Method 2
a light beam is directed into a target specimen (such as a biological tissue) and scattered within the specimen. Light diffusely reflected from within the specimen is then captured
Implementation Method 3
Light diffusely reflected from within the specimen is then captured to obtain a reflectance spectrum thereof
Data Source
AI summary
A diffuse reflectance spectroscopy system for determining an optical property of a specimen and a method for operating the same are provided. The system includes: a light emitting unit comprising a light emitting terminal, the light emitting unit configured to emit steady light; an optical medium arranged at one end of the device, the optical medium being controllable to switch between multiple optical states and configured to deliver the steady light to the specimen through the optical medium in different optical states, wherein the optical medium comprises a first surface in contact with the light emitting terminal of the light emitting unit and a second surface for contact with the specimen; and a detecting module comprising one or more receiving terminals for receiving light scattered from the specimen for determining the optical property of the specimen.