Touch Sensor Board Local Interlayer Film for Visibility
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Solution Overview
Problem
Existing touch sensor boards face issues with screen visibility due to the optical characteristics of sensor electrodes and interlayer films, leading to deterioration in display quality and manufacture yield, as well as challenges in material selection and short-circuit failures during manufacturing.
Innovation Solution
A static capacitive touch sensor board design featuring parallel first and second electrodes connected via same-layer and different-layer connection patterns, with an interlayer film that extends between these patterns but not over the electrode regions, allowing for improved visibility and yield by controlling optical characteristics and reducing short-circuit risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an interlayer film is formed over the entire surface including electrode regions to provide insulation, then short-circuit prevention is improved, but screen visibility and transmittance are deteriorated
Solution Approach 1:
The interlayer film is selectively formed only in gap parts between adjacent electrode elements rather than covering the entire surface. This local formation approach provides insulation where needed (preventing short-circuits between adjacent electrodes) while maintaining transparency in electrode regions, thus resolving the contradiction between reliability and screen visibility.
2Illumination intensity
If sensor electrodes and interlayer film are formed with colorless transparent materials to improve visibility, then screen visibility is improved, but manufacture yield is deteriorated due to short-circuit failures
Solution Approach 1:
By forming the interlayer film locally only in gap parts between electrodes rather than uniformly across the surface, the invention maintains good optical characteristics (visibility) while effectively preventing short-circuit failures during manufacturing, thus improving manufacture yield without sacrificing visibility.
Solution Approach 2:
The interlayer film is extracted from the electrode regions and placed only in the gap parts between electrodes. This extraction eliminates the harmful effect of the film on visibility while retaining its beneficial insulating function, thereby resolving the contradiction between visibility and manufacture yield.
3Reliability
If first electrodes and second electrodes are formed with separate layers to achieve interlayer isolation, then short-circuit prevention is improved, but optical characteristics are deteriorated due to varying optical path lengths
Solution Approach 1:
Instead of forming electrodes in separate layers throughout, the invention forms both first and second electrodes on the same layer but provides local isolation only in the gap parts where adjacent electrode elements meet. This approach maintains uniform optical path length (good optical characteristics) while achieving sufficient isolation (reliability) where needed.
Data Source
AI summary
To provide a touch sensor board and the like capable of improving the visibility of the screen and the manufacture yield simultaneously. The touch sensor board includes a plurality of mutually parallel first electrodes extended along a first direction and a plurality of mutually parallel second electrodes extended along a second direction. Regarding the first and second electrodes, one of those is connected to each electrode element via a same-layer connection pattern while the other is connected to each electrode element via a different-layer connection pattern. The same-layer connection pattern and the different-layer connection pattern overlap on one another via an interlayer film formed by an insulator. Further, the interlayer film is continued from the overlapping part between the same-layer connection pattern and the different-layer connection pattern via a gap part between each of the electrode elements, and the interlayer film is formed to be continued in the gap part.