Organic Light Emitting Diodes as Wavelength Discriminating Photodetectors
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Solution Overview
Problem
Pulse oximeters often rely on specific light sources that transmit light at limited wavelengths, excluding the use of less costly broadband emitters due to the need for binning LEDs to perform at specific frequencies, which limits their availability and increases costs.
Innovation Solution
The use of broadband emitters that emit light across a range of wavelengths, combined with wavelength discriminating detectors that selectively detect specific wavelengths based on physical characteristics, such as doped organic material, allowing for the calculation of physiological parameters without initial demodulation of signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If specific wavelength light sources are used in pulse oximeters, then measurement precision for physiological parameters is improved, but device complexity and cost increase due to the need for multiple specialized LEDs and binning processes
Solution Approach 1:
The patent segments the wavelength discrimination function from the light source to the detector. Instead of requiring multiple specialized LEDs, a single broadband emitter illuminates the tissue, and the detector is divided into multiple photodetector elements with different spectral sensitivities. Each photodetector element detects specific wavelength ranges by measuring light absorption at different wavelengths, enabling precise physiological parameter measurement while simplifying the light source configuration.
Solution Approach 2:
The patent makes the broadband emitter universal by using it for all wavelength-related measurements. A single light source covering a broad spectrum replaces multiple specialized wavelength sources, allowing the same emitter to provide all necessary wavelengths for measuring different physiological parameters simultaneously. This multi-functional approach reduces device complexity while maintaining measurement precision through the detector's spectral discrimination capability.
2Adaptability or versatility
If multiple specialized light sources are used to cover different wavelengths, then adaptability for measuring various physiological parameters is improved, but manufacturing cost increases due to binning requirements
Solution Approach 1:
The patent inverts the traditional approach by making the detector rather than the light source wavelength-specific. Instead of using multiple specialized LEDs with different spectral outputs, a single broadband emitter provides all wavelengths, and the detector elements are designed with different spectral sensitivities. This inversion eliminates the need for complex LED binning and selection processes, simplifying manufacturing while maintaining adaptability for measuring various physiological parameters.
Solution Approach 2:
The patent changes the spectral sensitivity parameter of the detector elements rather than changing the light source parameters. By creating photodetector elements with different spectral response characteristics, the system achieves wavelength discrimination without requiring multiple specialized light sources. This parameter change in the detector domain simplifies manufacturing processes while preserving the ability to measure multiple physiological parameters.
3Ease of manufacture
If broadband emitters are used instead of specialized light sources, then ease of manufacture and cost are improved, but measurement precision may be compromised without wavelength discrimination
Solution Approach 1:
The patent introduces the detector with multiple photodetector elements as an intermediary that performs wavelength discrimination. The broadband emitter provides all necessary wavelengths, and the detector elements act as intermediaries that selectively measure absorption at different wavelengths based on their spectral sensitivities. This intermediary detector resolves the apparent contradiction by enabling precise wavelength-specific measurements while allowing the use of simple broadband light sources.
Solution Approach 2:
The patent replaces the mechanical/optical system of multiple specialized LEDs with an electrical/electronic detection system. Instead of using multiple light sources with different spectral characteristics, a single broadband emitter is used with detector elements that electronically distinguish wavelengths through their different spectral responses. This substitution simplifies the light source system while maintaining measurement precision through the detector's spectral discrimination capability.
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 enables the use of a single broadband emitter and multiple detectors to measure various physiological parameters simultaneously, reducing the need for demodulation and increasing the availability of LEDs, thus lowering costs and enhancing monitoring capabilities.
Implementation Method 1
a sensor that includes a reverse biased organic light emitting diode (OLED) operating as a photodetector
Implementation Method 2
broadband emitters that emit light across a range of wavelengths
Implementation Method 3
wavelength discriminating detectors that selectively detect specific wavelengths based on physical characteristics, such as doped organic material
Data Source
AI summary
A system and method for determining physiological parameters of a patient based on light transmitted through the patient. The light may be transmitted via a broadband light source and received by a detector. The light may be selectively detected at a detector. Based on material characteristic of the detector, specific wavelengths of light are detected by the detector for use in monitoring the physiological parameters of the patient.