Operating module for a domestic appliance

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Solution Overview

Problem

Existing control panels for household appliances, particularly hobs, suffer from diffuse edges and optical crosstalk, leading to imprecise and less detailed illumination of symbols, which is costly and difficult to produce with high precision.

Innovation Solution

An operating module with a carrier having a diffusion film and a symbol film with a touch-sensitive touch panel featuring a metal layer with cutouts, where the metal layer is electrically connected and the film is designed with a light-absorbing layer underneath, and a light-permeable blocking layer with windows to prevent optical crosstalk, allowing for precise and detailed illumination with a low overall height and cost-effective production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional illuminated control panels are used, then symbols can be displayed, but the edges appear diffuse and optical crosstalk occurs between adjacent symbols

Engineering Contradiction:
Improveoptical precisionVSAvoidoptical crosstalk
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The control panel is segmented into multiple functional layers: a diffusion film layer that spreads light, a symbol film layer with metal cutouts that defines symbol shapes, and a light-absorbing layer that prevents light from reaching areas outside the intended symbol regions. This segmentation allows each layer to perform its specific function, with the light-absorbing layer specifically addressing optical crosstalk by absorbing stray light between adjacent symbols.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A light-absorbing layer is introduced as an intermediary element between the diffusion film and the symbol film. This intermediate layer acts as a barrier that absorbs excess light and prevents it from causing optical crosstalk, while still allowing the desired light to pass through the metal cutouts to illuminate the symbols with sharp edges.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If high precision illumination is achieved through conventional means, then detailed symbols can be displayed, but production becomes costly and complex

Engineering Contradiction:
Improveillumination precisionVSAvoidproduction complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention uses thin flexible films (diffusion film and symbol film) that can be easily manufactured and applied to the control panel surface. The symbol film with metal cutouts can be produced using standard printing or cutting techniques, and the entire assembly can be manufactured as a thin, flexible component that is cost-effective to produce while still achieving high illumination precision.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The control panel employs a composite structure combining a diffusion film, a symbol film with metal layers, and a light-absorbing layer. This composite material approach allows each layer to contribute its specific properties: the diffusion film for light scattering, the metal layer for precise symbol definition, and the light-absorbing layer for preventing crosstalk. The combination achieves high precision illumination without requiring complex single-material solutions.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If the control panel structure is simplified, then production cost decreases, but optical crosstalk and diffuse edges worsen

Engineering Contradiction:
Improveproduction costVSAvoidoptical crosstalk
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention uses thin flexible films that are cost-effective to manufacture and apply. The symbol film can be produced using standard printing or cutting techniques, and the entire assembly can be manufactured as a thin, flexible component. This approach maintains production simplicity while the multi-layer structure effectively prevents optical crosstalk.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention changes the optical parameters of the control panel by introducing a light-absorbing layer with specific absorption characteristics. This parameter change allows the panel to absorb stray light and prevent optical crosstalk, while the overall structure remains simple and cost-effective to manufacture.

Inventive Principle:
Principle #35Parameter changes

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 provides a compact and precise control panel with high detail and cost-effective production, allowing for easy replacement and variation of symbols, while preventing optical crosstalk and ensuring sharp optical edges and uniform luminance.

Implementation Method 1

The symbol film is designed to be light-absorbing below the metal layer, in that a light-absorbing layer is present below a transparent base film of the symbol film

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a diffusion film is adhered to the mounting surface of a carrier

Methodology Applied
Scientific EffectLight diffusion: Diffusion

Implementation Method 3

The diffusion film is provided with at least one translucent blocking layer, each of which has windows in the area of the at least one keypad

Methodology Applied
Scientific EffectLight blocking: Absorption (EM radiation)

Data Source

PatentEP3280053B1Operating module for a domestic appliance
Publication Date: 2021.09.01 BSH HAUSGERATE GMBH
  • EP3280053B1 patent drawingFigure 1
  • EP3280053B1 patent drawingFigure 2
  • EP3280053B1 patent drawingFigure 3A~3B

AI summary

An operating module (1) for a household appliance (24) has a symbol film (4) applied to a mounting surface (5) of a carrier (2) with at least one touch-sensitive touch panel (9), which mounting surface (5) is below the at least one touch panel ( 9) has a luminous area (7), wherein the at least one touch panel (9) each has a metal layer (11) with at least one recess (12) introduced and the metal layer (11) is electrically conductive with an electrical connection (13) of the symbol film ( 4) is connected. A household appliance (24) has an operating module (1). The invention can be applied particularly advantageously to operating modules for hobs.