Display Sub-Electrode Slit and Passivation Thickness for Short-Circuit Prevention
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Solution Overview
Problem
Conventional display devices face issues with short-circuits and defects in the first electrode, leading to malfunctioning pixels, especially when sub-electrodes are adjacent and have varying thicknesses in the passivation layer, causing potential short-circuits and defects.
Innovation Solution
A display device design featuring a passivation layer with varying thicknesses, including a first thickness area and a second thickness area less than the first, with sub-electrodes separated by a slit, and a method for manufacturing and repairing the device by disconnecting defective sub-electrodes using a laser beam to prevent pixel malfunction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the passivation layer has uniform thickness, then the manufacturing process is simple, but short-circuits occur between adjacent sub-electrodes
Solution Approach 1:
The passivation layer is designed with different thicknesses in different regions: a first thickness in the first area and a second thickness (less than the first) in the second area adjacent to the slit. This local variation in thickness prevents short-circuits between sub-electrodes while maintaining overall structural simplicity
Solution Approach 2:
The solution addresses the short-circuit problem by introducing a thickness dimension variation in the passivation layer rather than changing the planar layout. The vertical dimension (thickness) is modified to create electrical isolation between adjacent sub-electrodes
2Area of stationary object
If sub-electrodes are placed adjacent to each other, then the pixel area is maximized, but defects in one sub-electrode cause whole pixel malfunction
Solution Approach 1:
The first electrode is divided into multiple sub-electrodes (first sub-electrode and second sub-electrode) separated by a slit. This segmentation allows the pixel to continue functioning if one sub-electrode fails, as the other sub-electrode can still operate independently
Solution Approach 2:
The passivation layer thickness is changed in the region adjacent to the slit (second area) to be less than in other regions (first area). This parameter change ensures proper electrical isolation and prevents defects from propagating between sub-electrodes
3Reliability
If the passivation layer thickness is reduced adjacent to the slit, then short-circuit risk is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The passivation layer is designed with localized thickness variation only in the critical region adjacent to the slit (second area), while maintaining uniform thickness in other areas (first area). This approach provides electrical isolation where needed without requiring precision control across the entire layer
Data Source
AI summary
A display device includes a substrate, a passivation layer on the substrate and including an area having a first thickness and an area having a second thickness less than the first thickness, a first electrode on the passivation layer and including at least two sub-electrodes spaced apart from each other by a slit having two ends, a light emitting layer on the first electrode, and a second electrode on the light emitting layer. Both ends of the slit are in one the area of the passivation layer having the second thickness.