Confocal Optical Measurement Device for Skin Depth Isolation
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Solution Overview
Problem
Spectroscopy-based methods for measuring physiological parameters face inaccuracies due to the heterogeneity of skin surface layers, which introduces perturbations and degrades measurement accuracy.
Innovation Solution
An optical measurement device with a pinhole configuration and a control unit is used to selectively receive light rays from a predetermined skin depth, reducing interference from adjacent skin layers by positioning the optical axis to focus on specific skin layers and using pinholes to filter light rays, allowing for precise analysis of physiological parameters like body temperature, bilirubin level, and oxygen saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If spectroscopy is applied by a sensor positioned close to the skin to measure optical properties of surface layers, then non-invasive measurement of physiological parameters is achieved, but heterogeneity of surface layers induces perturbations that degrade measurement accuracy
Solution Approach 1:
The patent divides the skin into multiple depth layers (epidermis, dermis, hypodermis) and uses multiple optical fibers positioned at different depths to measure each layer separately. This segmentation allows selective measurement of the target layer while excluding contributions from other layers, thereby improving measurement accuracy while maintaining non-invasive operation.
Solution Approach 2:
The patent introduces the depth dimension by positioning optical fibers at different skin depths rather than measuring only the surface layer. By measuring at multiple depths and processing the data to isolate the target layer contribution, the system achieves accurate measurement of physiological parameters while maintaining non-invasive operation.
2Measurement precision
If multiple optical fibers are used to measure different skin depths, then measurement accuracy is improved by isolating the layer of interest, but device complexity increases
Solution Approach 1:
The patent uses a single multi-functional optical measurement device that can measure multiple skin layers and multiple physiological parameters (temperature, oxygen saturation, bilirubin) simultaneously. This universal device eliminates the need for separate specialized devices for each measurement type, thereby reducing overall system complexity while maintaining high measurement precision for each parameter.
Solution Approach 2:
The patent combines multiple optical fibers measuring different skin depths into a single integrated measurement system with unified data processing. By merging the measurement functions and processing the combined data to isolate target layer contributions, the system achieves layer-specific accuracy without requiring separate complex devices for each depth measurement.
3Measurement precision
If numerical correction factors are used to compensate for parasitic radiations, then measurement accuracy is improved, but computational complexity and processing time increase
Solution Approach 1:
The patent performs preliminary measurements at multiple skin depths before final analysis. By collecting depth-resolved data in advance and using it to calculate correction factors, the system prepares the necessary information for accurate measurement without requiring complex real-time calculations during the actual measurement, thereby reducing processing time while maintaining accuracy.
Solution Approach 2:
The patent measures optical properties at multiple depths (excessive measurement) beyond the single depth needed for the final result. This excessive measurement provides redundant data that simplifies the correction process by allowing direct subtraction or ratio calculations to eliminate parasitic radiation effects, reducing the need for complex iterative computations and thereby reducing processing time.
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 method enhances measurement accuracy by isolating the desired skin depth, reducing parasitic radiation interference and improving the precision of physiological parameter determination.
Implementation Method 1
an optical objective (3) focusing the radiations emitted by the biological tissue (10)
Implementation Method 2
a first pinhole (11) positioned in a first confocal plane cF1 which is the conjugate, through the objective (3), of the focal plane (F)
Implementation Method 3
a photosensitive detector (4) adapted for detecting the radiations coming from the focal plane (F)
Implementation Method 4
a semi-reflective planar mirror (5) positioned between the light source (2) and the biological tissue (10), said mirror being configured for transmitting the light rays emitted by the light source towards the optical objective (3), and for reflecting the light rays from the first object focal spot towards the photosensitive detector (4)
Data Source
AI summary
The present invention relates to a method for measuring a physiological parameter of a subject by means of an optical measurement device, said method comprising the steps of:setting into place the optical measurement device (1, 1bis) facing a skin surface (10) of the subject, so that the object focal spot of the optical objective is positioned at a predetermined skin depth,receiving by the photosensitive receiver (4) light rays from the first object focal spot, at the predetermined skin depth,analyzing the light rays received by the photosensitive receiver (4), and comparing the results of the analysis with known data, so as to determine the physiological parameter of the subject.