Touch Screen Panel Driving Shield Electrode Moisture Protection
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Solution Overview
Problem
The stability of driving/shield electrodes in touch screen panels is compromised due to exposure during the scribing process, leading to moisture infiltration and short-circuits, causing abnormal operations.
Innovation Solution
A touch screen panel design where the driving/shield electrode is formed on the opposite surface of the transparent substrate with its ends spaced apart from the substrate boundary, and a first insulation layer covers the entire exposed surface, including the sides, to prevent moisture infiltration and ensure stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If driving/shield electrodes are formed throughout the mother substrate and separated by scribing without separate patterning, then manufacturing complexity is reduced and productivity is improved, but the electrode sides are exposed during scribing causing moisture infiltration and short-circuits
Solution Approach 1:
A passivation layer is formed over the driving/shield electrodes before the scribing process to preliminarily protect the electrode sides from moisture infiltration. This preliminary protective action prevents the harmful effect of exposure during subsequent scribing operations, resolving the contradiction between manufacturing efficiency and electrode reliability.
2Area of stationary object
If the transparent substrate boundary is maximized for screen size, then display area is increased, but the driving/shield electrode becomes more vulnerable to moisture infiltration at the edges
Solution Approach 1:
The passivation layer acts as an intermediary barrier between the driving/shield electrode and the external environment. It mediates the interaction by blocking moisture infiltration paths at the electrode sides, thereby protecting the electrode while allowing the substrate boundary to be maximized for display area.
3Device complexity
If no additional insulation layer is added to cover electrode sides, then device complexity is minimized, but moisture infiltration causes short-circuits and abnormal operations
Solution Approach 1:
The passivation layer performs multiple functions simultaneously: it protects the driving/shield electrode from moisture infiltration, provides electrical insulation, and maintains a relatively simple manufacturing process. This multi-functionality addresses the reliability issue without significantly increasing device complexity.
Data Source
AI summary
A touch screen panel includes a transparent substrate; first detection cells and second detection cells alternately disposed on an active touch area of one surface of the transparent substrate in such a manner that the first detection cells are connected to each other along a first direction and second detection cells are connected to each other along a second direction; a driving/shield electrode formed throughout the other surface of the transparent substrate in such a manner that ends of the driving/shield electrode are located at an inner side of the transparent substrate while being spaced apart from a boundary line of the transparent substrate by a predetermined interval; and a first insulation layer formed throughout the other surface of the transparent substrate, on which the driving/shield electrode is formed, to cover an exposed surface of the driving/shield electrode, inclusive of sides of the driving/shield electrode.