Polarized Optoelectronic Sensor Layout for Low Optical Crosstalk
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Solution Overview
Problem
Existing optoelectronic sensors in wearable devices face challenges in achieving a compact design with high sensitivity for measuring vital parameters, as they often suffer from optical crosstalk and signal interference.
Innovation Solution
The optoelectronic sensor incorporates a radiation-emitting and radiation-detecting semiconductor region with perpendicular polarization filters, a common carrier, and a plastic molding compound to minimize crosstalk, ensuring the radiation-emitting and detecting regions are arranged closely and shielded from each other, enhancing sensitivity and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the radiation-emitting and radiation-detecting semiconductor regions are arranged closely to achieve compact design, then the device size is reduced, but optical crosstalk increases and sensitivity deteriorates
Solution Approach 1:
A polarization filter is introduced as an intermediary element between the radiation-emitting and radiation-detecting semiconductor regions. This filter selectively transmits radiation with a specific polarization direction while blocking other directions, thereby reducing optical crosstalk between the closely arranged regions and maintaining high sensitivity despite the compact configuration.
2Device complexity
If polarization filters are arranged directly on the semiconductor regions, then the sensor structure becomes more compact, but manufacturing complexity increases
Solution Approach 1:
The polarization filter is merged with the semiconductor regions by arranging it directly on the radiation-emitting region and the radiation-detecting region, integrating multiple functions into a single compact structure. This combining approach reduces the overall device complexity while the standardized integration process manages manufacturing complexity.
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 configuration significantly reduces optical crosstalk, improves signal-to-noise ratio, and allows for a compact, high-sensitivity design suitable for wearable devices like sports watches, enabling accurate measurement of vital parameters such as heart rate and blood pressure.
Implementation Method 1
The first polarization filter comprises a first polarization direction and the second polarization filter comprises a second polarization direction. Here, the first polarization direction is different from the second polarization direction, in particular, the first polarization direction and the second polarization direction are perpendicular to each other.
Implementation Method 2
The emitted radiation may be at least partially absorbed and/or reflected by a body region, such as tissue or blood vessels.
Data Source
AI summary
In an embodiment an optoelectronic sensor includes a radiation-emitting semiconductor region, a radiation-detecting semiconductor region, a first polarization filter arranged above the radiation-emitting semiconductor region and including a first polarization direction and a second polarization filter arranged above the radiation-detecting semiconductor region and including a second polarization direction, wherein the first polarization direction and the second polarization direction are perpendicular to each other, wherein a radiation-reflecting or radiation-absorbing layer is arranged on side flanks of the radiation-emitting semiconductor region and/or the radiation-detecting semiconductor region and/or the first polarization filter and/or the second polarization filter.