Touch Panel Wiring Line Width Variation for Display Visibility
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Solution Overview
Problem
Projected capacitive touch panels with thin metal wires for display devices face issues of reduced luminance and visibility due to the metal wires overlapping pixel parts, leading to glare and deterioration in appearance, especially as sub-pixel sizes decrease and black matrix widths thin.
Innovation Solution
A touch panel design where the first and second electrode groups have wiring lines with varying line widths, positioned to overlap the light-shielding part, with the outermost region having a smaller line width than the innermost region, and a dielectric part is used to minimize light reflection and improve invisibility, while redundant lines ensure conductive paths without obstructing light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thin metal wires are used for X-axis and Y-axis electrodes to reduce resistance and enable large screen display, then wiring resistance is reduced, but the metal wires overlap pixel parts and shield light, reducing luminance and causing visibility issues
Solution Approach 1:
The patent positions the thin metal wires in the thickness direction (Z-axis) rather than only in the planar direction. By stacking electrode substrates with wires arranged in parallel in the thickness direction, the wires are located above or below the pixel parts in the Z-axis, allowing light to pass through without being blocked, thus resolving the contradiction between maintaining low resistance and preserving luminance.
Solution Approach 2:
The patent embeds the thin metal wires within the layered structure of the display device, positioning them between the pixel part and the outer surface. The wires are nested in the thickness direction within the stacked substrate structure, allowing them to function as electrodes while minimizing their impact on light transmission from the pixel parts.
2Reliability
If thin metal wires with regular repeated shapes are arranged in grid-like form to form electrodes, then electrode functionality is achieved, but periodic intersecting parts are generated with black matrix that shield light and cause moire, deteriorating display quality
Solution Approach 1:
The patent introduces asymmetric positioning of the thin metal wires relative to the black matrix grid. By offsetting the wire arrangement from the black matrix periodicity, the regular repeated patterns align in a way that minimizes periodic intersecting parts, thereby reducing moire generation while maintaining electrode functionality.
Solution Approach 2:
The patent resolves the moire issue by moving the wire arrangement into the thickness dimension. By stacking wires in the Z-axis direction rather than only arranging them in the XY-plane grid, the periodic intersecting parts are eliminated or minimized, as the wires are positioned above or below the black matrix rather than overlapping in the same plane.
3Measurement precision
If sub-pixel sizes are decreased and black matrix width is thinned to improve display resolution, then display definition is improved, but the thin metal wires become more visible and cause glare, deteriorating appearance quality
Solution Approach 1:
The patent positions thin metal wires in the thickness direction (Z-axis) by stacking electrode substrates, placing them above or below the pixel parts rather than in the same plane. This dimensional relocation allows the wires to remain functional while being less visible and causing less glare, as they are positioned out of the primary light transmission path from the thin sub-pixels.
Solution Approach 2:
The patent applies different line widths to different regions of the thin metal wires. By making the line width smaller in the outermost region and larger in the innermost region, the wires are optimized for both functionality and visibility. The varying line width allows the wires to be less visible in critical viewing areas while maintaining sufficient conductive paths in inner regions.
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 design enhances the invisibility of the wiring lines, improves display quality, reduces power consumption, and prevents glare by minimizing light reflection, thus maintaining high transmittance and appearance quality.
Implementation Method 1
a dielectric part interposed between the first electrode part and the second electrode part... minimizing light reflection and improving invisibility
Data Source
AI summary
Provided are a touch panel, a displaying unit, and a touch panel manufacturing method that make it possible to thin a wiring line and that suppress visibility of a wiring line to improve appearance. A first electrode group extends in a direction intersecting with a second electrode group in plan view. A large part of a first wiring line or the entire first wiring line is arranged so as to overlap a light-shielding part in the entire line width thereof in plan view. On the basis of a display device, a first electrode part is located on an outer side of a dielectric part and the first wiring line and/or a second wiring line has a line width varied according to a height, and has a line width in an outermost region smaller than a line width in an innermost region.