Micro LED Electrode Structure for Misalignment-Tolerant Bonding
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Solution Overview
Problem
During the manufacturing of micro light emitting display devices, micro light emitting elements often fail to be electrically connected to the pixel electrode and common electrode due to misalignment, leading to non-light-emitting issues.
Innovation Solution
A display device structure is designed with a substrate, spaced common and pixel electrodes, a bank with openings, reflective electrodes, an organic pattern layer, and connection electrodes. The connection electrodes, which include a lower and upper connection electrode, are formed in different layers to ensure electrical connection even with misaligned light-emitting elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-layer connection electrode is used to connect the light emitting element to the pixel electrode and common electrode, then the structure is simple, but misalignment causes poor bonding and electrical connection failure
Solution Approach 1:
The connection electrode is divided into two separate layers: a lower connection electrode that connects to the common electrode and an upper connection electrode that connects to the pixel electrode. This segmentation allows each layer to be independently positioned and connected, reducing the impact of misalignment and ensuring reliable electrical connection even when the light emitting element position varies slightly.
Solution Approach 2:
The solution transitions from a single-plane (2D) connection to a multi-layer (3D) connection structure. By stacking the lower and upper connection electrodes at different heights, the patent creates vertical redundancy that compensates for horizontal misalignment, effectively adding a vertical dimension to solve the alignment problem.
2Reliability
If the connection electrode area is made larger to compensate for misalignment, then connection reliability improves, but the device area increases
Solution Approach 1:
By dividing the connection function into two separate electrodes at different layers, each electrode can have a smaller individual area while collectively providing sufficient connection coverage. The lower connection electrode handles connection to the common electrode, and the upper connection electrode handles connection to the pixel electrode, distributing the area requirement across layers rather than requiring a large single-plane area.
Data Source
AI summary
The present disclosure provides a display device and a method of manufacturing the same. A display device includes a common electrode and a pixel electrode spaced from each other on a substrate, a bank having an opening exposing a portion of the pixel electrode and the common electrode, a first reflective electrode on a top surface of the bank along the opening on a top surface of the pixel electrode, and a second reflective electrode on a top surface of the bank along the opening on a top surface of the common electrode, an organic pattern layer on the pixel electrode and the common electrode in the opening, a light emitting element on the organic pattern layer and including a first contact electrode and a second contact electrode on a top surface, and a first via layer having a height that is less than that of the light emitting element.