InGaAs Photodiode Window Layer for Visible-NIR Sensing
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Solution Overview
Problem
Existing non-invasive sensors for measuring blood analytes require multiple detectors to cover a broad range of wavelengths, leading to increased size, complexity, and inaccuracies due to variations in optical radiation path length.
Innovation Solution
A single enhanced InGaAs photodiode with a window layer composed of InAlAs and a thin thickness is used, allowing it to detect optical radiation at both visible and near-infrared wavelengths, thereby reducing the need for multiple detectors and improving signal strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple detectors are used to cover a broad range of wavelengths, then the detection capability is improved, but the device size and complexity increase
Solution Approach 1:
The InGaAs photodiode is engineered to perform multiple detection functions across different wavelength ranges (visible and near-infrared) that traditionally required separate detectors. This multi-functional design allows a single device to cover the spectral range needed for various blood analyte measurements, eliminating the need for multiple specialized detectors and reducing overall system complexity
Solution Approach 2:
The patent combines the detection capabilities of what would traditionally require separate visible-range and near-infrared-range detectors into a single InGaAs photodiode device. By merging these functions into one integrated detector, the system achieves broad spectral coverage while reducing the number of components, simplifying the optical path, and minimizing alignment requirements
2Adaptability or versatility
If multiple detectors are used to cover a broad range of wavelengths, then the detection capability is improved, but the sensor size increases
Solution Approach 1:
The InGaAs photodiode serves multiple detection purposes across different wavelength ranges, allowing a single sensor component to replace what would traditionally require multiple separate detectors. This multi-functional approach maintains broad spectral detection capability while significantly reducing the overall sensor footprint and eliminating the space needed for multiple detector elements and their respective optical paths
3Adaptability or versatility
If multiple detectors are used, then the wavelength coverage is improved, but measurement accuracy decreases due to path length variations
Solution Approach 1:
The patent merges the detection function into a single InGaAs photodiode that handles both visible and near-infrared wavelengths. This unified detection approach ensures that all wavelength measurements are performed through the same optical path and detection mechanism, eliminating the path length variations and alignment discrepancies that would arise from using multiple separate detectors positioned at different locations
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
The enhanced photodiode enables a non-invasive sensor to detect a broader range of wavelengths with fewer detectors, resulting in a more compact design and improved signal strength, which enhances the accuracy of blood analyte measurements.
Implementation Method 1
the thickness of the window layer can be minimized or the bandgap of the window layer can be maximized, or both, to increase the transmittance of the window layer for certain wavelengths of optical radiation
Implementation Method 2
a photodiode is disclosed herein that can detect optical radiation at a broad range of wavelengths obviating the necessity for two separate photodiodes
Data Source
AI summary
Embodiments of the present disclosure include a photodiode that can detect optical radiation at a broad range of wavelengths. The photodiode can be used as a detector of a non-invasive sensor, which can be used for measuring physiological parameters of a monitored patient. The photodiode can be part of an integrated semiconductor structure that generates a detector signal responsive to optical radiation at both visible and infrared wavelengths incident on the photodiode. The photodiode can include a layer that forms part of an external surface of the photodiode, which is disposed to receive the optical radiation incident on the photodiode and pass the optical radiation to one or more other layers of the photodiode.