Vehicle Glass Touch Interface With Isolated Capacitive Sensing
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Solution Overview
Problem
Existing touch-sensitive operating units in vehicles often compromise between reliability, user-friendliness, and visually appealing design, particularly in terms of detection accuracy and aesthetic integration.
Innovation Solution
The proposed operating unit features a glass body with a capacitive touch-sensitive input layer on its lower side, an electrically nonconductive intermediate layer for independent appearance configuration, and an electronics unit for detecting and forwarding user inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a touch-sensitive input layer is integrated directly with the glass body, then the detection accuracy is improved, but the design flexibility and visual appearance are compromised
Solution Approach 1:
The operating element is segmented into three distinct layers: the glass body (4), the intermediate layer (5), and the input layer (6). This segmentation allows each layer to be optimized independently - the glass body for aesthetic appearance, the intermediate layer for electrical isolation, and the input layer for touch detection functionality.
Solution Approach 2:
The intermediate layer (5) acts as an intermediary between the glass body and the input layer. It provides electrical isolation while maintaining capacitive coupling, enabling the input layer to detect touches through the glass body without direct contact. This mediator layer resolves the conflict between maintaining design flexibility and achieving detection accuracy.
2Strength
If the intermediate layer is made electrically conductive to improve structural integrity, then the structural strength is improved, but the capacitive detection accuracy deteriorates
Solution Approach 1:
The intermediate layer is implemented as a thin film with specific electrical properties (surface resistance of at least 20 V/A). This thin film provides sufficient structural support and mechanical integrity while maintaining electrical transparency for capacitive detection. The thin film allows capacitive coupling between the input layer and the finger touch without requiring high electrical conductivity.
3Area of stationary object
If the input layer covers the entire glass body surface for comprehensive touch detection, then the detection coverage is improved, but the manufacturing complexity increases
Solution Approach 1:
The intermediate layer serves multiple functions simultaneously: it provides electrical isolation between the glass body and input layer, maintains mechanical structural integrity, enables capacitive coupling for touch detection, and allows for design flexibility. This multi-functionality reduces the need for additional specialized components, thereby simplifying the overall manufacturing process despite the large coverage area.
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 reliable and user-friendly operation of vehicle functions with a visually attractive design, ensuring high detection accuracy and aesthetic integration by utilizing a capacitive touch-sheet and nonconductive intermediate layer.
Implementation Method 1
The touch-sensitive input layer is particularly preferably configured for the capacitive detection of an object, in particular a finger, on the surface of the glass body
Implementation Method 2
the intermediate layer preferably has a reflection factor of at least 20%, preferably at least 25%, particularly preferably at least 30%, on its side facing toward the glass body. Because of this relatively high reflection factor, the color of the preferably lustrous intermediate layer is a dominant factor for the appearance of the glass body
Data Source
AI summary
Please substitute the new Abstract submitted herewith for the original Abstract: An operating unit of a vehicle includes an operating element. The operating element includes a glass body, a touch sensitive input layer, an electrically nonconductive intermediate layer, and a base. The glass body has an upper side which forms a visible and touchable surface of the operating element, and a lower side opposite the upper side. The touch-sensitive input layer is on the lower side of the glass body and is configured to detect a touch on the upper side of the glass body. The electrically nonconductive intermediate layer is located between the lower side of the glass body and the input layer. The operating element is mounted on the base.