TFT Array Panel Single Photomask Electrode Design
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Solution Overview
Problem
The manufacturing of thin film transistor (TFT) array panels with two field generating electrodes on one display panel incurs increased costs due to the need for different photomasks for forming these electrodes.
Innovation Solution
A TFT array panel design and manufacturing method where the common electrode is thicker than the pixel electrode, with a double layer structure, and both electrodes share overlapping regions, allowing for the use of a single photomask to define their openings, thereby reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If different photomasks are used to form pixel electrode and common electrode separately, then the electrodes can be formed with precise patterns, but manufacturing costs increase
Solution Approach 1:
The patent merges the formation of pixel electrode and common electrode into a single photomask process. The photomask is designed with multiple opening regions that simultaneously define both electrodes, eliminating the need for separate photomasks and reducing manufacturing steps while maintaining pattern precision
Solution Approach 2:
The photomask is designed to serve multiple functions: it defines the pixel electrode pattern, defines the common electrode pattern, and controls the thickness distribution of both electrodes through its opening design. This multi-functional approach reduces the number of manufacturing steps required
2Ease of manufacture
If a single photomask is used to form both pixel electrode and common electrode, then manufacturing costs are reduced, but the thickness of electrodes must be carefully controlled
Solution Approach 1:
The photomask is designed with different opening regions having different characteristics: first opening regions for pixel electrode formation and second opening regions for common electrode formation. These regions are positioned at different locations and have different dimensions, allowing local control of electrode thickness and pattern while using a single photomask
Solution Approach 2:
The patent controls electrode thickness not only through the vertical dimension but also by utilizing the horizontal positioning and sizing of photomask opening regions. The first and second opening regions are positioned at different locations and have different areas, enabling thickness control through spatial distribution rather than solely through layer-by-layer deposition
Data Source
AI summary
A thin film transistor array panel includes a first insulation substrate, a gate line and a data line which are positioned on the first insulation substrate, are insulated from each other, and cross each other, a thin film transistor connected to the gate line and the data line, an organic film positioned on the thin film transistor, a second passivation layer which is positioned on the organic film and defines a plurality of second openings therein, a common electrode positioned on the second passivation layer, and a pixel electrode positioned in the plurality of second openings, where a thickness of the common electrode is larger than a thickness of the pixel electrode.