OLED Contact Structure for Narrower Through-Hole Openings
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Solution Overview
Problem
Existing organic light-emitting elements face challenges in reducing size due to the need for deeper through-holes and wider openings to connect anode electrodes to lower-layer wiring, which hinders achieving higher definition.
Innovation Solution
The design incorporates conductors connected to both the first electrode and wiring layer, with a configuration where the conductor's area is smaller than the wiring layer, and the shortest distance from the substrate to the first electrode in the contact region is equal to or greater than the distance to the reflective layer in the emission region, allowing for reduced depth and width of the through-hole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a deep through-hole is provided to connect anode electrode to lower-layer wiring, then electrical connection is achieved, but the opening width must be increased which prevents size reduction
Solution Approach 1:
The invention transitions from a single deep through-hole structure to a multi-layered contact structure involving both through-holes and side-wall contacts. The anode electrode makes contact with lower-layer wiring not only at the bottom of through-holes but also along the side walls of the interlayer insulating layer, effectively utilizing vertical and lateral dimensions simultaneously to achieve reliable electrical connection with reduced opening width.
Solution Approach 2:
The electrical connection path is segmented into multiple contact regions: some through-holes provide direct bottom contacts, while other regions provide side-wall contacts along the interlayer insulating layer. This segmentation allows the total contact area to be distributed, maintaining electrical reliability while reducing the opening width of individual through-holes.
2Reliability
If the through-hole is made deeper for direct contact, then electrical connection is improved, but manufacturing complexity increases
Solution Approach 1:
Different regions of the contact structure have different qualities: some through-holes are made deeper to provide direct bottom contacts, while other regions utilize side-wall contacts that do not require such extreme depths. This local differentiation allows the overall structure to achieve reliable electrical connection without uniformly increasing through-hole depth across all contact points, thereby reducing manufacturing complexity.
3Reliability
If opening width is increased to accommodate deep through-holes, then electrical connection is achieved, but element size cannot be reduced
Solution Approach 1:
The invention utilizes the vertical dimension by implementing side-wall contacts along the interlayer insulating layer, in addition to bottom contacts through through-holes. This multi-dimensional approach allows electrical connection to be achieved without increasing the horizontal opening width, thereby enabling element size reduction while maintaining connection reliability.
Solution Approach 2:
The contact structure is segmented into multiple contact points and regions distributed across different locations. By distributing the electrical connection function across multiple segmented contact regions (bottom contacts and side-wall contacts), the opening width of each individual contact can be reduced, enabling overall element size reduction while maintaining total connection reliability.
Data Source
AI summary
The present disclosure provides a light-emitting element having an emission region and a contact region. In the emission region the light-emitting element has, a wiring layer, an interlayer insulating layer, a reflective layer, an optical adjustment layer, a first electrode, a light-emitting layer, and a second electrode, in this order from a substrate side; and in the contact region has, the wiring layer, a conductor, the first electrode, the light-emitting layer, and the second electrode, in this order from the substrate side. The conductor is electrically connected to both the first electrode and the wiring layer. A shortest distance between the first electrode and the substrate in the contact region is equal to or greater than a shortest distance between the reflective layer and the substrate in the emission region.