Display Substrate Misalignment Prevention via Color Filter Exposure
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Solution Overview
Problem
Display substrates with plastic bases face misalignment issues due to thermal expansion and contraction during thin film transistor formation, affecting driving characteristics and display performance.
Innovation Solution
A display substrate design featuring a gate electrode, gate insulating layer, semiconductor layer, color filter layer, source and drain electrodes, protective layer, and pixel electrode, where the color filter layer exposes the semiconductor layer and reduces parasitic capacitance, and a manufacturing method involving specific layer formations and etching processes to prevent misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a plastic substrate is used to decrease thickness and weight, then the display apparatus becomes lightweight with good mobility, but the substrate repeatedly expands and shrinks due to temperature variations causing misalignment of thin film transistor layers
Solution Approach 1:
The substrate surface is divided into a first region and a second region with different material compositions. The first region has lower thermal expansion coefficient while the second region has higher thermal expansion coefficient, allowing differential expansion behavior that prevents overall substrate distortion and maintains alignment precision during manufacturing processes.
Solution Approach 2:
Different regions of the substrate are assigned different material properties specifically tailored to their functional requirements. The first region uses materials with low thermal expansion to maintain dimensional stability for critical alignment areas, while the second region uses materials with higher thermal expansion to accommodate overall substrate flexibility and weight requirements.
2Ease of manufacture
If the color filter layer covers the semiconductor layer completely, then the manufacturing process is simplified, but parasitic capacitance increases affecting driving characteristics
Solution Approach 1:
The color filter layer is strategically removed or thinned in the region corresponding to the semiconductor layer, extracting the problematic overlapping portion that causes parasitic capacitance. This creates an exposed semiconductor layer region while maintaining color filter coverage in other areas, thus reducing capacitance without completely eliminating the color filter layer.
Solution Approach 2:
The solution transitions from a complete planar coverage approach to a multi-level dimensional structure where the color filter layer exists at different heights and coverage areas. The color filter layer covers the substrate and gate electrode regions but is reduced or absent over the semiconductor layer, creating a stepped or patterned configuration that reduces parasitic capacitance while maintaining manufacturing feasibility.
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
The solution enhances driving characteristics and maintains display performance by preventing misalignment of gate and semiconductor layers, improving the reliability and efficiency of thin film transistors on flexible substrates.
Implementation Method 1
the color filter layer exposes the semiconductor layer and reduces parasitic capacitance
Data Source
AI summary
A display substrate includes a gate electrode, a gate insulating layer, and a semiconductor layer that are sequentially formed on a substrate. Also, the display substrate includes a color filter layer formed on the substrate and exposing a portion of the semiconductor layer, and source and drain electrodes that each overlap with the semiconductor layer and the color filter layer. The gate electrode, the gate insulating layer, and the semiconductor layer have the same shape as each other, and the gate electrode is insulated from the gate insulating layer and the semiconductor layer by the color filter layer.