Touch Panel Nanowire Patterning via Photo-Sensitive Mask
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Solution Overview
Problem
The manufacturing process of touch panels using nanowires is complex and inefficient due to issues with alignment, etching, and high contact impedance between nanowire layers and metal traces, which affects product reliability and performance.
Innovation Solution
A manufacturing method involving a substrate with a display and peripheral area, where a metal nanowire layer and photo-sensitive conductive layer are formed, and then patterned using a developer solution to create touch sensing electrodes and peripheral conductive traces, eliminating the need for strong acid etching and reducing the complexity of the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If strong acid etching solution is used to pattern nanowire layer, then nanowire can be patterned to form touch sensing electrode, but metal trace on peripheral area is etched and product reliability decreases
Solution Approach 1:
The patent introduces a photo-sensitive conductive layer as an intermediary between the nanowire layer and the etching solution. This layer is selectively removed in the peripheral area through photolithography, exposing only the metal trace for removal while protecting the nanowire layer in the display area. The intermediary layer enables precise spatial control of the etching process, preventing unwanted etching of the metal trace while maintaining patterning precision.
2Reliability
If additional cleaning process is added to remove residual etching solution, then etching solution residue is cleaned, but manufacturing process becomes more complex
Solution Approach 1:
The patent converts the potentially harmful strong acid etching solution into a beneficial patterning tool by using it only where needed. The photo-sensitive conductive layer acts as a mask that directs the etching solution to remove only the metal trace in the peripheral area, while the nanowire layer in the display area remains protected. This approach eliminates the need for additional cleaning processes because the etching solution is precisely controlled and does not leave harmful residues in areas where it should not act.
3Manufacturing precision
If two photolithography processes and two etching processes are used for nanowire layer and metal trace patterning, then both layers are patterned, but total manufacturing process becomes more complicated
Solution Approach 1:
The patent merges the patterning of the nanowire layer and metal trace into a single integrated process. The photo-sensitive conductive layer is formed to cover the metal trace in the peripheral area, and then a single photolithography and etching process is used to pattern both the nanowire layer in the display area and the metal trace in the peripheral area simultaneously. This merging of processes reduces the total number of steps while maintaining alignment precision through the protective function of the photo-sensitive conductive layer.
4Manufacturing precision
If alignment tolerance space is preserved for alignment between touch sensing electrode and metal trace, then alignment can be achieved, but border of touch panel cannot be further narrowed
Solution Approach 1:
The photo-sensitive conductive layer serves as an intermediary that enables precise alignment without requiring additional tolerance space. By selectively removing this layer in the peripheral area through photolithography, the metal trace is exposed for etching while the nanowire layer in the display area remains protected. This intermediary mechanism allows for precise alignment between the touch sensing electrode and metal trace without needing to preserve extra alignment tolerance space, thus enabling narrower borders.
5Reliability
If contact impedance between nanowire layer and metal trace is reduced, then touch panel performance improves, but manufacturing process becomes more difficult
Solution Approach 1:
The photo-sensitive conductive layer acts as an intermediary that facilitates low-contact-impedance connections between the nanowire layer and metal trace. During the patterning process, this layer is selectively removed to create direct contact interfaces, ensuring low impedance while maintaining manufacturing simplicity. The intermediary layer enables precise control of the contact interface formation, achieving low contact impedance without complicating the manufacturing process.
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 improves manufacturing efficiency, reduces product impedance, and allows for a narrower border design, enhancing the performance and reliability of touch panels.
Implementation Method 1
exposing the photo-sensitive layer and the photo-sensitive conductive layer to define a first removing area and a second removing area
Implementation Method 2
removing the photo-sensitive layer and the metal nanowire layer in the first removing area by a developer solution
Data Source
AI summary
A manufacturing method for a touch panel includes defining a removing area of a photo-sensitive conductive layer and a photo-sensitive layer by an exposure process. On a display area, the photo-sensitive layer and a metal nanowire layer in the removing area are removed by a developer solution so as to form a touch sensing electrode on the display area. On a peripheral area, the photo-sensitive conductive layer, the photo-sensitive layer, and the metal nanowire layer in the removing area are removed by the developer solution so as to form a peripheral trace on the peripheral area. The touch sensing electrode and the peripheral trace are electrically connected with each other.