Touch Panel Conductive Pattern Darkening for Low Reflectivity
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Solution Overview
Problem
Touch screens in electronic devices suffer from visibility issues due to external light reflectivity, which affects user experience and device thickness, and attempts to reduce reflection can compromise pixel aperture ratio.
Innovation Solution
A touch panel design incorporating a darkening layer with a multi-layer structure over conductive patterns to reduce external light reflectivity, comprising a base layer, conductive patterns, and an insulating layer, with specific materials and thicknesses to achieve low reflectivity and maintain touch sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a darkening layer is added to reduce external light reflectivity, then touch sensor visibility is reduced, but device thickness increases
Solution Approach 1:
The patent applies composite materials by creating a multi-layer darkening structure comprising a lower layer, middle layer, and upper layer with specific material compositions. Each layer has distinct optical properties (extinction coefficients and refractive indices) that work together to achieve superior light reflection reduction compared to single-layer solutions, thereby reducing touch sensor visibility while controlling overall thickness.
Solution Approach 2:
The patent utilizes parameter changes by precisely controlling the optical parameters of each layer including extinction coefficients (k ≤ 2.5), refractive indices (n ≤ 2.3), and thicknesses (500-850 Å total). By optimizing these parameters, the darkening layer achieves effective light reflection reduction while maintaining acceptable device thickness.
2Ease of manufacture
If conventional single-layer darkening is used, then manufacturing is simpler, but reflectivity reduction is insufficient
Solution Approach 1:
The patent employs composite materials through a three-layer darkening structure where each layer has specific material properties. The lower layer, middle layer, and upper layer are composed of materials with controlled extinction coefficients and refractive indices, creating a composite system that achieves superior reflectivity reduction compared to conventional single-layer approaches.
Solution Approach 2:
The patent applies local quality by assigning different material properties to different layers of the darkening structure. Each layer has specifically tailored optical characteristics (extinction coefficient, refractive index, thickness) optimized for its position, allowing the system to achieve better overall performance than uniform single-layer designs while remaining manufacturable.
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 effectively reduces external light reflectivity to less than 4%, minimizing visibility of touch sensors while maintaining touch sensitivity and increasing the aperture ratio of pixels, thereby enhancing user experience and device thinness.
Implementation Method 1
a darkening layer disposed over the conductive layer, wherein each of the first and second conductive patterns may have an external light reflectivity lower than that of the conductive layer
Implementation Method 2
a lower layer disposed directly on the conductive layer and including a first conductive material having an extinction coefficient of about 2.5 or less, an upper layer disposed on the lower layer and including a second conductive material having an extinction coefficient of about 2.5 or less, and a middle layer disposed between the upper layer and the lower layer and in contact with each of the upper and lower layers and including a third conductive material having a refractive index of about 2.3 or less
Data Source
AI summary
A touch panel is manufactured by a method that decreases undesirable reflections of external light while improving the visibility of emitted light. The touch panel includes a base layer including an active region responsive to an external touch to generate an electronic signal and a peripheral region adjacent to the active region, and a first conductive pattern disposed on the active region and a second conductive pattern disposed on the peripheral region, each of the first conductive pattern and the second conductive pattern including a conductive layer having an external light reflectivity and a darkening layer disposed over the conductive layer. External light reflectivity of each of the first and second conductive patterns is lower than that of the conductive layer.