COA Substrate Segmented Conductive Layer for Ion Blocking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In COA liquid crystal displays, ion penetration through the planarization layer causes image sticking due to the weak ion-blocking capacity of the polyimide alignment film and the periodic slit angle structures of pixel electrodes, leading to resistivity and capacitance changes.
Innovation Solution
An electrically conductive layer with first and second regions is applied over the planarization layer, connected to thin-film transistors and separated at boundaries, preventing ion penetration into the liquid crystal layer by working independently in each pixel unit without short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a planarization layer is used to replace the second passivation layer to improve manufacturing capacity, then productivity is improved, but ion penetration into the liquid crystal layer occurs causing image sticking
Solution Approach 1:
The pixel electrode is divided into multiple independent conductive regions (first conductive region, second conductive region, third conductive region) that are electrically isolated from each other by insulating layers. This segmentation prevents ion penetration pathways that would otherwise connect adjacent pixels through the planarization layer, thereby maintaining ion-blocking capacity while preserving the manufacturing efficiency of using a planarization layer.
Solution Approach 2:
Insulating layers are introduced as intermediary structures between adjacent conductive regions of the pixel electrode. These insulating layers act as barriers that block ion migration paths, preventing ions from traveling through the planarization layer between pixels. This intermediary structure resolves the contradiction by maintaining the planarization layer's manufacturing advantages while adding ion-blocking functionality.
2Reliability
If a double-layer pixel electrode is added to block ion penetration, then ion-blocking capacity is improved, but device complexity and process complexity increase
Solution Approach 1:
Instead of adding a double-layer pixel electrode structure, the invention segments the single pixel electrode into multiple conductive regions separated by insulating layers. This segmentation approach achieves ion-blocking capacity without requiring additional electrode layers, thereby avoiding increased device complexity and process complexity while still preventing ion penetration effectively.
3Stability of the object's composition
If pixel electrodes are patterned to generate periodic slit angle structures for 45-degree liquid crystal alignment, then liquid crystal alignment is improved, but ion penetration pathways are created leading to image sticking
Solution Approach 1:
The pixel electrode is segmented into multiple conductive regions with insulating layers between them. This segmentation disrupts the continuous periodic slit angle structure that would otherwise create ion penetration pathways, while still maintaining the necessary 45-degree liquid crystal alignment within each individual conductive region. The insulating barriers prevent ion migration along the periodic structures.
Solution Approach 2:
Insulating layers are introduced as intermediary barriers between adjacent conductive regions. These intermediaries block the ion penetration pathways that would otherwise be created by the periodic slit angle structures, while allowing each conductive region to independently maintain the required liquid crystal alignment for optimal optical performance.
Data Source
AI summary
A color-filter on array substrate, having a first base substrate, includes a plurality of thin-film transistors (TFTs) disposed in an array on the first base substrate; color resists correspondingly disposed on one of the TFTs; a planarization layer disposed on the color resists and covering all of the color resists; and an electrically conductive layer disposed on the planarization layer. An orthogonal projection of the electrically conductive layer on the planarization layer covers the planarization layer. The electrically conductive layer comprises a plurality of first regions and second regions being separated. Each of the first regions is electrically connected to one of the TFTs. One of a plurality of protrusions is provided by the planarization layer or at least one of two adjacent color resists and corresponds to one of the second regions.