Mesh Touch Panel Sensing Lines for Display Visibility
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Solution Overview
Problem
Touch panels using transparent conductive films face challenges in achieving high sensing accuracy and display quality due to high resistance values and visibility issues, while metal film-based panels offer better accuracy but degrade visibility when upsized.
Innovation Solution
The use of mesh-like conductors for sensing lines, combined with dummy patterns, reduces line resistance and enhances sensitivity, while maintaining display quality by forming an apparently continuous mesh pattern that allows more light to pass through.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If sensing lines are made of transparent conductive film, then visibility is improved, but sensing accuracy deteriorates due to high resistance value
Solution Approach 1:
The sensing lines are divided into multiple parallel thin lines (first and second sensing lines) arranged in a mesh-like pattern. This segmentation allows each individual line to be very thin (reducing visibility) while the collective bundle provides sufficient conductive cross-section (maintaining low resistance). The multiple lines work together to achieve both transparency and electrical performance.
Solution Approach 2:
The invention transitions from using a single thick conductive line to using multiple thin lines arranged in a two-dimensional mesh pattern. By adding the spatial dimension and distributing the conductive function across multiple lines at different positions, the system achieves both optical transparency (thin individual lines) and electrical conductivity (multiple parallel paths).
2Illumination intensity
If sensing lines are formed as bundles of thin lines, then visibility is improved, but resistance value increases
Solution Approach 1:
Multiple thin sensing lines (first and second sensing lines) are merged into a functional bundle where they are electrically connected through the mesh-like conductor structure. This combining allows the system to benefit from the transparency of individual thin lines while achieving the low resistance of a thick conductor through the parallel connection of multiple lines.
Solution Approach 2:
The mesh-like conductor structure serves multiple functions simultaneously: it provides optical transparency through thin individual lines, maintains low resistance through multiple parallel conductive paths, and improves manufacturing robustness through redundant connections. Each thin line contributes to both optical and electrical performance.
3Reliability
If sensing lines are made of plain lines, then resistance value is reduced, but visibility deteriorates due to large line areas
Solution Approach 1:
Instead of using a single plain line with large cross-section, the invention segments the conductive function into multiple thin lines arranged in a mesh pattern. Each line has small individual area (maintaining transparency) but the collective arrangement provides sufficient total conductive area (maintaining low resistance).
Solution Approach 2:
The mesh-like structure allows different regions to have different properties: individual line regions are thin and transparent, while the collective bundle regions provide adequate conductivity. The spatial distribution creates local transparency where needed while maintaining overall electrical performance.
4Area of stationary object
If touch panels are upsized, then display area is increased, but sensing accuracy deteriorates due to increased parasitic capacitance and line resistance
Solution Approach 1:
The sensing lines are segmented into multiple thin lines arranged in a mesh pattern, which reduces the capacitance of each individual line. This segmentation allows the touch panel to be upsized while maintaining sensing accuracy, as the distributed thin lines have lower parasitic capacitance compared to fewer thick lines covering the same area.
Solution Approach 2:
By transitioning to a mesh-like two-dimensional arrangement of thin lines, the invention reduces line resistance and parasitic capacitance per unit area. This dimensional approach allows larger display areas to be covered while maintaining low resistance paths and low capacitance, enabling upsizing without sacrificing sensing accuracy.
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 approach improves sensitivity and display quality by reducing line resistance and minimizing the impact of pattern defects, while maintaining visibility and reducing yield loss.
Implementation Method 1
the first series of conductive material patterns (conductor elements) formed of a thin conductive film as sensing conductors for sensing capacitance
Implementation Method 2
The capacitance controlled oscillator of such a touch panel can be a relaxation oscillator or a hysteresis oscillator. The oscillation cycle of such an oscillator is generally determined by the charge/discharge time constants of resistive and capacitive elements
Data Source
AI summary
An object is to obtain a touch panel with improved sensitivity and enhanced display quality. A touch panel according to the present invention includes a touch screen including a plurality of first sensing lines formed of mesh-like conductors and arranged in parallel on a substrate, an insulating film formed over the substrate and the first sensing lines, a plurality of second sensing lines formed of mesh-like conductors and arranged in parallel on the insulating film, first dummy patterns arranged in areas opposed to areas between adjacent first sensing lines through the insulating film, and having a form as part of the mesh forms of the first sensing lines such that the adjacent first sensing lines form an apparently continuous mesh form in plan view, and second dummy patterns arranged in areas opposed to areas between adjacent second sensing lines through the insulating film, and having a form as part of the mesh forms of the second sensing lines such that the adjacent second sensing lines form an apparently continuous mesh form in plan view.