Touch Panel Insulating Strings for Alignment Accuracy
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Solution Overview
Problem
In touch panels with single-layer conductive structures, misalignments and errors in the bridge formation due to substrate expansion and contraction, as well as patterning process inaccuracies, lead to widened gaps between electrodes, affecting functionality and visual quality.
Innovation Solution
The implementation of a touch panel design featuring insulating strings with a steep taper, which provides insulation by height difference, eliminating the need for spacing between electrodes and minimizing bridge size, thereby improving alignment and visual aesthetics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gap is provided between the touch driving electrode and the adjacent touch sensing electrode for insulation, then electrical insulation is improved, but alignment accuracy and visual quality deteriorate due to errors in the touch sensing layer pattern
Solution Approach 1:
The patent introduces insulating strings with a steep taper that extend vertically from the substrate, creating a height difference (z-dimension) between the touch driving electrode and touch sensing electrode. This vertical dimension provides electrical insulation through the height difference rather than relying solely on horizontal spacing, thereby maintaining alignment accuracy while ensuring proper insulation.
2Ease of manufacture
If multiple exposures are performed in the patterning process, then complete pattern formation is achieved, but alignment errors accumulate due to substrate expansion and contraction
Solution Approach 1:
The insulating strings serve as an intermediary structure that simplifies the alignment requirement. By providing insulation through height difference rather than precise horizontal positioning, the insulating strings act as a mediator that reduces the cumulative alignment errors from multiple exposures while still enabling complete pattern formation.
3Reliability
If the bridge width is increased to compensate for misalignment, then connection reliability is improved, but electrical impedance increases and visual quality deteriorates
Solution Approach 1:
The patent moves the insulation function from the horizontal plane to the vertical dimension by introducing insulating strings with steep tapers. This allows the bridge to maintain a narrow width for better visual quality and lower electrical impedance while still achieving reliable insulation through the height difference provided by the insulating strings.
Data Source
AI summary
A touch panel of improved appearance and function includes a substrate, first bridges, insulating strings, first electrodes, and second electrode strings. Each insulating string extends along a first direction and covers the first bridges. The insulating strings are spaced apart from each other in a second direction intersecting with the first direction. Adjacent first electrodes in the second direction are electrically connected to one first bridge to form a first electrode string. Each second electrode string is on one of the insulating strings. Each first electrode string and the adjacent second electrode string are insulated from each other by a difference in height along one insulating string. A method for making the touch panel and a touch display device using the touch panel are also disclosed.