Keyboard Guard Structures for Contaminant Ingress Prevention

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Electronic devices, particularly keyboards, are vulnerable to ingress of contaminants such as dust and liquid, which can damage electronics and hinder key movement by blocking electrical contacts.

Innovation Solution

Incorporation of mechanisms such as membranes, gaskets, brushes, wipers, flaps, funnels, skirts, elastomer bands, and bellows to prevent or alleviate contaminant ingress, including structures that block gaps, direct contaminants away, or use forced gas to expel them from the keyboard.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If membranes or gaskets are used to block contaminant ingress, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvekeyboard reliabilityVSAvoidkeyboard structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs flexible membranes and gaskets as thin film barriers to prevent contaminant ingress into the keyboard. These flexible protective layers conform to the keyboard structure while blocking dust and liquid, resolving the contradiction by providing reliable protection through simple thin film implementation rather than complex multi-component systems

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent introduces intermediate protective structures such as skirts and guard structures that act as mediators between the key caps and the underlying electronics. These intermediary elements block contaminant pathways without requiring direct modification of the electronics or key caps, thus improving reliability while adding minimal structural complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If guard structures are added to block gaps around key caps, then contaminant ingress is prevented, but ease of operation deteriorates

Engineering Contradiction:
Improvecontaminant ingressVSAvoidkey movement
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent employs dynamic guard structures such as flexible skirts that move with the key caps during operation. These structures maintain their blocking function against contaminants while dynamically adapting to key movement, thus preventing contaminant ingress without impeding ease of operation. The flexibility allows the guard structures to clear the path for key actuation while maintaining protection during static periods

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The guard structures are designed to automatically adjust and maintain their protective function without external intervention. The skirts and flaps self-adjust during key movement to maintain optimal positioning for both protection and operation, eliminating the need for additional control mechanisms that would complicate the system or hinder user interaction

Inventive Principle:
Principle #25Self-service

3Object-affected harmful factors

If bellows are used to blast contaminants with forced gas, then contaminant removal is improved, but use of energy increases

Engineering Contradiction:
Improvecontaminant presenceVSAvoidenergy for contaminant expulsion
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic or on-demand bellows activation rather than continuous operation. The forced gas expulsion is triggered only when contaminant ingress is detected or at scheduled intervals, significantly reducing energy consumption while maintaining effective contaminant removal capability when needed

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent explores replacing active mechanical bellows systems with passive or semi-passive alternative mechanisms such as spring-loaded ejectors or gravity-assisted contaminant collection systems. These substitutions reduce or eliminate the need for continuous energy input while maintaining contaminant removal functionality

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

Effectively prevents and alleviates contaminant ingress, maintaining keyboard functionality and reducing damage to electronic components while minimizing interference with key movement.

Implementation Method 1

the elastomer band is operable to force contaminants into a cavity defined in the foundation using gas forced from the vent

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

the skirt is an elastomer

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3420432B1Ingress prevention for keyboards
Publication Date: 2025.07.02 APPLE INC
  • EP3420432B1 patent drawingFigure 1
  • EP3420432B1 patent drawingFigure 2
  • EP3420432B1 patent drawingFigure 3A~3C

AI summary

Keyboards include mechanisms that prevent and/or alleviate contaminant ingress. In some embodiments, a keyboard assembly includes a substrate, a key cap, a movement mechanism moveably coupling the key cap to the substrate, and a guard structure coupled to the key cap operable to direct contaminants away from the movement mechanism. In other embodiments, a keyboard includes a base; a web that defines apertures; keys moveably coupled to the base within the apertures; and a gasket coupled to the keys, the gasket fixed between the web and the base, operable to block passage of contaminants into the apertures.