Micro LED Mounting Electrode Through-Holes for Strong Laser Joining
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Solution Overview
Problem
The manufacturing of micro LED displays faces challenges in achieving strong metal joining between micro LEDs and mounting electrodes due to laser energy being attenuated by metal mounting electrodes, leading to insufficient joining at the interface.
Innovation Solution
Incorporating through holes in the mounting electrodes to allow direct laser irradiation from the substrate side, ensuring that the thermal energy reaches the interface between the micro LED and the mounting electrode, thereby enhancing the metal joining process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal mounting electrode is used to mount micro LED, then electrical connection is achieved, but laser energy is shielded and attenuated leading to insufficient joining
Solution Approach 1:
The mounting electrode is segmented by forming through-holes that divide the continuous metal structure into regions, allowing laser energy to pass through and reach the joining interface while maintaining electrical connection functionality
Solution Approach 2:
The through-hole acts as an intermediary structure that allows laser energy to penetrate through the mounting electrode to the joining interface, mediating between the laser source and the metal electrode to enable sufficient energy transmission for strong joining
2Manufacturing precision
If laser irradiation is applied to join micro LED to mounting electrode, then joining is achieved, but metal shielding prevents sufficient energy penetration to the interface
Solution Approach 1:
The mounting electrode structure is segmented with through-holes to create pathways for laser energy, allowing the laser to reach the joining interface without being completely blocked by the metal shielding
Solution Approach 2:
The mounting electrode has different properties in different regions: solid metal areas for electrical connection and through-hole areas for laser transmission, creating local quality variations that satisfy both electrical and thermal joining requirements
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method strengthens the joining between the micro LED and the array substrate, reducing point defects and improving the reliability of the display device by ensuring sufficient laser energy penetration and strong metal bonding.
Implementation Method 1
a laser is irradiated from the array substrate side to a region where the electrodes overlap
Implementation Method 2
the energy of the laser does not sufficiently reach a joining interface between the electrode of the micro LED and the mounting electrode
Data Source
AI summary
According to one embodiment, a display device includes a substrate, a drive transistor that is provided on above the substrate, a first insulating layer that is provided above the substrate, a first mounting electrode that is arranged above the first insulating layer, and a light emitting element that is mounted on the first mounting electrode and has a first electrode and a second electrode, the first electrode being electrically connected to the first mounting electrode. The first mounting electrode and the first electrode are made of a metal material and joined to each other. The first mounting electrode has at least one first through hole at a position overlapping the first electrode in plan view.