Optical Sensor Layout With Vertically Offset Emitter and Receiver

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Solution Overview

Problem

Non-invasive optical sensing devices face instability and inaccuracy in detecting physiological signals due to changes in the relative position and distance between the device and the skin, especially during physical activity, leading to fluctuations in the returned measuring light.

Innovation Solution

The optical sensing device incorporates a light-receiving device made of group III-V semiconductor material with a large external quantum efficiency, positioned to receive light with a specific wavelength, and is designed with a carrier body and light-emitting devices to minimize crosstalk and enhance accuracy by optimizing the distance and area for improved signal-to-noise ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the light-receiving device has a larger area to capture more light, then the signal-to-noise ratio improves, but the device size and complexity increase

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoiddevice structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating a localized light-trapping structure around the light-receiving device using block walls with light-absorbing materials. This concentrates the light collection function in a specific region rather than requiring a uniformly large area, thereby improving the signal-to-noise ratio without proportionally increasing the overall device footprint and complexity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The light-receiving device is nested within a cavity formed by block walls that extend from the carrier body. This nested structure allows the light-receiving device to be surrounded by light-trapping elements, effectively increasing the light collection efficiency and signal-to-noise ratio while maintaining a compact overall device structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Measurement precision

If the distance between the light-emitting device and skin is reduced to improve signal strength, then the measurement accuracy improves, but the device becomes more sensitive to position changes during movement

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidstability during movement

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent implements beforehand cushioning by positioning the light-receiving device closer to the skin surface than the light-emitting device, and surrounding it with light-absorbing block walls. This pre-arranged configuration creates a more stable light reception environment that compensates for position changes during movement, maintaining measurement reliability while achieving high measurement accuracy through optimized light reception.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Use of energy by moving object

If the light-receiving device is positioned closer to the skin to reduce distance effects, then the signal strength increases, but the device structure becomes more complex

Engineering Contradiction:

Improvesignal strengthVSAvoidcarrier body structure

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent segments the device structure by separating the light-emitting and light-receiving functions into different spatial zones. The light-receiving device is positioned in a dedicated cavity closer to the skin, while the light-emitting device occupies a separate region. This segmentation allows optimized signal reception without requiring the entire device to be reconfigured, thereby increasing signal strength while maintaining manageable structural complexity.

Inventive Principle:

Principle #1Segmentation

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 enhances the detection limit and signal-to-noise ratio, resulting in more stable and accurate measurement of physiological signals such as heart rhythm, blood oxygen level, and blood pressure, even during physical activity.

Implementation Method 1

With the properties of light absorption, light scattering, and light reflection, the optical sensing device can receive a portion of the returned measuring light

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a light-receiving device including a group III-V semiconductor material disposed on the carrier body, wherein the light-receiving device is capable of receiving a first received wavelength having a largest external quantum efficiency

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS11894481B2Optical sensing device and optical sensing system thereof comprising light emitting device and light receiving device completely sandwiched by the topmost surface and bottommost surface of a carrier body with different vertically separated distances

Publication Date: 2024.02.06 ENNOSTAR CORP

AI summary

This disclosure discloses an optical sensing device. The device includes a carrier body having a topmost surface; a first light-emitting device disposed on the carrier body and having a light-emitting surface; and a light-receiving device comprising a group III-V semiconductor material disposed on the carrier body and having a light-receiving surface. The light-emitting surface is separated from the topmost surface by first distant H1, the light-receiving surface is separated from the topmost surface by a second distance H2, and H1 is different from H2.