Optical Sensor Compensation Element for Fluid Volume Changes

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Solution Overview

Problem

Optical sensor devices used to detect fluid substances in vehicles are prone to damage due to increases in volume or pressure, leading to errors in detection, especially when the fluid freezes, causing mechanical stress and deformation of the sensor's surfaces.

Innovation Solution

An optical sensor device with a deformable compensation element made of elastomeric material is integrated to absorb volume increases, maintaining the sensor's geometrical integrity and preventing mechanical stress on the detection portion, ensuring accurate detection by maintaining the critical angle of total reflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the optical sensor device uses a rigid structure to maintain detection precision, then measurement precision is improved, but the device becomes vulnerable to damage from volume increases or pressure changes

Engineering Contradiction:
Improvedetection precisionVSAvoiddevice reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The device is divided into a rigid detection portion (prism and receiver) for maintaining optical precision and a separate flexible compensation element (membrane) for absorbing volume changes. This segmentation allows each part to perform its specialized function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flexible compensation element acts as an intermediary between the fluid substance and the rigid detection portion. It absorbs the mechanical stress from volume increases or pressure changes before they can reach and damage the sensitive optical components, thereby protecting the detection precision while ensuring device reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the optical sensor device uses a flexible structure to accommodate volume changes, then device reliability is improved, but measurement precision deteriorates due to surface deformation

Engineering Contradiction:
Improvedevice reliabilityVSAvoiddetection precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The device separates the flexible compensation function (membrane) from the rigid detection function (prism and optical surfaces). The membrane handles volume changes while the prism maintains its precise geometric configuration, ensuring that flexibility does not compromise measurement precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The compensation element serves as a protective intermediary that isolates the rigid detection portion from mechanical stresses. By absorbing volume changes before they reach the optical surfaces, it prevents deformation while allowing the detection portion to maintain its precise geometry for accurate measurements.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the optical sensor device protects sensitive components from direct contact with the fluid, then device reliability is improved, but the ability to detect fluid characteristics accurately is reduced

Engineering Contradiction:
Improvedevice reliabilityVSAvoiddetection precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The membrane acts as an intermediary that transmits mechanical information (volume changes, pressure) to the detection portion without requiring direct contact between the fluid and sensitive components. This allows the fluid to be contained while still enabling accurate detection of its physical characteristics through the membrane's deformation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The device replaces direct mechanical contact between the fluid and optical components with an indirect mechanical coupling through the membrane. The membrane translates fluid volume and pressure changes into mechanical deformations that can be detected optically, maintaining reliability while preserving detection precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 deformable compensation element effectively prevents damage and maintains detection accuracy by absorbing volume increases, ensuring the sensor operates correctly even under conditions of freezing or pressure changes, reducing the risk of mechanical stress and deformation.

Implementation Method 1

At the interface with the fluid substance, a part of the radiation is refracted into the substance

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

a part is reflected, where the latter part is detected by the receiver

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

a protection arrangement, in particular comprising at least one compensation element (13), which has a body at least in part elastically deformable or yieldable

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3775846B1Optical sensor device for fluid substances
Publication Date: 2024.11.13 ELTEK SPA
  • EP3775846B1 patent drawingFigure 1
  • EP3775846B1 patent drawingFigure 2
  • EP3775846B1 patent drawingFigure 3

AI summary

An optical sensor device (1) for a fluid substance (LS) comprises a device body (2) having a detection portion (14), associated to which is a sensitive optical part that comprises at least one of an emitter (20) and a receiver (21) of an optical radiation (Re, Rr). The detection portion (14) is made of a material transparent to the optical radiation (Re, Rr) and has an inner surface (23 a, 23b) and an outer surface (15), the outer surface (15) being designed to be in contact with the fluid substance (LS) and the inner surface (23a, 23b) being designed to be isolated from the fluid substance. The at least one of the emitter (20) and the receiver (21) of the sensitive optical part is optically coupled to the inner surface (23a, 23b) of the detection portion (14), in such a way that the optical radiation (Re, Rr) is at least in part propagated through the detection portion (14), in particular with an angle and/or an intensity that is variable as a function of a characteristic of the fluid substance. The optical sensor device (1) comprises a protection arrangement, configured for preventing possible deformation of the detection portion (14) caused by an increase in volume of the fluid substance (LS), in particular deformation of at least one of its inner surface (23a, 23b) and its outer surface (15). The protection arrangement comprises at least one compensation element (13) having an elastically deformable body, which is able to contract, for compensating thereby a possible increase in volume of the fluid substance (LS) or else for enabling a reversible displacement of the detection portion (14) following upon a possible increase in volume of the fluid substance (LS).