Finger Reflectance BAC Assay With Multi-Wavelength Stray Light Shielding
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Solution Overview
Problem
Existing methods for accurately and quickly determining a person's blood alcohol concentration (BAC) prior to driving are inadequate, contributing to traffic accidents due to alcohol abuse.
Innovation Solution
A rapid and accurate assayer (RACAS) that measures light reflectance from a person's finger at multiple wavelengths to determine BAC by analyzing the intensity of reflected light absorbed by finger tissue, using a contact substrate and sensors to process assay signals and calculate alcohol concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional BAC measurement methods are used, then measurement accuracy may be adequate, but measurement time is too long and cannot provide rapid results for pre-driving assessment
Solution Approach 1:
The patent segments the BAC measurement process into multiple wavelength-specific detection channels, each measuring light absorption at different wavelengths (e.g., 980nm for water, 1300nm for alcohol). By segmenting the measurement into parallel wavelength channels rather than sequential steps, the system achieves rapid multi-parameter detection simultaneously, resolving the contradiction between speed and accuracy.
Solution Approach 2:
The patent transitions from traditional single-wavelength or time-sequential measurement to multi-wavelength simultaneous measurement by adding the wavelength dimension. Multiple light sources operating at different wavelengths illuminate the tissue concurrently, and sensors detect reflected light across the wavelength spectrum simultaneously, enabling rapid BAC assessment without sacrificing measurement precision.
2Measurement precision
If multiple wavelengths are used to improve measurement accuracy, then BAC determination precision increases, but device complexity increases due to multiple light sources and sensors
Solution Approach 1:
The patent implements multi-functionality by designing a single assayer device that simultaneously performs multiple functions: it measures BAC, assesses tissue perfusion, and evaluates oxygenation status all through one integrated multi-wavelength light reflection system. This universal device replaces what would traditionally require multiple separate measurement tools, reducing overall system complexity while maintaining high measurement precision.
Solution Approach 2:
The patent merges multiple detection functions into a unified system where light sources at different wavelengths and corresponding sensors are integrated into a single device. By combining BAC measurement, perfusion assessment, and oxygenation monitoring into one merged apparatus rather than separate devices, the system achieves high precision without proportionally increasing complexity.
3Measurement precision
If light transmission through contact substrate is used to measure tissue absorption, then measurement accuracy improves, but the system becomes sensitive to contact pressure variations affecting light transmission
Solution Approach 1:
The patent incorporates feedback mechanisms where sensors detect variations in light reflection intensity caused by contact pressure changes. The system uses this feedback information to compensate for pressure-induced variations in transmission, maintaining measurement consistency. By monitoring and compensating for pressure effects in real-time, the system preserves both accuracy and reliability under varying contact conditions.
Solution Approach 2:
The patent uses a contact substrate as an intermediary element between the light sources/sensors and the tissue. This substrate serves as a mediator that standardizes the optical interface, reducing direct sensitivity to pressure variations. The substrate acts as a buffer that maintains consistent optical coupling while allowing natural tissue interaction, thereby improving both precision and reliability.
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
Provides a quick and precise measurement of BAC, reducing the risk of substance abuse-related traffic accidents by enabling effective pre-driving assessments.
Implementation Method 1
measuring reflectance of light from the person's finger at a plurality of different wavelengths
Implementation Method 2
The absorption is a function of molecular components of the finger tissue, such as by way of example water and hemoglobin, and alcohol present in the assay tissue that absorb and/or scatter the light
Implementation Method 3
The at least one sensor generates a signal, hereinafter also referred to as an assay signal, responsive to intensity of the reflected assay light that the at least one sensor receives
Data Source
AI summary
Apparatus for assaying blood alcohol concentration (BAC), the apparatus comprising: a housing for receiving a finger of a person; at least one light source that transmits light at at least one assay wavelength in respective directions so that the transmitted light from all the light sources converges to overlap in a same convergence region that illuminates an assay region of a finger received by the housing; a light sensor positioned to receive and generate an assay signal responsive to assay light reflected by tissue in the assay region; and a light shield that enables assay light from the convergence region to reach the light sensor and shields the light sensor from stray light that is not reflected by tissue in the assay region from assay light originating from the at least one light source.