Environmental Sensor Fouling Detection via Reflected Light

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Solution Overview

Problem

Environmental sensors exposed to their environment often accumulate fouling layers, which inhibit accurate parameter readings, and existing solutions do not effectively address this issue in the context of semiconductor-based sensors.

Innovation Solution

The integration of fouling layer detection capabilities into semiconductor-based environmental sensors, utilizing a common substrate for multiple sensors, including a light source and light detector, and employing frequency analysis of ambient and reflected light to differentiate and characterize fouling layers, with a semiconductor package design that simplifies packaging and allows for low-cost manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If environmental sensors are exposed to the environment for long-term operation, then they can monitor parameters continuously, but fouling layers accumulate on the sensor surface reducing measurement precision

Engineering Contradiction:
Improveoperational durationVSAvoidparameter reading accuracy
Core Design Contradiction:
Duration of action of stationary objectVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by implementing fouling layer detection before it significantly degrades sensor measurements. The system continuously monitors for fouling accumulation and triggers cleaning or calibration actions proactively, preventing measurement precision loss before it occurs during long-term operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where sensor measurements are continuously monitored for signs of fouling accumulation. The system uses feedback from measurement quality indicators to trigger appropriate responses such as cleaning cycles or calibration adjustments, maintaining measurement precision throughout extended operational periods.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If a separate light source and light detector are used for fouling detection, then detection accuracy is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvefouling detection accuracyVSAvoidsensor construction complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the light source and light detector into an integrated optical module that works in conjunction with the environmental sensor. This combination maintains sufficient fouling detection accuracy while reducing device complexity and manufacturing cost compared to fully separate components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements multi-functionality by designing the light source and detector to serve dual purposes: they detect fouling layers on the sensor surface while also enabling optical measurements for environmental parameter detection. This universal approach improves detection accuracy without proportionally increasing device complexity.

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

3Ease of manufacture

If traditional packaging is used for the sensor, then manufacturing is straightforward, but the packaging does not facilitate simplified construction or low-cost manufacturing when integrating multiple sensors

Engineering Contradiction:
Improvepackaging simplicityVSAvoidintegration capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent applies segmentation by dividing the sensor system into modular components including the environmental sensor, the optical module for fouling detection, and the processing unit. This segmented architecture allows each component to be manufactured separately using standard processes and then assembled, achieving both packaging simplicity and integration versatility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements nesting by placing the optical detection components within the sensor package structure, with the light source and detector positioned in relation to the sensor surface. This nested arrangement achieves space-efficient packaging that facilitates simplified construction while maintaining the adaptability to integrate multiple sensor functions.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

Enables reliable detection and characterization of fouling layers, ensuring accurate sensor readings and extending the operational life of environmental sensors in various applications, including building automation and automotive systems, by using a compact and cost-effective design.

Implementation Method 1

a light source operable to illuminate the surface, whereby at least some of the light from the light source is reflected by the surface onto the light sensor

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Implementation Method 2

at least some of the light from the light source is reflected by the surface onto the light sensor

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 3

a light sensor operable to detect ambient light passing through the surface and to detect reflected light from the surface

Methodology Applied
Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentEP2738544B1Fouling layer detection on an environmental sensor
Publication Date: 2016.09.28 NXP BV
  • EP2738544B1 patent drawingFigure 1~2
  • EP2738544B1 patent drawingFigure 3~4
  • EP2738544B1 patent drawingFigure 5~6

AI summary

An environmental sensor and a method of operating an environmental sensor are disclosed. The environmental sensor includes: a semiconductor substrate (20) including a light sensor (10), a surface (5) through which ambient light can pass to reach the light sensor, and a light source (15) operable to illuminate the surface, whereby at least some of the light from the light source is reflected by the surface onto the light sensor. The environmental sensor is operable to determine the presence of a fouling layer on the surface by comparing measurements of ambient light and reflected light by the at least one light sensor.