Capacitive Sensor Film Structure for Durable Backlit Input Panels
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Solution Overview
Problem
Capacitive sensors with a film layer structure in input devices face challenges in production accuracy and durability, particularly under adverse conditions, and require precise assembly and maintenance to ensure uniform backlighting and accurate force measurement.
Innovation Solution
A flat panel input device with a film layer structure that includes capacitive sensors and a support, where the control surfaces are visible to the operator, and a light-conducting layer for uniform backlighting, with a stability-providing connection between the panel and support using thermoplastic webs to maintain positional accuracy and prevent 'crosstalk' between control surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a film layer structure with capacitive sensors is used, then manufacturing cost is reduced and spatial resolution is improved, but positioning accuracy and durability deteriorate under adverse conditions
Solution Approach 1:
The patent uses a flexible film layer structure containing capacitive sensors that can be integrated into the control surface assembly. This flexible film approach reduces manufacturing complexity and cost while maintaining the necessary sensing functionality across multiple control surfaces.
Solution Approach 2:
The control surface assembly serves multiple functions: it provides the user interface for control inputs, integrates capacitive sensing capabilities, and incorporates backlighting functionality. This multi-functional integration reduces the need for separate components and assembly steps, improving ease of manufacture.
2Ease of manufacture
If a film layer structure with capacitive sensors is used, then manufacturing cost is reduced, but durability and permanent position retention worsen under adverse ambient conditions
Solution Approach 1:
The patent employs composite material structures in the control surface assembly, combining different materials with complementary properties. The control surface assembly integrates rigid structural elements with flexible sensing films, creating a composite structure that maintains durability while enabling cost-effective capacitive sensing.
Solution Approach 2:
The flexible film layer containing capacitive sensors is designed to withstand adverse ambient conditions while maintaining its sensing functionality. The film structure is protected within the control surface assembly, which provides mechanical support and environmental protection, ensuring durability without significantly increasing manufacturing cost.
3Measurement precision
If precise assembly positioning is implemented, then capacitive detection accuracy is improved, but device complexity and production difficulty increase
Solution Approach 1:
The control surface assembly is designed to provide a stable reference potential for the capacitive sensors. By ensuring that the control surface maintains a consistent electrical potential across all sensing areas, the system achieves accurate capacitive detection without requiring complex positioning mechanisms or calibration procedures.
Solution Approach 2:
The control surface assembly serves as both the structural support and the electrical reference for the capacitive sensors. This integrated design eliminates the need for separate positioning mechanisms and reference structures, reducing assembly complexity while maintaining detection accuracy.
4Illumination intensity
If uniform backlighting is implemented, then visual clarity is improved, but manufacturing precision requirements and production difficulty increase
Solution Approach 1:
The backlighting system is designed with local lighting elements distributed across the control surface assembly. Each backlighting element is positioned to illuminate specific control surface areas, and the control surface structure itself helps distribute and uniformize the light. This approach achieves uniform backlighting without requiring extremely precise assembly tolerances.
Solution Approach 2:
The control surface assembly serves dual purposes: it provides the structural framework for the user interface and acts as the light-distributing medium for backlighting. This integration means that the same structural components that define control surface positions also ensure uniform light distribution, eliminating the need for separate precision alignment procedures.
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
Enhances durability and reproducibility of capacitive detection while providing haptic feedback and maintaining production cost-effectiveness, ensuring accurate force measurement and touch detection with improved spatial resolution and visual clarity.
Implementation Method 1
the panel, on the side facing towards the support, has a light-conducting layer of transparent of translucent material, which covers the luminous surfaces in a connecting manner
Implementation Method 2
the film layer structure, which defines an array of capacitive sensors... the capacitive sensors being configured as force sensors
Data Source
AI summary
The present disclosure relates to an input device comprising a flat panel defining an array of control surfaces, a support disposed on a side of the panel, and a substantially flat film layer placed between the panel and the support defining an array of capacitive sensors, wherein each control surfaces comprises backlightable luminous surfaces and are disposed on a surface of the panel facing towards an operator, wherein each capacitive sensor forms a measuring capacitance assigned to one control surface, wherein the panel has a light-conducting layer covering the luminous surfaces, wherein a lighting means is provided for each control surface for backlighting the associated luminous surface of the control surface while transmitting light through the light-conducting layer, wherein the support forms a web which protrudes towards the panel and is connected to the panel in order to fix the film layer structure between the panel and the support.