Flexible Capacitive Trim Sensors for Hidden Touch and Lighting
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Solution Overview
Problem
Existing sensor and lighting elements placed behind a soft surface substrate face reduced sensitivity and signal-to-noise ratio due to the material stack, leading to poor light intensity and color shift, and the operator can feel components, which affects the design and user experience.
Innovation Solution
The solution involves securing sensor and lighting elements directly to the back side of a thermoplastic polyolefin outer show surface layer, using flexible capacitive sensors and side-firing LEDs with optically clear and blackout silicone molding to minimize light path losses and prevent component feel, while embedding components in a slightly harder but thin layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensor and lighting elements are placed behind the substrate to sense through the soft surface, then the complete stack up of materials is covered, but sensitivity is reduced and signal to noise ratio is lower
Solution Approach 1:
Instead of placing sensors behind the substrate to sense through it, the patent inverts the approach by placing sensors on the exterior show surface layer, eliminating the need to sense through multiple material layers and thereby improving sensitivity and signal-to-noise ratio
2Reliability
If sensor and lighting elements are placed between the skin material and substrate, then sensing through soft surface is achieved, but components can be felt by the operator
Solution Approach 1:
The patent moves components from the interior layer (between skin and substrate) to the exterior show surface layer, changing the dimensional position of components. This allows the soft foam layer to remain between the operator's finger and all components, preventing them from being felt while maintaining sensing capability
3Illumination intensity
If light source is placed on the rear of the substrate to illuminate icons, then the complete stack up of material is illuminated, but light intensity at the surface is poor and color shift is evident
Solution Approach 1:
The patent extracts the light source from the rear of the substrate and relocates it to the exterior show surface layer, eliminating the need for light to traverse through multiple material layers. This reduces light path complexity and improves light intensity and color stability at the icon location
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 arrangement enhances sensitivity and signal-to-noise ratio, reduces light bleed, and maintains softness, providing improved light transmission and color stability, while ensuring components are not felt by the operator, thus enhancing the user interface.
Implementation Method 1
A sensor element of the sensor and lighting element includes flexible capacitive sensors
Implementation Method 2
a light emitting diode (LED) frame
Data Source
AI summary
A sensor and lighting element configured to be positioned directly behind a first surface of an automotive trim article. A trim element, included: a sensor element and lighting element; and a hidden front functionality thermoplastic polyolefin (TPO) film.