3D Grounding Element in Humidity Sensor Assembly for ESD Protection

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Solution Overview

Problem

Humidity sensor assemblies are vulnerable to uncontrolled electrostatic discharges (ESD) during circuit board processing, which can damage the components and the signal processing module, particularly when mounted on a circuit board.

Innovation Solution

A humidity sensor arrangement with a three-dimensional, electrically conductive grounding element in the form of a bonding element, designed with an approximately circular base and upward taper, is integrated in the encapsulation recess, connected to a ground contact area to divert discharge currents away from the signal processing module.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a humidity sensor assembly is mounted on a circuit board, then the sensor can perform humidity measurement, but uncontrolled electrostatic discharges can occur during processing that may damage the components and signal processing module

Engineering Contradiction:
Improveprotection against electrostatic dischargeVSAvoidelectrostatic discharge damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A bonding element serves as an intermediary discharge path between the encapsulation recess and ground. This mediator captures electrostatic discharge currents before they can reach sensitive components, providing protection without interfering with normal sensor operation. The bonding element is positioned to intercept discharge paths while maintaining electrical isolation from the measurement circuitry.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The bonding element is pre-positioned and connected to ground before any electrostatic discharge event can occur. This preliminary protective measure ensures that when ESD occurs, the discharge current is immediately diverted through the pre-established bonding element path, preventing damage to vulnerable components before they can be affected.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a discharge element is arranged in the recess area, then discharge currents can be dissipated, but the structural integrity and sealing of the encapsulation may be compromised

Engineering Contradiction:
Improvedischarge current dissipationVSAvoidencapsulation integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The bonding element extends in the vertical dimension from the encapsulation recess downward to the ground connection, creating a three-dimensional discharge path. This vertical arrangement allows the discharge element to function effectively without compromising the horizontal sealing integrity of the encapsulation recess, as the bonding element is positioned to intercept discharge currents while maintaining the encapsulation's protective barrier.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 prevents damage to the signal processing module by diverting discharge currents through the grounding element to ground, ensuring rapid voltage dissipation and protecting sensitive areas from capacitive coupling effects.

Implementation Method 1

uncontrolled electrostatic discharges (ESD) can occur during further processing of the board

Methodology Applied
Scientific EffectElectrostatic discharge: Electrostatic Discharge

Implementation Method 2

at least one electrically conductive grounding element is arranged in the area of the recess and is designed as a three-dimensional bonding element

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

a capacitive humidity sensor is mounted on which an integrated signal processing module is arranged

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 4

a dielectric measuring layer is arranged between the base electrode and the top electrode, which has a capacitance that depends on the humidity

Methodology Applied
Scientific EffectDielectric permittivity: Dielectric Permittivity

Implementation Method 5

The bonding element and a gas-permeable protective layer are arranged in the recess above the humidity sensor

Methodology Applied
Scientific EffectPermeation: Permeation

Data Source

PatentEP4215908B1Moisture sensor assembly
Publication Date: 2025.12.31 E E ELEKTRONIK GES
  • EP4215908B1 patent drawingFigure 1a~1c
  • EP4215908B1 patent drawingFigure 2~3
  • EP4215908B1 patent drawingFigure 4

AI summary

The present invention relates to a humidity sensor arrangement with an integrated signal processing module and at least one capacitive humidity sensor arranged on the signal processing module. An encapsulation partially surrounds the signal processing module and has a recess in the area of ​​the humidity sensor. Furthermore, at least one electrically conductive discharge element is provided, which is arranged in the area of ​​the recess. The discharge element is designed as a three-dimensional bonding element (Fig. 2).