Touch Cover Assembly With Recessed Light Entry and Venting
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Solution Overview
Problem
Input assemblies with touch-sensitive operating surfaces face challenges in achieving uniform light distribution and mechanical stability while maintaining high-quality haptic properties, as high material thickness is required for backlighting, which compromises light transmission and rigidity.
Innovation Solution
The input assembly features a cover with a transparent thermoplastic material, a recessed entry surface for reduced layer thickness, a ventilated hollow volume to prevent air pressure-related positional changes, and a capacitive touch sensor system with a conductive film layer structure, ensuring improved light transmission and mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the cover is made with high material thickness to prevent damage and provide structural stability, then mechanical strength and haptic properties are improved, but light transmission and uniformity of backlighting deteriorate
Solution Approach 1:
The patent applies local quality by creating a recessed region in the cover where the material thickness is reduced specifically in the area where light enters and passes through. This localized thinning allows improved light transmission and more uniform backlighting distribution without compromising the overall mechanical strength of the cover, as other regions maintain their original thickness for structural support.
2Illumination intensity
If the cover is thinned to improve light transmission, then illumination uniformity is improved, but mechanical stability and rigidity deteriorate
Solution Approach 1:
The recessed region is strategically positioned and dimensioned to affect only the light path area. The cover maintains its full thickness in surrounding areas, preserving overall rigidity and mechanical stability while achieving improved light transmission and uniformity in the specific region where backlighting occurs.
3Illumination intensity
If the cover is made thinner to achieve uniform light distribution, then backlighting homogeneity is improved, but force flow and touch detection reliability deteriorate
Solution Approach 1:
The recessed region is localized to the area behind the luminous surface, creating optimal light transmission conditions without affecting the overall structural integrity of the cover. This ensures that force flow from touch points to detection means remains reliable, maintaining touch detection accuracy while achieving uniform backlighting.
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 configuration enhances the homogeneity of touch sensitivity and light distribution while maintaining mechanical stability, ensuring reliable touch detection and uniform backlighting.
Implementation Method 1
light from a light source has to be transmitted through the cover
Implementation Method 2
light is coupled into the cover from a light source arranged on a side of the cover facing away from the operator, via an entry surface in a rear surface
Implementation Method 3
a capacitive touch sensor system with a film layer structure with one or several electrodes formed from a conductive coating is used in such input assemblies
Data Source
AI summary
The present disclosure relates to an input assembly, including: a cover having a touch-sensitive operating surface facing an operator and a rear surface facing away from the operator, wherein the operating surface contains a luminous surface; a support arranged on the side of the cover facing away from the operator; a light source arranged on the support to couple light into the cover via an entry surface, in order to backlight the luminous surface, wherein the cover is transparent in the region between the entry surface and the luminous surface; a transparent film layer structure arranged between the cover and the light source, with a conductive coating for forming an electrode for a capacitive touch sensor system; wherein the entry surface is formed by a recess in the rear surface of the cover, and wherein a ventilated hollow volume is formed between the film layer structure and the entry surface.