Watch Terminal Biometric Sensing with Multi-Wavelength Light Spacing

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Solution Overview

Problem

Wearable mobile terminals face challenges in accurately measuring biometric signals due to their small size and frequent movement on the body, as well as the characteristics of the worn area, which affects the collection and measurement of biometric data.

Innovation Solution

A watch-type terminal with a sensing unit featuring light receiving sensors and light emitting devices spaced apart to accurately measure biometric signals, utilizing different wavelengths and intensities of light to account for skin color and depth, and incorporating light shielding barrier walls to prevent light leakage and improve signal accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the terminal size is reduced for wearable purposes, then portability and comfort are improved, but the accuracy of biometric signal measurement deteriorates

Engineering Contradiction:
Improveterminal sizeVSAvoidbiometric signal measurement accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent positions light emitting devices and light receiving sensors at specific distances from each other in the spatial dimension, creating an optical path that enables accurate biometric measurement despite the compact terminal size. This spatial arrangement allows the system to maintain measurement precision while occupying minimal volume on the user's body.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent utilizes different wavelengths of light (e.g., green light at 560-577nm) and adjusts light intensity parameters to optimize penetration depth and absorption characteristics. By changing these optical parameters, the system can accurately measure biometric signals through varying tissue depths while maintaining a compact device form factor.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multiple light emitting devices with different wavelengths are used to account for skin color and depth, then measurement accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvebiometric signal measurement accuracyVSAvoidsensing unit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the sensing function into separate components: multiple light emitting devices with different wavelengths positioned at specific locations, and corresponding light receiving sensors. This segmentation allows each component to be optimized independently while working together to provide comprehensive biometric measurement capability that accounts for skin color and depth variations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent positions light emitting devices and sensors at specific local locations on the terminal body, with different devices emitting different wavelengths at different positions. This local quality differentiation enables the system to target specific tissue depths and account for variations in skin characteristics without requiring the entire device to be complex.

Inventive Principle:
Principle #3Local quality

3Volume of moving object

If light emitting devices and sensors are positioned close together to minimize terminal size, then compactness is improved, but light leakage and signal interference increase

Engineering Contradiction:
Improveterminal sizeVSAvoidlight leakage
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and isolates light paths by positioning light emitting devices and light receiving sensors at specific distances from each other, creating distinct optical channels. This separation prevents light from one device from interfering with another device's sensor, eliminating light leakage issues while maintaining compact overall dimensions through optimized spatial arrangement.

Inventive Principle:
Principle #2Taking out (Extraction)

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 enables accurate measurement of biometric signals, including heart rate and oxygen saturation, regardless of skin color or thickness, by optimizing light output and reception, thus enhancing the reliability of biometric data collection on wearable devices.

Implementation Method 1

a first light emitting device and a second light emitting device which are spaced apart from each other by a specific distance

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Implementation Method 2

utilizing different wavelengths and intensities of light to account for skin color and depth

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 3

a light receiving sensor and light emitting devices spaced apart from each other by a specific distance for measuring an accurate biometric signal

Methodology Applied
Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentEP3238615B1Watch type terminal and method for controlling the same
Publication Date: 2023.07.19 LG ELECTRONICS INC
  • EP3238615B1 patent drawingFigure 1A
  • EP3238615B1 patent drawingFigure 1B~1C
  • EP3238615B1 patent drawingFigure 2A~2B

AI summary

The present invention relates to a watch type terminal, including a main body, and a sensing unit disposed on one surface of the main body and configured to acquire a biometric signal, wherein the sensing unit includes at least one green light emitting device provided on one surface of the main body and configured to output green light, at least one yellow light emitting device disposed with being spaced apart from the at least one green light emitting device, and configured to output yellow light with a different skin transmittance from that of the green light, a light receiving sensor surrounded by the green light emitting device and the yellow light emitting device, and configured to receive reflected green light and/or yellow light, and a controller configured to generate a biometric signal using light incident on the light receiving sensor.