Capacitive Touch Panel With Hidden Icons and Metal Surface Sensing
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Solution Overview
Problem
Capacitive touch panels struggle to provide an aesthetically pleasing continuous metallic surface with hidden icons and discrete switching capability in automotive and domestic applications, as traditional technologies face challenges with positional resolution, calibration, glove interference, and parasitic capacitance issues.
Innovation Solution
A capacitive touch panel with a transparent or translucent substrate featuring a continuous conductive metal layer on its front surface, which remains uncluttered until illuminated, using a light source activated by capacitance changes to reveal icons and enable switching functions, employing metals like chromium and aluminum with specific light transmission levels for a polished or textured metal appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a continuous metallic surface is used to provide aesthetic appearance, then visual appeal is improved, but parasitic capacitance increases making touch detection difficult
Solution Approach 1:
The continuous metallic surface is segmented into discrete conductive regions corresponding to individual icon locations. Each region is electrically isolated from others, allowing independent capacitance sensing without the parasitic effects of a continuous surface. This segmentation enables touch detection while maintaining the aesthetic metallic appearance when illuminated.
Solution Approach 2:
The metallic surface has different electrical properties at different locations - conductive regions at icon positions versus non-conductive regions elsewhere. This local differentiation allows capacitive sensing only where needed (at icons) while maintaining continuous metallic visual appearance across the entire surface when illuminated.
2Loss of information
If icons are made visible at all times, then user interface clarity is improved, but visual clutter increases
Solution Approach 1:
Icons are illuminated periodically or on-demand rather than continuously. The system transitions between illuminated and non-illuminated states, providing clear icon visibility when needed while maintaining a clean, uncluttered metallic appearance during idle periods. This periodic illumination reduces visual clutter while ensuring information availability when required.
3Ease of operation
If transparent conductive material grid is used for touch sensing, then touch functionality is achieved, but continuous metallic surface appearance is compromised
Solution Approach 1:
A transparent or translucent substrate acts as an intermediary layer between the discrete conductive regions and the continuous metallic surface. The substrate allows light to pass through to illuminate the metallic surface while the discrete conductive regions provide touch sensing capability. This intermediary structure enables both touch functionality and continuous metallic appearance without the visual disruption of a transparent conductive grid.
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 visually appealing, continuous metallic surface with hidden icons that become visible upon illumination, offering reliable touch detection and switching capabilities without visible icons until activated, suitable for automotive and domestic use.
Implementation Method 1
A capacitive touch panel comprises a transparent or translucent panel substrate. A front surface of the substrate comprises a conductive transparent or translucent metal layer... The light source is switchable from the off state to the on state by a detected change in capacitance of the conductive transparent or translucent metal layer
Implementation Method 2
at least one light source associated with a back surface of the substrate, wherein said light source is switchable between an on state in which an illuminated icon is visible on the front surface of the panel
Data Source
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AI summary
Disclosed herein is a capacitive touch panel comprising a transparent panel substrate, a front surface of the substrate comprising a conductive translucent layer which, in use, is visible to a user; at least one light source associated with the back surface, wherein said light source is switchable between an 'on' state in which an illuminated icon is visible on the front surface of the cover panel and an 'off' state in which the illuminated icon is not visible on the front surface of the cover panel, wherein the light source is switchable from the off state to the on state by a change in capacitance of the conductive translucent layer; at least one switch associated with the back surface, wherein the switch is activable by a user pressing the touch panel in the vicinity of the illuminated icon to provide an output signal capable of performing a function.