OLED Electrode Contact Structure for Preventing Voltage Drop
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Solution Overview
Problem
In display apparatuses, such as organic light-emitting display apparatuses, voltage drops across light-emitting diodes can occur, leading to suboptimal image quality due to the configuration of transistors and electrodes.
Innovation Solution
A display apparatus design featuring a light-emitting diode with a first electrode connected to a transistor, a second electrode, and an intermediate layer, along with a conductive layer in contact with the bus line through strategically arranged insulating layers, including a third insulating layer with an overhang structure and a dummy conductive layer, to prevent voltage drops and ensure efficient electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional transistor and electrode configuration is used, then the device complexity is reduced, but voltage drops occur across light-emitting diodes leading to poor image quality
Solution Approach 1:
A conductive layer is introduced as an intermediary between the bus line and the second electrode of the light-emitting diode. This conductive layer is positioned within a cavity formed by insulating layers and makes direct contact with both the bus line and the second electrode, thereby providing a low-resistance electrical connection path that prevents voltage drops without requiring complex reconfiguration of existing transistor and electrode structures
Solution Approach 2:
The conductive layer is positioned in a third dimension within a cavity formed by multiple insulating layers (first, second, third, and fourth insulating layers). This vertical stacking approach allows the conductive layer to access both the bus line and the second electrode simultaneously, creating an efficient electrical connection without increasing planar footprint or requiring lateral routing changes
2Reliability
If multiple insulating layers with openings are added to prevent voltage drops, then voltage stability is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The insulating structure is divided into multiple discrete layers (first, second, third, and fourth insulating layers), each with specific openings (first opening, second opening, third opening, fourth opening). This segmentation allows each layer to be formed and patterned independently using standard semiconductor fabrication techniques, making the complex structure manufacturable through sequential processing steps rather than requiring a single complex formation step
Solution Approach 2:
The first and second insulating layers are formed beforehand with their respective openings before the conductive layer is deposited. This preliminary preparation of the insulating layer structure with pre-formed openings allows the conductive layer to be directly patterned and deposited in the cavity region, simplifying the overall manufacturing process by avoiding subsequent etching or opening formation steps
Data Source
AI summary
A display apparatus includes a transistor, a light-emitting diode including a first electrode electrically connected to the transistor, a second electrode, and an intermediate layer between the first and second electrodes, a bus line adjacent to the light-emitting diode, a first insulating layer on the bus line, a second insulating layer on the first insulating layer, a conductive layer electrically connected to the bus line through a first opening in the first insulating layer and a second opening in the second insulating layer, a third insulating layer on the second insulating layer and including a third opening overlapping the first opening and the second opening, and a fourth insulating layer on the third insulating layer and including a fourth opening overlapping the conductive layer, wherein a portion of the second electrode of the light-emitting diode is in contact with the conductive layer through the third opening and the fourth opening.