Capacitive Window Sensor Layout With Permittivity Compensation Electrode

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Solution Overview

Problem

Capacitive sensors used in vehicles and buildings, such as rain sensors, face interference from substrate dielectric conductivity and temperature, requiring complex compensation methods that increase costs and effort.

Innovation Solution

Incorporating an additional electrode to create a material property compensation electrical field that directly influences the sensor substrate, allowing for inherent compensation of conductivity and temperature effects, reducing the need for subsequent arithmetic compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex additional measurement and processing equipment is implemented to compensate for interference, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improvesensor signal reliabilityVSAvoiddetection setup complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a compensation electrode as an intermediary element that generates a counteracting electric field to neutralize the interference caused by substrate permittivity changes. This mediator approach allows compensation without complex computational processing, directly addressing the measurement precision issue while avoiding increased device complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The compensation electrode is configured to generate an electric field that preemptively counteracts the interference from substrate permittivity changes before they affect the measurement signal. By applying preliminary anti-action, the system maintains measurement precision without requiring complex post-processing equipment.

Inventive Principle:

Principle #9Preliminary anti-action

2Measurement precision

If complex additional measurement and processing equipment is implemented to compensate for interference, then measurement precision is improved, but manufacturing costs increase

Engineering Contradiction:

Improvesensor signal reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The compensation electrode serves as a simple intermediary component that can be manufactured and integrated into the sensor assembly using standard fabrication processes. This approach achieves measurement precision improvement without the high costs associated with complex additional measurement and processing equipment.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If computational compensation methods are used, then measurement precision is improved, but manufacturing effort increases

Engineering Contradiction:

Improvecompensation accuracyVSAvoidmanufacturing effort

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces computational compensation methods with a physical field-based compensation mechanism. The compensation electrode generates an electric field that physically counteracts interference, eliminating the need for complex arithmetic processing and reducing manufacturing effort associated with implementing and calibrating computational systems.

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

This approach provides more precise results with less manufacturing effort and cost, improving the accuracy and efficiency of capacitive sensor measurements.

Implementation Method 1

a first sensor section (7a) and a second sensor section (7b) which are arranged between a first surface (5a) of the polymer film (5) and the inner surface of the adjacent glass pane (3a), and a material property compensation electrode (9) which is arranged on the inner surface of the second glass pane (3b), adjacent to the second surface (5b) of the polymer film (5)

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

capacitive sensors, widely used especially as so-called 'rain sensors' (or touch sensors), function by generating an electric field between two electrodes spaced apart on a substrate and influencing this field with the physical quantity being measured

Methodology Applied

Scientific EffectElectric Field: Electric Field

Implementation Method 3

the measurement signal of such sensors is highly dependent on the permittivity (dielectric conductivity) of the substrate, which in turn exhibits a marked temperature dependence

Methodology Applied

Scientific EffectDielectric Permittivity: Dielectric Permittivity

Data Source

PatentEP3847060B1Detection system for the capacitive detection of a physical quantity on the inside and/or outside of a vehicle or building window or in its immediate vicinity

Publication Date: 2025.01.29 SAINT GOBAIN SEKURIT FRANCE

Figure 1~2
Figure 3

AI summary

The invention relates to a glazing unit of a vehicle or a building, comprising at least one glass pane or polymer film, wherein a capacitive sensor is arranged on a first surface of the or a glass pane or polymer film, said sensor comprising a first sensor section and a second sensor section located at a distance from the first sensor section on the first surface and acting as a signal read-out section, wherein, during the operation of the sensor, an electrical field is created between the first and second sensor sections, which partially penetrates the glass pane or polymer film, wherein a material property compensation electrode is applied to the second surface of the same glass pane or polymer film, opposite the second sensor section.