Optical Oximeter Contact Surface to Suppress Light Piping
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Solution Overview
Problem
State-of-the-art oximeters suffer from insufficient precision and accuracy, particularly when measuring optical parameters in scattering media like human tissue, due to light piping through layers such as air and sweat, which violate semi-infinite boundary conditions and affect measurement accuracy.
Innovation Solution
The apparatus incorporates optical barriers on the contact surface to suppress light propagation through layers between the oximeter and the tissue, using structures that block, redirect, or absorb light, and limits emission and reception angles to minimize light piping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light sources and detectors are placed in direct contact with tissue, then measurement sensitivity is improved, but light piping through air and sweat layers causes measurement inaccuracy
Solution Approach 1:
The patent introduces an optical coupling medium (gel or liquid) as an intermediary substance between the contact surface and tissue. This medium fills air gaps and sweat layers, eliminating light piping while maintaining good optical coupling for accurate measurements.
Solution Approach 2:
The patent extracts and removes the harmful air and sweat layers between the contact surface and tissue by applying pressure or using the optical coupling medium to displace these interfering substances, thereby eliminating the light piping effect.
2Measurement precision
If optical barriers are added to suppress light piping, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the optical barrier function directly into the contact surface structure itself, making the barriers integral to the housing rather than separate components. This integration reduces device complexity while maintaining the light piping suppression function.
3Object-affected harmful factors
If multiple optical barriers are used to block light piping, then light suppression is improved, but light intensity reaching detectors decreases
Solution Approach 1:
The patent applies optical barriers selectively only in regions where light piping occurs (between light sources and detectors), rather than covering the entire contact surface. This localized approach suppresses light piping while preserving maximum light intensity for measurements.
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 approach significantly improves measurement accuracy by reducing the proportion of photons that travel outside the tissue, allowing for precise determination of optical properties and tissue oxygen saturation, especially in deep layers.
Implementation Method 1
using structures that block, redirect, or absorb light
Implementation Method 2
using structures that block, redirect, or absorb light
Implementation Method 3
limits emission and reception angles to minimize light piping
Implementation Method 4
light transport can be modelled by a diffusion process
Implementation Method 5
light emitted by a source can reach a detector by propagating through the layer through multiple reflections at the boundaries of the layer
Data Source
Figure 1~4
Figure 5~10
Figure 11~14
AI summary
A spectrophotometric apparatus (1) is proposed for determining optical parameters in a scattering medium (4) based on the measurement of attenuation of light propagating through said medium (4) by diffusion. To eliminate the detrimental effect of light being guided in an intermediate optical layer (25) between a surface (23) of the medium (4) and a contact surface (8) of the apparatus (1), either a multitude of optical barriers (4) may be formed in the contact surface (8) or the angular range over which light is emitted or received by the apparatus (1) may be limited by appropriate means (13). With both of these alternative approaches, light propagation in the intermediate layer (25) can be suppressed, leading to increased measurement accuracy. The invention is particularly beneficial for building an oximeter (1) with improved precision. Further aspects of the invention concern features for improving the applicability of the apparatus (1) on curved surfaces (23) such as the strongly curved skulls of neonates.