Touch Panel Through Hole Alignment via Opaque Connecting Pads
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Solution Overview
Problem
Conventional capacitive touch panels face misalignment issues due to thermal expansion and manufacturing errors, causing positional shifts in the through holes of the insulating layer, which affect the alignment of the second bridge portion and lead to electrical coupling errors between second electrodes.
Innovation Solution
The use of opaque connecting pads made of conductive materials like Cu or Ag, in conjunction with a negative-type photoresist insulating layer, allows for precise positioning of through holes and accurate electrical coupling between second electrodes by forming second bridge portions on the insulating layer, thereby maintaining alignment and improving connection yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing processes are used, then production efficiency is maintained, but misalignment occurs between through holes and second bridge portions due to thermal expansion and manufacturing errors
Solution Approach 1:
The insulating layer is formed with through holes at predetermined positions before the second bridge portions are formed. This preliminary positioning ensures that subsequent second bridge portions can be accurately aligned with the through holes, preventing misalignment caused by thermal expansion and manufacturing errors during later processing steps.
Solution Approach 2:
The insulating layer acts as an intermediary structure that defines through holes at precise positions. This intermediary element serves as a reference framework that guides the formation of second bridge portions, ensuring accurate alignment while isolating the electrode structures from direct thermal interaction.
2Illumination intensity
If the insulating layer is made transparent, then optical performance is improved, but positioning accuracy of through holes deteriorates
Solution Approach 1:
The insulating layer is configured to be transparent in regions where light transmission is needed, while maintaining precise through hole positioning in specific local areas. This local differentiation allows the insulating layer to simultaneously provide optical performance in display regions and positioning accuracy in electrode connection regions.
Solution Approach 2:
The solution addresses the conflict between transparency and positioning accuracy by considering different functional dimensions of the insulating layer. The transparency property is optimized for optical dimensions, while the through hole positioning precision is optimized for manufacturing dimensions, allowing both requirements to be satisfied in their respective domains.
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 method ensures accurate positioning of through holes and enhances the electrical coupling between second bridge portions and second electrodes, reducing misalignment and improving the overall reliability of the touch panel's electrical connections.
Implementation Method 1
the insulating layer is made of a negative type photoresist and the through holes are formed at predetermined positions
Data Source
AI summary
A touch panel includes a substrate, a plurality of first electrodes, a plurality of first bridge portions, and a plurality of second electrodes on the substrate. A plurality of connecting pads is on a side of the second electrodes away from the substrate. The connecting pads are made of a non-transparent conductive material. An insulating layer is on the substrate and covers the first electrodes, the first bridge portions, and the second electrodes. The insulating layer defines a plurality of through holes. Each connecting pad is exposed from the insulating layer by one through hole. A plurality of second bridge portions is on a side of the insulating layer away from the substrate. Each of the second bridge portions extends into adjacent two through holes to electrically couple adjacent two second electrodes.