Capacitive Operator Control Unit for Closed Industrial Housings
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Solution Overview
Problem
Existing measuring instruments in automation and process engineering face challenges in designing operator control units that allow operation through a robust, closed housing wall without interruptions, which is essential for withstanding harsh industrial conditions and maintaining hygiene standards.
Innovation Solution
The implementation of a capacitive sensor element integrated into shape-variable or elastic housing regions, comprising a multilayer printed circuit board composite with a first electrode on a rigid carrier material and a counter-electrode on a conductive layer separated by a plastic layer, allowing operation without interrupting the housing and providing a cost-effective solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a robust closed housing wall is used to withstand harsh industrial conditions, then reliability and stability are improved, but operation through the housing wall becomes difficult
Solution Approach 1:
The operating element is integrated directly into the housing wall itself, merging the housing structure with the control interface. The housing wall serves dual purposes: providing robust protection and enabling capacitive touch operation, eliminating the need for separate buttons or openings.
Solution Approach 2:
Traditional mechanical switches and pushbuttons that require physical openings or interruptions in the housing are replaced with a capacitive sensor system. This electronic sensing method allows operation through the intact housing wall by detecting changes in capacitance when the housing surface is touched.
2Ease of operation
If mechanical switches or pushbuttons are used for operation, then ease of operation is improved, but the housing structure becomes complex with interruptions
Solution Approach 1:
The operating element is integrated directly into the housing wall itself, merging the housing structure with the control interface. The housing wall serves dual purposes: providing robust protection and enabling capacitive touch operation, eliminating the need for separate buttons or openings.
3Ease of operation
If magnetic actuation or optically reflective actuation is used, then operation through closed housing is enabled, but the structure becomes complex with magnets or interruptions
Solution Approach 1:
Magnetic actuators and optical reflective systems are replaced with a capacitive sensing system. The capacitive sensor detects touch through the housing wall by measuring changes in electrical capacitance, eliminating the need for magnets, transparent panels, or other complex actuation mechanisms.
Solution Approach 2:
The housing wall itself acts as an intermediary element that transmits the touch input to the capacitive sensor. Instead of requiring separate transparent or magnetizable materials, the existing housing structure serves as the medium for both protection and input transmission.
4Ease of operation
If capacitive touch sensors with deformable metal areas are used, then operation through housing is enabled, but the solution is only applicable to very thin housing thicknesses
Solution Approach 1:
A capacitive coupling structure is introduced as an intermediary between the touch surface and the sensor element. This coupling structure transfers the capacitive signal through the housing wall without requiring direct contact or deformation of the housing itself, enabling operation through thicker housing walls.
Solution Approach 2:
The mechanical deformation approach is replaced with an electrical field-based capacitive sensing system. Instead of requiring the housing material to be deformable and thin, the system uses electrical field penetration through the housing wall to detect touch inputs, allowing operation through thicker, more robust housing.
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
This solution enables operation through a closed housing wall, ensuring robustness and cost-effectiveness while maintaining the integrity and stability of the measuring instrument, suitable for harsh industrial conditions and hygienic applications.
Implementation Method 1
A capacitive sensor element is respectively arranged under the housing regions. The sensor elements each comprise a first electrode as a lower capacitor plate and a counter-electrode arranged parallel thereabove as an upper capacitor plate. Pressing on one of the housing regions causes the respective upper capacitor plate to approach the respective lower capacitor plate, whereby a change in capacitance is triggered.
Data Source
AI summary
The invention relates to an operator control unit for a measuring instrument for process or automation engineering, the operator control unit consisting of at least two adjacently arranged control panels (10a), the control panels (10a) being operated by pressing on a respective shape-variable or elastic housing region (2a) having a respective capacitive sensor element (11) disposed thereunder. The sensor elements (11) each have a first electrode (11a) as a lower plate capacitor and a counter-electrode (11b) arranged in parallel thereabove as an upper plate capacitor, and pressing on one of the housing regions (2a) causes the respective upper plate capacitor (11b) to approach the respective lower plate capacitor (11a), thus changing the capacitance. The first electrode (11a) is attached to a first carrier material (12) and the counter-electrode (11b) is attached to a second carrier material (13). According to the invention, the housing regions (2a) are arranged adjacently to one another in an uninterrupted manner, and the sensor elements (11) are parts of a multi-layered composite printed circuit board (100), which bears against the inner sides of the housing regions (2a), wherein the composite printed circuit board (100) comprises at least the first carrier material (12), which consists of a plurality of segments of rigid circuit boards each with flexible intermediate pieces arranged therebetween, and the second carrier material (13) in the form of a conductive layer, which two carrier materials are spaced apart from one another via an interposed plastic layer (15), forming a measuring chamber (17), and wherein the plastic layer (15) has a plurality of interruptions for forming the sensor elements (11) and a decoupling region (16) between the control panels (10a).