Dual-Substrate Capacitive Touch Panel With Separated Touch-Layer Fabrication
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Solution Overview
Problem
Conventional capacitive touch panels face low production yield due to the risk of scratching or staining of the upper touch sensitive layer during the fabrication process of the lower touch sensitive layer, limiting their application to large-size touch panels.
Innovation Solution
The capacitive touch panel design includes a first substrate with a lower touch sensitive layer, a lower conductor layer, a transparent insulation adhesive layer, an upper conductor layer, an upper insulation ink layer with through slots filled with a conductive layer, and an upper touch sensitive layer, allowing for separate fabrication processes for the lower and upper touch sensitive layers, utilizing mature single-sided circuit substrate techniques to enhance yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the upper touch sensitive layer is formed first on the first glass substrate, then the lower touch sensitive layer can be formed subsequently, but the completed upper touch sensitive layer easily gets scratched or stained during the fabrication process of the lower touch sensitive layer, resulting in low production yield
Solution Approach 1:
The invention divides the touch panel into two separate substrates: a first substrate for forming the lower touch sensitive layer and a second substrate for forming the upper touch sensitive layer. This segmentation allows each layer to be fabricated independently on separate substrates, eliminating the risk of damage to the upper layer during lower layer fabrication, thereby resolving the contradiction between ease of manufacture and production yield.
2Productivity
If the upper touch sensitive layer is formed first on the first glass substrate, then the lower touch sensitive layer can be formed subsequently, but the completed upper touch sensitive layer easily gets scratched or stained during the fabrication process of the lower touch sensitive layer, limiting the application to large-size touch panels
Solution Approach 1:
By segmenting the touch panel into two separately fabricated substrates that are later bonded together, the invention enables high-yield production that makes large-size touch panels economically viable, thereby expanding the application range while improving productivity.
3Reliability
If separate fabrication processes are used for the lower and upper touch sensitive layers on different substrates, then production yield is improved, but the device structure becomes more complex
Solution Approach 1:
The invention segments the fabrication process into two independent processes on separate substrates, which increases production yield by eliminating cross-contamination risks. The segmented substrates are then bonded together using a bonding layer, creating a modular structure that manages complexity through systematic division rather than monolithic fabrication.
Data Source
AI summary
A capacitive touch panel sequentially has a first transparent substrate, a lower touch sensitive layer, a lower conductor layer, a lower insulation layer, a lower conductive adhesive layer, a flexible circuit board, a transparent insulation adhesive layer, an upper insulation layer, an upper conductive adhesive layer, an upper conductor layer, an upper insulation ink layer, an upper touch sensitive layer and a second transparent substrate. The aforementioned structure allows fabrication of the capacitive touch panel to be separated into a lower panel fabrication process and an upper panel fabrication process. The two independent fabrication processes prevent the capacitive touch panel from being damaged in one of the processes when the process is completed, thereby increase the yield in production and further facilitate producing large-size touch panel.