Display Subpixel Anode Segmentation for Top Emission Dark Spot Normalization
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Solution Overview
Problem
In electroluminescence display apparatuses operating in top emission mode, the challenge lies in normalizing dark spots caused by particles introduced during manufacturing, as it is difficult to non-conductorize the cathode surface adjacent to these particles, leading to limitations in completely eliminating dark spots despite normalization processes.
Innovation Solution
The display apparatus incorporates a coating layer on subpixels to address the issue of particles, with a structure comprising first and second light emission areas and a non-light emission area, where the anode electrode is divided, and a cathode electrode is positioned on the light emitting element and bank, using transparent conductive materials to facilitate top emission while preventing electrical contact between cathode sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high voltage pulse is applied to the cathode to space it apart from the anode to normalize dark spots, then dark spots in bottom emission mode can be normalized, but in top emission mode with transparent conductive cathode material, the surface cannot be non-conductorized and dark spots cannot be completely eliminated
Solution Approach 1:
The anode electrode is divided into first and second divided electrodes that are spatially separated by a non-light emission area. This segmentation allows independent control of electrical connections in different regions, enabling the first divided electrode to be electrically connected to the cathode through particles while the second divided electrode remains isolated, thus normalizing display performance in top emission mode
Solution Approach 2:
Different regions of the anode electrode are given different electrical connection properties. The first divided electrode is designed to be electrically connected to the cathode (allowing current flow) while the second divided electrode is electrically isolated from the cathode (preventing current flow). This local differentiation in electrical properties enables selective normalization of dark spots based on particle location
2Manufacturing precision
If particles are introduced during manufacturing and the light emitting element is deposited on them, then the light emitting element and cathode are deposited without continuity and anode and cathode contact, but applying high voltage pulse to non-conductorize the cathode surface is ineffective for top emission mode
Solution Approach 1:
The harmful electrical connection between anode and cathode through particles is extracted by spatially separating the anode into first and second divided electrodes. The second divided electrode is positioned such that even if particles cause contact between anode and cathode, the second divided electrode remains electrically isolated from the cathode, preventing harmful current flow paths
Solution Approach 2:
A bank structure is introduced as an intermediary element in the non-light emission area between the anode and cathode. This bank provides physical separation and electrical isolation, preventing direct contact between anode and cathode in certain regions while allowing light emission areas to function normally
Data Source
AI summary
A display apparatus can include a plurality of subpixels disposed on a substrate, each of the subpixels including first and second light emission areas and a non-light emission area disposed between the first and second light emission areas. One of the plurality of subpixels can include an anode electrode disposed on the substrate and including first and second divided electrodes, a light emitting element disposed on the anode electrode in the first and second light emission areas, a bank disposed on the anode electrode in the non-light emission area, and a cathode electrode disposed on the light emitting element and the bank. The first divided electrode is disposed in the first light emission area, and the second divided electrode is disposed in the second light emission area.