Sensor Element Window with Fiber Optic Faceplate

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Solution Overview

Problem

Optical sensors, such as PPG sensors, face internal light pollution due to direct light rays from the light source traversing through the glass window and reaching the light detector, which affects measurement accuracy and visual aesthetics.

Innovation Solution

A window element comprising a plurality of adjacent optical fibers with a tinted medium between them, which reduces internal light pollution and allows for camouflage by matching the color of the surrounding apparatus, thereby minimizing the visibility of the sensor components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a glass window is used to seal the optical sensor, then protection against dust and moisture is improved, but internal light pollution increases due to direct light rays reaching the detector

Engineering Contradiction:
Improveprotection against dust and moistureVSAvoidinternal light pollution
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The window element is segmented into multiple adjacent optical fibers instead of using a continuous glass window. This segmentation allows the light to be transmitted through discrete fiber paths, preventing direct light rays from reaching the detector and reducing internal light pollution while maintaining protective sealing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A tinted medium is introduced as an intermediary substance between the optical fibers. This medium absorbs or filters direct light rays that would otherwise cause internal light pollution, while allowing the optical fibers to continue functioning as light transmission paths.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If traditional sealing methods are used, then protection is achieved, but visual aesthetics deteriorate due to visible sensor components

Engineering Contradiction:
ImproveprotectionVSAvoidvisual aesthetics
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The medium between the optical fibers is tinted with a specific color that matches or blends with the surrounding apparatus housing. This color matching camouflages the window element and underlying sensor components, improving visual aesthetics while maintaining the protective function.

Inventive Principle:
Principle #32Color changes

3Object-generated harmful factors

If light shielding units are added around the sensor components, then internal light pollution is reduced, but device complexity increases

Engineering Contradiction:
Improveinternal light pollutionVSAvoidstructure complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The window element combines multiple functions into a single integrated structure: it serves as the protective seal, the light transmission window, and the aesthetic cover. The tinted medium between the optical fibers simultaneously provides light pollution reduction and visual camouflage, eliminating the need for separate light shielding units.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The window element made of adjacent optical fibers with tinted medium performs multiple functions: sealing protection against dust and moisture, optical transmission for sensing, internal light pollution reduction, and aesthetic camouflage. This multi-functionality reduces overall device complexity by consolidating what would otherwise require multiple separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 use of a fiber optic faceplate with a tinted medium between optical fibers effectively reduces internal light pollution by more than 40% and enhances the visual appearance by hiding the sensor components, improving measurement accuracy and user experience.

Implementation Method 1

A window element comprising a plurality of adjacent optical fibers

Methodology Applied
Scientific EffectOptical fiber transmission: Optical Fibre

Implementation Method 2

a tinted medium between them, which reduces internal light pollution

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP3162285B1A sensor element
Publication Date: 2021.12.08 NOKIA TECHNOLOGIES OY
  • EP3162285B1 patent drawingFigure 1~3
  • EP3162285B1 patent drawingFigure 4A~6
  • EP3162285B1 patent drawingFigure 7~9

AI summary

A sensor element comprising: a light source configured to emit light to the exterior of the sensor element, a light detector configured to detect light that enters the sensor element, and a window element that covers at least one of the light source and the light detector, wherein the window element comprises a plurality of adjacent optical fibers.