Biological Sensor Module Convex Curved Surface Pulse Wave Detection

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Solution Overview

Problem

Existing pulse wave meters suffer from an unstable S/N ratio due to inefficient light collection and external noise interference, which affects the accuracy of pulse rate measurement.

Innovation Solution

A biological sensor module with a passage section featuring a first convex curved surface for applying pressure and a second convex curved surface with a smaller radius of curvature to collect reflected light into a spot on the light receiver, enhancing light collection and reducing noise interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a curved surface of the lens presses the subject's finger to apply predetermined pressure, then the pulse wave signal strength is improved, but the light collection efficiency deteriorates due to unstable contact and noise light mixing

Engineering Contradiction:

Improvepulse wave signal strengthVSAvoidlight collection efficiency

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The lens is divided into two distinct functional surfaces: a first curved surface for applying pressure to the finger and a second curved surface for collecting light. This segmentation allows each surface to be optimized for its specific function without compromising the other, resolving the contradiction between pressure application and light collection efficiency

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the lens are given different curvatures and functions. The first curved surface has properties optimized for mechanical pressure application, while the second curved surface has properties optimized for optical light collection. This local differentiation enables simultaneous achievement of both pressure application and reliable light collection

Inventive Principle:

Principle #3Local quality

2Reliability

If the lens is optimized to collect light into a spot on the PD, then the light collection efficiency is improved, but the pressure application capability deteriorates due to unstable contact

Engineering Contradiction:

Improvelight collection efficiencyVSAvoidpulse wave signal strength

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The lens employs curved surfaces with specific radii of curvature to achieve both mechanical and optical functions. The first curved surface applies pressure through its curvature, while the second curved surface collects light through its curvature, with the second radius being smaller than the first to optimize light focusing

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 solution increases the precision of pulse wave detection by improving the S/N ratio of the pulse signal, allowing for more accurate calculation of the pulse rate.

Implementation Method 1

The outer surface section has a first convex curved surface that presses the living body

Methodology Applied

Scientific EffectPressure: Pressure Increase

Implementation Method 2

the inner surface section has a second convex curved surface that collects the reflected light incident on the passage section into a spot on the light receiver

Methodology Applied

Scientific EffectLight refraction and focusing: Refraction

Data Source

PatentUS11419510B2Biological sensor module and biological information measuring apparatus

Publication Date: 2022.08.23 SEIKO EPSON CORP

AI summary

A biological sensor module includes a light emitter that emits irradiation light with which a living body is irradiated, a light receiver that receives reflected light that is the irradiation light reflected off the living body, and a passage section through which the irradiation light and the reflected light pass. The passage section includes an outer surface section that comes into contact with the living body and an inner surface section that is opposite the outer surface section. The outer surface section has a first convex curved surface that presses the living body, and the inner surface section has a second convex curved surface that collects the reflected light incident on the passage section into a spot on the light receiver.