Capacitive Control Panel Assembly Without Adhesive Bonding

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Solution Overview

Problem

Existing touch-sensitive control devices with capacitive sensors are complex and costly due to intricate assembly and adhesive bonding, making them difficult to repair and maintain.

Innovation Solution

A method involving the production of a one-piece base body coupling element with embedded capacitive sensor elements using injection molding, allowing for simple assembly and disassembly without adhesive bonding, and enabling efficient electrical coupling through conductive coupling elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional assembly methods with multiple components and adhesive bonding are used, then the device achieves functional requirements, but the manufacturing complexity and cost increase

Engineering Contradiction:
Improvefunctional performanceVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple separate components (base body, coupling elements, and capacitive sensor elements) into a single integrated base body through injection molding. The coupling elements are formed directly as part of the base body structure, eliminating the need for separate assembly steps and adhesive bonding, while maintaining all necessary functional interfaces for electrical and mechanical coupling.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The base body serves multiple functions simultaneously: it provides the structural housing, contains the coupling elements for electrical connection, and integrates the capacitive sensor elements for touch detection. This multi-functional design reduces the number of separate components needed while maintaining all required functions.

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

2Strength

If traditional assembly methods with adhesive bonding are used, then the device achieves structural integrity, but the ease of repair and maintenance decreases

Engineering Contradiction:
Improvestructural integrityVSAvoiddisassembly ease
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

While the base body is integrated, the design maintains functional segmentation through the coupling elements that create distinct electrical and mechanical interfaces. The printed circuit board and control panel can still be separately assembled and disassembled by releasing the coupling elements, enabling easy repair without destroying the integrated base body structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coupling elements are designed to provide secure mechanical and electrical connection during operation, but can be easily released when needed for maintenance. The transition from a permanently bonded state to a reversible connection state allows the device to maintain structural integrity during use while enabling easy disassembly for repair.

Inventive Principle:
Principle #15Dynamics

3Reliability

If multiple separate components are used, then the device achieves functional requirements, but the manufacturing cost increases

Engineering Contradiction:
Improvefunctional performanceVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The base body, coupling elements, and capacitive sensor elements are manufactured as a single integrated component through injection molding, eliminating the need for separate manufacturing processes, inventory management of multiple parts, and assembly operations. This significantly reduces manufacturing complexity and cost while maintaining all necessary functional interfaces.

Inventive Principle:
Principle #5Merging (Combining)

4Stability of the object's composition

If adhesive bonding is used for assembly, then the device achieves structural stability, but the productivity decreases

Engineering Contradiction:
Improveassembly stabilityVSAvoidassembly speed
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The base body is manufactured as a single integrated component through injection molding, eliminating the need for adhesive bonding and separate assembly operations. This dramatically increases production speed while maintaining structural stability through the integrated design that provides inherent mechanical and electrical coupling.

Inventive Principle:
Principle #5Merging (Combining)

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

Facilitates cost-effective, efficient, and easy-to-maintain production of touch-sensitive devices with improved capacitive coupling, suitable for various applications including medical and food industry environments.

Implementation Method 1

a plurality of electrically conductive coupling elements are formed or embedded on or in the base body produced from plastic by an injection molding process

Methodology Applied
Scientific EffectInjection molding:

Implementation Method 2

a capacitive sensor element that can detect a change in capacitance and convert it into electronic signals

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 3

The electronics in the touch-sensitive operating device use the capacitive sensor element to measure a change in electrical capacitance generated by a voltage drop between two electrodes

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 4

at least one electrically conductive coupling element is arranged between the contact surface of the base body and the at least one capacitive sensor element arranged on the printed circuit board in order to transmit a change in capacitance

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4027522B1Operating device and method for manufacturing and assembling an operating device
Publication Date: 2025.07.02 HOFFMANN KRIPPNER
  • EP4027522B1 patent drawingFigure 1~2
  • EP4027522B1 patent drawingFigure 3~4
  • EP4027522B1 patent drawingFigure 5

AI summary

The invention relates to a method for manufacturing and assembling an operating device (2) and the operating device (2) according to the invention, comprising at least one capacitive sensor element (3) for detecting a touch or approach to a control panel (4), wherein the operating device (2) has a base body (6) and a circuit board (7), wherein the base body (6) can be fixed to a contact surface (18) of the control panel (4), wherein the circuit board (7) with at least one light source (17) for illuminating the control panel (4) can be arranged on the base body (6) at a distance from the contact surface (18), and wherein at least one electrically conductive coupling element (9) is arranged between the contact surface (18) of the base body (6) and the at least one sensor element (3) which is arranged on the circuit board (7).to transmit a change in capacitance in the area of ​​the control panel (4) to the at least one sensor element (3). According to the invention, the at least one coupling element (9) is formed or embedded in the base body (6) produced by injection molding of plastic in an assembly step (8), thereby producing a one-piece base body coupling element (11), and wherein in a subsequent assembly step (10) the circuit board (7) is fixed to the base body coupling element (11) and the at least one sensor element (3) is pressed against the coupling element (9).