Opaque Passivation Layer for Touch Sensor Trace Concealment
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Solution Overview
Problem
Touch sensitive devices face challenges in hiding conductive metal traces from user view and protecting them from corrosion, which restricts sensor size and adds manufacturing complexity due to the visibility of non-transparent metal traces.
Innovation Solution
Incorporating an opaque passivation layer made from organic or inorganic materials, such as acrylic-based materials, between the cover material and conductive traces in touch sensitive devices to conceal and protect the metal traces from corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal traces are used to couple transparent traces with bus lines, then electrical connectivity is achieved, but the metal traces become visible to users and require additional black masking
Solution Approach 1:
An opaque passivation layer is introduced as an intermediary between the metal traces and the cover glass. This passivation layer serves dual purposes: it protects the metal traces from corrosion while simultaneously making them invisible to users, eliminating the need for separate black masking layers and simplifying the overall device structure.
Solution Approach 2:
The opaque passivation layer performs multiple functions simultaneously: it provides corrosion protection for the metal traces, conceals the traces from user view, and eliminates the need for additional black masking layers. This multi-functionality reduces device complexity and manufacturing steps.
2Device complexity
If black masking is used to hide metal traces, then traces are concealed from view, but sensor size is restricted and manufacturing complexity increases
Solution Approach 1:
The opaque passivation layer acts as an intermediary that directly conceals the metal traces beneath the cover glass, eliminating the need for separate black masking layers. This approach maintains aesthetic appearance while allowing the sensor to extend to the edges of the display without visible traces.
Solution Approach 2:
The corrosion protection function and the trace concealment function are merged into a single opaque passivation layer. This consolidation eliminates the need for separate black masking layers, thereby increasing sensor size while maintaining aesthetic appearance and reducing manufacturing complexity.
3Ease of manufacture
If metal traces are exposed without passivation, then manufacturing is simpler, but traces are susceptible to corrosion
Solution Approach 1:
The opaque passivation layer serves as a protective intermediary between the metal traces and the corrosive environment. It shields the traces from moisture and oxygen, preventing corrosion while maintaining manufacturing simplicity through a single deposition process.
Solution Approach 2:
The opaque passivation layer provides self-protection for the metal traces by forming a corrosion-resistant barrier. This eliminates the need for additional protective measures or maintenance, enhancing reliability while keeping the manufacturing process simple.
Data Source
AI summary
A touch sensitive device that includes a touch sensor having an opaque passivation layer is disclosed. The opaque passivation layer can be made from an organic or inorganic material, such as acrylic. The opaque passivation layer can be positioned in the touch sensitive device between the cover material of the device and conductive traces located on the touch sensor to hide the conductive traces from the user's view and protect the conductive traces from corrosion. Processes for making the touch sensitive devices that include a touch sensor having an opaque passivation layer are also disclosed.