Liquid Crystal Display Microcavity Capping Layer Alignment
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Solution Overview
Problem
Liquid crystal displays face electrical short defects between the pixel electrode and the common electrode due to mis-alignment and sagging of the common electrode during the manufacturing process, which affects the display's performance and reliability.
Innovation Solution
The design includes a microcavity with a liquid crystal injection hole, a common electrode with a projection that is bent at the end, and a capping layer that covers the injection hole, ensuring the pixel electrode is not overlapping with the common electrode projection, thereby preventing electrical shorts. This configuration also includes a groove between the microcavity and the injection hole, which is filled by the capping layer to further prevent defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the common electrode is formed during the manufacturing process, then the liquid crystal display structure is complete, but mis-alignment and sagging of the common electrode cause electrical short defects between the pixel electrode and common electrode
Solution Approach 1:
A capping layer is introduced as an intermediary element that covers the liquid crystal injection hole and prevents direct contact between the pixel electrode and common electrode projection. The capping layer acts as a mediator that eliminates the electrical short defect while allowing the common electrode projection to maintain its structural role in preventing sagging.
Solution Approach 2:
The solution adds a vertical dimension by forming a capping layer that extends over the liquid crystal injection hole. This dimensional addition creates a new protective barrier in the vertical direction, preventing horizontal electrical shorts between electrodes while maintaining the overall device structure.
2Stability of the object's composition
If the common electrode projection is designed to prevent sagging, then structural stability is improved, but the projection may cause electrical short if it overlaps with the pixel electrode
Solution Approach 1:
The capping layer serves as a mediator that allows the common electrode projection to maintain its stability function while preventing it from causing electrical shorts. The projection can extend toward the pixel electrode for structural support without creating harmful electrical contact, as the capping layer blocks the electrical pathway.
Solution Approach 2:
The common electrode is segmented into a main body and a projection portion. The projection is designed to extend only to a specific position that prevents sagging without overlapping the pixel electrode, thereby separating the structural function from the electrical function in different spatial zones.
3Ease of manufacture
If the liquid crystal injection hole is exposed, then liquid crystal filling is enabled, but the exposed hole risks contamination and electrical short defects
Solution Approach 1:
The capping layer is formed in advance to cover the liquid crystal injection hole after the liquid crystal is injected. This preliminary protective action prevents contamination and electrical shorts that would otherwise occur during subsequent manufacturing steps or device operation, while still allowing the injection hole to serve its filling function.
Solution Approach 2:
The capping layer acts as an intermediary barrier that covers the injection hole, protecting it from harmful factors such as contamination and electrical shorts. The injection hole remains functional for liquid crystal filling, but the capping layer eliminates the harmful exposure risks.
Data Source
AI summary
A liquid crystal display includes: a substrate; a thin film transistor on the substrate; a pixel electrode connected with a terminal of the thin film transistor; a microcavity on the pixel electrode, and including a plurality of regions corresponding a pixel area; a liquid crystal layer in the microcavity; a liquid crystal injection hole exposing the microcavity; a common electrode on the microcavity; a supporting member on the common electrode; and a capping layer on the supporting member and covering the liquid crystal injection hole. The pixel electrode is connected with the terminal of the thin film transistor through a contact hole, and the contact hole is within the pixel area.