Venous Network Sensor Waveguide Extraction Zones

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Solution Overview

Problem

Venous network sensors face issues with overexposure and artefacts due to direct infrared rays striking the image acquisition means, leading to poor image quality, especially when capturing on the fly.

Innovation Solution

A sensor design incorporating a waveguide with extraction zones oriented to avoid intercepting the sensitive element, using microprisms or inclined facets to divert infrared rays, and a control method to adjust illumination power based on the presence of a living body, preventing saturation and enhancing image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If infrared emitters are positioned along rows and columns to illuminate the image acquisition means, then the venous network can be captured, but direct rays cause overexposure and artefacts on the acquired image

Engineering Contradiction:

Improveimage qualityVSAvoidoverexposure and artefacts

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

A waveguide is introduced as an intermediary component between the infrared illumination source and the image acquisition means. The waveguide channels infrared rays through its structure and extracts them at specific zones, preventing direct rays from reaching the sensitive element while still providing necessary illumination for venous network capture.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The waveguide features localized extraction zones with specific extraction faces oriented at particular angles. These extraction zones are strategically positioned to provide infrared illumination to the venous network while directing extracted rays away from the sensitive element, creating local quality variations in ray distribution.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If the extraction zones are oriented to extract infrared rays from the waveguide, then direct rays are prevented from reaching the sensitive element, but the extraction geometry must be precisely controlled

Engineering Contradiction:

Improvedirect ray interceptionVSAvoidextraction zone geometry

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The extraction zones are defined by specific geometric parameters including extraction face angles (e.g., 45 degrees), positions, and orientations. By controlling these parameters, the waveguide directs infrared rays at specific angles away from the sensitive element while maintaining effective illumination of the venous network.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If the sensor captures images on the fly without constraining object position, then ease of operation is improved, but artefacts increase due to varying direct ray exposure

Engineering Contradiction:

Improveobject position constraintVSAvoidimage quality

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The waveguide acts as a mediator that decouples the illumination geometry from the image acquisition geometry. This allows the system to capture images without constraining object position while the waveguide's extraction zones consistently direct rays away from the sensitive element, maintaining image quality regardless of object placement.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 effectively reduces artefacts and improves image quality by ensuring that infrared rays are directed away from the sensitive element, allowing for accurate venous network capture without overexposure, even when the body is present.

Implementation Method 1

a waveguide illuminated by said infrared illumination source and having at least one extraction zone intended to extract the infrared rays from said waveguide through an extraction face of the waveguide

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

the or each extraction zone is such that the or each main extraction direction is oriented so as not to intercept said sensitive element

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 3

said or at least one of said extraction zones consists of an inclined facet produced in said extraction face

Methodology Applied

Scientific EffectGeometric optics reflection: Reflection

Data Source

PatentUS9052233B2Sensor for venous networks of a part of a living body

Publication Date: 2015.06.09 IDEMIA IDENTITY & SECURITY FRANCE SAS

AI summary

A sensor for venous networks of a part of a living body, havingan infrared illumination source,a waveguide illuminated by the infrared illumination source and having, on one face, at least one extraction zone intended to extract the infrared rays from the waveguide in at least one main extraction direction,an image acquisition means disposed opposite the one face so as to define between them a passage through the entrance of which the part of the living body can enter, and having a sensitive element,the or each extraction zone being such that the or each main extraction direction of the extraction zone oriented so as not to intercept the sensitive element.