Capacitive Coffee Machine Control Panel for Dirt-Resistant Input

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Solution Overview

Problem

Current automatic coffee machines with electro-mechanical switches face issues such as reduced reliability due to dirt interference, lengthy assembly times, limited design aesthetics, and increased risk of damage from excessive pressure.

Innovation Solution

The use of capacitive sensors in the control panel, which are more reliable, durable, and easier to assemble, with a flexible support structure that ensures proper contact and simplified component assembly, allowing for a more attractive and functional user interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electro-mechanical switches are used in the control panel, then the machine can generate control signals, but the reliability decreases in the presence of dirt and atmospheric variations

Engineering Contradiction:
Improvecontrol panel reliabilityVSAvoiddirt interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces electro-mechanical switches with capacitive sensors, eliminating moving mechanical parts that are susceptible to dirt accumulation. The capacitive sensing mechanism detects user input through electrical field changes rather than mechanical contact, making it immune to dirt interference and atmospheric variations while maintaining reliable control signal generation.

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

Solution Approach 2:

The patent introduces a dielectric layer as an intermediary between the capacitive sensor electrode and the user's finger. This dielectric layer protects the sensing mechanism from direct contact with contaminants while still allowing capacitive coupling to occur, enabling reliable detection through the intermediary barrier.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If electro-mechanical switches are used in the control panel, then control functions can be implemented, but the assembly time increases due to large number of components

Engineering Contradiction:
Improveassembly timeVSAvoidnumber of components
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges multiple discrete electro-mechanical switch components into a single integrated capacitive sensor array. Instead of assembling numerous individual switches, the control panel uses a unified capacitive sensing layer with multiple detection zones, dramatically reducing component count and assembly time while maintaining full control functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The capacitive sensor structure serves multiple functions simultaneously: it provides tactile feedback, detects multiple input zones, generates control signals, and requires minimal assembly steps. This multi-functional design eliminates the need for separate components that would otherwise be required for each switching function.

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

3Adaptability or versatility

If electro-mechanical switches are used in the control panel, then button press detection is possible, but the design flexibility for control panel shape is limited

Engineering Contradiction:
Improvecontrol panel shape designVSAvoidcontrol panel geometry
Core Design Contradiction:
Adaptability or versatilityVSShape

Solution Approach 1:

The patent employs a flexible capacitive sensor layer that can be conformally deposited onto control panels of various shapes and geometries. Unlike rigid electro-mechanical switches that require specific mounting configurations, the thin-film capacitive structure adapts to curved, irregular, or complex panel shapes, providing unlimited design flexibility while maintaining sensing functionality.

Inventive Principle:
Principle #30Flexible shells and thin films

4Ease of operation

If excessive pressure is applied to electro-mechanical switches, then button activation can be achieved in dirty conditions, but the switch may be damaged

Engineering Contradiction:
Improvebutton activationVSAvoidswitch durability
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent replaces the mechanical switch mechanism with a capacitive sensing system that detects button presses through electrical field changes rather than requiring physical contact or force application. This eliminates the risk of mechanical damage from excessive pressure while maintaining ease of operation, as users can activate controls with light touches without risking component failure.

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 capacitive sensor-based control panel provides enhanced durability, ease of use, and faster assembly, while maintaining reliability even in dirty conditions, offering improved design flexibility and reduced risk of mechanical failure.

Implementation Method 1

capacitive sensors which are more reliable, durable, and easier to assemble

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2111779B1Automatic coffee machine having a control panel
Publication Date: 2010.05.19 DE LONGHI SPA
  • EP2111779B1 patent drawingFigure 1
  • EP2111779B1 patent drawingFigure 2
  • EP2111779B1 patent drawingFigure 3

AI summary

The automatic coffee machine (1) has a control panel (2) with a user interface comprising a plurality of capacitive sensors (4) for generating control and/or programming signals of the machine (1), the interface comprising a shield (5) overlapped on a flexible support (6) for the capacitive sensors (4), the shield (5) having specific detection zones (7) marked by signs (8) for identifying a programme and/or control function, each of the detection zones (7) being overlapped onto an electrode (9) of a corresponding one of the capacitive sensors (4), the flexible support (6) presenting the electrode (9) for the capacitive sensors (4) and electrically conductive tracks (10) having terminal contacts (11) connected to a connector (12) of printed circuit board (3) of management of the machine (1).