MicroLED Vertical Staircase Contacts for Light Emission
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Solution Overview
Problem
The manufacturing of microLEDs (μLEDs) is hindered by the need for precise micron-level accuracy in placing and aligning these tiny devices on a substrate, along with the challenge of accommodating electrical contacts that block light emission and increase manufacturing costs.
Innovation Solution
The use of multi-tiered perimeter contacts allows for relaxed placement accuracy and wider conductor patterning, reducing the footprint of electrical contacts and enabling the formation of a staircase structure that maximizes the light-emitting surface area by separating contacts vertically, thus eliminating the need for precise rotational alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If electrical contacts are placed on the top surface of μLEDs, then electrical connections are provided, but the contacts block portions of emitted light and increase device footprint
Solution Approach 1:
The patent applies dimensionality change by transitioning electrical contacts from a 2D planar arrangement to a 3D vertical staircase structure. Multiple tiers of contacts are arranged at different heights, allowing electrical connections while minimizing the horizontal footprint and maximizing the light-emitting surface area of the μLED device.
2Ease of manufacture
If conventional single-level contacts are used, then device structure is simple, but placement accuracy must be micron-level precise and rotational alignment is required
Solution Approach 1:
By introducing vertical separation through multiple tiers, the patent relaxes lateral placement accuracy requirements. The staircase structure provides inherent alignment tolerance, eliminating the need for precise rotational alignment while maintaining electrical connection functionality.
Solution Approach 2:
The electrical contact structure is segmented into multiple discrete tiers rather than a single continuous contact layer. This segmentation allows each tier to be independently positioned and connected, reducing the cumulative precision requirements and simplifying the manufacturing process.
3Reliability
If multiple electrical contacts are placed on the same vertical level, then electrical isolation is difficult to achieve, but conductor patterning can be simplified
Solution Approach 1:
The patent uses vertical separation to achieve electrical isolation between multiple contacts. By arranging contacts on different vertical levels (tiers) separated by insulating layers, the structure provides inherent electrical isolation without requiring complex lateral patterning, thus improving reliability while managing device complexity.
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 approach reduces manufacturing complexities and costs, increases yield, and allows for the assembly of μLEDs with improved light emission efficiency by minimizing the area occupied by electrical contacts, making the production of μLED arrays more feasible.
Implementation Method 1
transfer printing microLEDs from a first substrate to a second substrate
Implementation Method 2
deep ultraviolet laser annealing to reflow solder
Implementation Method 3
deep ultraviolet laser annealing to reflow solder
Data Source
AI summary
A light emitting device that includes: a plurality of light emitting elements arranged at different locations in a common plane, each light emitting element including: at least one layer of a semiconductor material; a first electrical terminal located at a first location; a second electrical terminal located at a second location; and a third electrical terminal located at a third location; a first electrode layer including one or more electrodes; a second electrode layer including one or more electrodes; a third electrode layer including one or more electrodes; a first electrically insulating layer disposed between the plurality of light emitting elements and also disposed between the first and second electrode layers; and a second electrically insulating layer disposed between the plurality of light emitting elements and also disposed between the second and third electrode layers.