Light-Emitting Element Display Layout With Planarized Electrode Connection
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Solution Overview
Problem
Display devices face connection defects between electrodes and lower conductive layers, as well as alignment defects of light-emitting elements due to height differences formed by the electrodes.
Innovation Solution
A display device structure is proposed, featuring a first and second electrode on a substrate, with a first insulating layer made of organic material and a second insulating layer made of inorganic material. Wall patterns and a bank layer are used to position light-emitting elements between the electrodes, ensuring electrical contact through connecting electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrodes are formed with different heights to achieve electrical contact, then electrical connection is improved, but alignment defects and connection defects occur due to height differences
Solution Approach 1:
A planarization layer is introduced as an intermediary between the electrodes and the light-emitting elements. This planarization layer fills in the height differences created by the electrodes, providing a flat surface for subsequent layers. The mediator absorbs the topography variations, allowing precise alignment of light-emitting elements while maintaining reliable electrical contact through the connecting electrodes that extend into the electrode structures.
Solution Approach 2:
The problem of height differences in the horizontal plane is resolved by transitioning to the vertical dimension. The planarization layer adds a vertical dimension to compensate for height variations, creating a flat top surface. This dimensional transition allows the light-emitting elements to be aligned precisely in the horizontal plane while the vertical layer compensates for the electrode height differences.
2Reliability
If insulating layers are added to protect electrodes, then connection defects are prevented, but device complexity increases
Solution Approach 1:
The planarization layer serves multiple functions simultaneously: it provides electrical insulation between the electrodes and upper layers, fills height differences to enable precise alignment, and creates a flat surface for subsequent deposition. By combining insulation, planarization, and alignment functions in a single layer, the design avoids adding multiple separate layers, thus reducing overall device complexity while maintaining connection reliability.
Data Source
AI summary
A display device includes a first electrode and a second electrode on a substrate spaced apart from each other, a first insulating layer on the first and second electrodes, wall patterns on the first insulating layer and overlapping the first electrode and the second electrode, a second insulating layer on the first insulating layer and overlapping the wall patterns, light-emitting elements directly on the second insulating layer and between the wall patterns, a bank layer on the first insulating layer and surrounding an area including the light-emitting elements, and a first connecting electrode on the first electrode electrically contacting the light-emitting elements, and a second connecting electrode on the second electrode electrically contacting the light-emitting elements, the first insulating layer includes an organic insulating material, and the second insulating layer includes an inorganic insulating material.